FreeBSD/Linux Kernel Cross Reference
sys/conf/NOTES

     # $FreeBSD: releng/5.1/sys/conf/NOTES 115010 2003-05-15 02:10:30Z jmallett $
     #
     # NOTES -- Lines that can be cut/pasted into kernel and hints configs.
     #
     # Lines that begin with 'device', 'options', 'machine', 'ident', 'maxusers',
     # 'makeoptions', 'hints', etc. go into the kernel configuration that you
     # run config(8) with.
     #
     # Lines that begin with 'hint.' are NOT for config(8), they go into your
    # hints file.  See /boot/device.hints and/or the 'hints' config(8) directive.
    #
    # Please use ``make LINT'' to create an old-style LINT file if you want to
    # do kernel test-builds.
    #
    # This file contains machine independent kernel configuration notes.  For
    # machine dependent notes, look in /sys/<arch>/conf/NOTES.
    #
    
    #
    # NOTES conventions and style guide:
    #
    # Large block comments should begin and end with a line containing only a
    # comment character.
    #
    # To describe a particular object, a block comment (if it exists) should
    # come first.  Next should come device, options, and hints lines in that
    # order.  All device and option lines must be described by a comment that
    # doesn't just expand the device or option name.  Use only a concise
    # comment on the same line if possible.  Very detailed descriptions of
    # devices and subsystems belong in manpages.
    #
    # A space followed by a tab separates 'option' from an option name.  Two
    # spaces followed by a tab separate 'device' from a device name.  Comments
    # after an option or device should use one space after the comment character.
    # To comment out a negative option that disables code and thus should not be
    # enabled for LINT builds, precede 'option' with "#!".
    #
    
    #
    # This is the ``identification'' of the kernel.  Usually this should
    # be the same as the name of your kernel.
    #
    ident           LINT
    
    #
    # The `maxusers' parameter controls the static sizing of a number of
    # internal system tables by a formula defined in subr_param.c.
    # Omitting this parameter or setting it to 0 will cause the system to
    # auto-size based on physical memory.
    #
    maxusers        10
    
    #
    # The `makeoptions' parameter allows variables to be passed to the
    # generated Makefile in the build area.
    #
    # CONF_CFLAGS gives some extra compiler flags that are added to ${CFLAGS}
    # after most other flags.  Here we use it to inhibit use of non-optimal
    # gcc builtin functions (e.g., memcmp).
    #
    # DEBUG happens to be magic.
    # The following is equivalent to 'config -g KERNELNAME' and creates
    # 'kernel.debug' compiled with -g debugging as well as a normal
    # 'kernel'.  Use 'make install.debug' to install the debug kernel
    # but that isn't normally necessary as the debug symbols are not loaded
    # by the kernel and are not useful there anyway.
    #
    # KERNEL can be overridden so that you can change the default name of your
    # kernel.
    #
    # MODULES_OVERRIDE can be used to limit modules built to a specific list.
    #
    makeoptions     CONF_CFLAGS=-fno-builtin  #Don't allow use of memcmp, etc.
    #makeoptions    DEBUG=-g                #Build kernel with gdb(1) debug symbols
    #makeoptions    KERNEL=foo              #Build kernel "foo" and install "/foo"
    # Only build Linux API modules and plus those parts of the sound system I need.
    #makeoptions    MODULES_OVERRIDE="linux sound/snd sound/pcm sound/driver/maestro3"
    makeoptions     DESTDIR=/tmp
    
    
    #
    # Certain applications can grow to be larger than the 512M limit
    # that FreeBSD initially imposes.  Below are some options to
    # allow that limit to grow to 1GB, and can be increased further
    # with changing the parameters.  MAXDSIZ is the maximum that the
    # limit can be set to, and the DFLDSIZ is the default value for
    # the limit.  MAXSSIZ is the maximum that the stack limit can be
    # set to.  You might want to set the default lower than the max, 
    # and explicitly set the maximum with a shell command for processes
    # that regularly exceed the limit like INND.
    #
    options         MAXDSIZ=(1024UL*1024*1024)
    options         MAXSSIZ=(128UL*1024*1024)
    options         DFLDSIZ=(1024UL*1024*1024)
    
    #
    # BLKDEV_IOSIZE sets the default block size used in user block
    # device I/O.  Note that this value will be overriden by the label
    # when specifying a block device from a label with a non-0
   # partition blocksize.  The default is PAGE_SIZE.
   #
   options         BLKDEV_IOSIZE=8192
   
   # Options for the VM subsystem
   options         PQ_CACHESIZE=512        # color for 512k/16k cache
   # Deprecated options supported for backwards compatibility
   #options        PQ_NOOPT                # No coloring
   #options        PQ_LARGECACHE           # color for 512k/16k cache
   #options        PQ_HUGECACHE            # color for 1024k/16k cache
   #options        PQ_MEDIUMCACHE          # color for 256k/16k cache
   #options        PQ_NORMALCACHE          # color for 64k/16k cache
   
   # This allows you to actually store this configuration file into
   # the kernel binary itself, where it may be later read by saying:
   #    strings -n 3 /boot/kernel/kernel | sed -n 's/^___//p' > MYKERNEL
   #
   options         INCLUDE_CONFIG_FILE     # Include this file in kernel
   
   options         GEOM_AES                # Don't use, use GEOM_BDE
   options         GEOM_APPLE              # Apple partitioning
   options         GEOM_BDE                # Disk encryption.
   options         GEOM_BSD                # BSD disklabels
   options         GEOM_GPT                # GPT partitioning
   options         GEOM_MBR                # DOS/MBR partitioning
   options         GEOM_PC98               # NEC PC9800 partitioning
   options         GEOM_SUNLABEL           # Sun/Solaris partitioning
   options         GEOM_VOL                # Volume names from UFS superblock
   
   #
   # The root device and filesystem type can be compiled in;
   # this provides a fallback option if the root device cannot
   # be correctly guessed by the bootstrap code, or an override if
   # the RB_DFLTROOT flag (-r) is specified when booting the kernel.
   #
   options         ROOTDEVNAME=\"ufs:da0s2e\"
   
   
   #####################################################################
   # Scheduler options:
   #
   # Specifying one of SCHED_4BSD or SCHED_ULE is mandatory.  These options
   # select which scheduler is compiled in.
   #
   # SCHED_4BSD is the historical, proven, BSD scheduler.  It has a global run
   # queue and no cpu affinity which makes it suboptimal for SMP.  It has very
   # good interactivity and priority selection.
   #
   # SCHED_ULE is a new experimental scheduler that has been designed for SMP,
   # but will work just fine on UP too.  Users of this scheduler should expect
   # some hicups and be prepaired to provide feedback.
   #
   options         SCHED_4BSD
   #options        SCHED_ULE
   
   #####################################################################
   # SMP OPTIONS:
   #
   # SMP enables building of a Symmetric MultiProcessor Kernel.
   
   # Mandatory:
   options         SMP                     # Symmetric MultiProcessor Kernel
   
   # ADAPTIVE_MUTEXES changes the behavior of blocking mutexes to spin
   # if the thread that currently owns the mutex is executing on another
   # CPU.
   options         ADAPTIVE_MUTEXES
   
   # SMP Debugging Options:
   #
   # MUTEX_DEBUG enables various extra assertions in the mutex code.
   # WITNESS enables the witness code which detects deadlocks and cycles
   #         during locking operations.
   # WITNESS_DDB causes the witness code to drop into the kernel debugger if
   #         a lock heirarchy violation occurs or if locks are held when going to
   #         sleep.
   # WITNESS_SKIPSPIN disables the witness checks on spin mutexes.
   options         MUTEX_DEBUG
   options         WITNESS
   options         WITNESS_DDB
   options         WITNESS_SKIPSPIN
   
   #
   # MUTEX_PROFILING - Profiling mutual exclusion locks (mutexes).  This
   # records four numbers for each acquisition point (identified by
   # source file name and line number): longest time held, total time held,
   # number of non-recursive acquisitions, and average time held. Measurements
   # are made and stored in nanoseconds (using nanotime(9)), but are presented
   # in microseconds, which should be sufficient for the locks which actually
   # want this (those that are held long and / or often).  The MUTEX_PROFILING
   # option has the following sysctl namespace for controlling and viewing its
   # operation:
   #
   #  debug.mutex.prof.enable - enable / disable profiling
   #  debug.mutex.prof.acquisitions - number of mutex acquisitions held
   #  debug.mutex.prof.records - number of acquisition points recorded
   #  debug.mutex.prof.maxrecords - max number of acquisition points
   #  debug.mutex.prof.rejected - number of rejections (due to full table)
   #  debug.mutex.prof.hashsize - hash size
   #  debug.mutex.prof.collisions - number of hash collisions
   #  debug.mutex.prof.stats - profiling statistics
   #
   options         MUTEX_PROFILING
   
   
   #####################################################################
   # COMPATIBILITY OPTIONS                                             
   
   #
   # Implement system calls compatible with 4.3BSD and older versions of
   # FreeBSD.  You probably do NOT want to remove this as much current code
   # still relies on the 4.3 emulation.  Note that some architectures that
   # are supported by FreeBSD do not include support for certain important
   # aspects of this compatibility option, namely those related to the
   # signal delivery mechanism.
   #
   options         COMPAT_43
   
   #
   # Be compatible with SunOS.  The COMPAT_43 option above pulls in most
   # (all?) of the changes that this option turns on.
   #
   options         COMPAT_SUNOS
   
   # Enable FreeBSD4 compatibility syscalls
   options         COMPAT_FREEBSD4
   
   #
   # These three options provide support for System V Interface
   # Definition-style interprocess communication, in the form of shared
   # memory, semaphores, and message queues, respectively.
   #
   options         SYSVSHM
   options         SYSVSEM
   options         SYSVMSG
   
   
   #####################################################################
   # DEBUGGING OPTIONS
   
   #
   # Enable the kernel debugger.
   #
   options         DDB
   
   #
   # Use direct symbol lookup routines for ddb instead of the kernel linker
   # ones, so that symbols (mostly) work before the kernel linker has been
   # initialized.  This is not the default because it breaks ddb's lookup of
   # symbols in loaded modules.
   #
   #!options       DDB_NOKLDSYM
   
   #
   # Print a stack trace of the current thread out on the console for a panic.
   #
   options         DDB_TRACE
   
   #
   # Don't drop into DDB for a panic. Intended for unattended operation
   # where you may want to drop to DDB from the console, but still want
   # the machine to recover from a panic
   #
   options         DDB_UNATTENDED
   
   #
   # If using GDB remote mode to debug the kernel, there's a non-standard
   # extension to the remote protocol that can be used to use the serial
   # port as both the debugging port and the system console.  It's non-
   # standard and you're on your own if you enable it.  See also the
   # "remotechat" variables in the FreeBSD specific version of gdb.
   #
   options         GDB_REMOTE_CHAT
   
   #
   # KTRACE enables the system-call tracing facility ktrace(2).  To be more
   # SMP-friendly, KTRACE uses a worker thread to process most trace events
   # asynchronously to the thread generating the event.  This requires a
   # pre-allocated store of objects representing trace events.  The
   # KTRACE_REQUEST_POOL option specifies the initial size of this store.
   # The size of the pool can be adjusted both at boottime and runtime via
   # the kern.ktrace_request_pool tunable and sysctl.
   #
   options         KTRACE                  #kernel tracing
   options         KTRACE_REQUEST_POOL=101
   
   #
   # KTR is a kernel tracing mechanism imported from BSD/OS.  Currently it
   # has no userland interface aside from a few sysctl's.  It is enabled with
   # the KTR option.  KTR_ENTRIES defines the number of entries in the circular
   # trace buffer.  KTR_COMPILE defines the mask of events to compile into the
   # kernel as defined by the KTR_* constants in <sys/ktr.h>.  KTR_MASK defines the
   # initial value of the ktr_mask variable which determines at runtime what
   # events to trace.  KTR_CPUMASK determines which CPU's log events, with
   # bit X corresponding to cpu X.  KTR_VERBOSE enables dumping of KTR events
   # to the console by default.  This functionality can be toggled via the
   # debug.ktr_verbose sysctl and defaults to off if KTR_VERBOSE is not defined.
   #
   options         KTR
   options         KTR_ENTRIES=1024
   options         KTR_COMPILE=(KTR_INTR|KTR_PROC)
   options         KTR_MASK=KTR_INTR
   options         KTR_CPUMASK=0x3
   options         KTR_VERBOSE
   
   #
   # The INVARIANTS option is used in a number of source files to enable
   # extra sanity checking of internal structures.  This support is not
   # enabled by default because of the extra time it would take to check
   # for these conditions, which can only occur as a result of
   # programming errors.
   #
   options         INVARIANTS
   
   #
   # The INVARIANT_SUPPORT option makes us compile in support for
   # verifying some of the internal structures.  It is a prerequisite for
   # 'INVARIANTS', as enabling 'INVARIANTS' will make these functions be
   # called.  The intent is that you can set 'INVARIANTS' for single
   # source files (by changing the source file or specifying it on the
   # command line) if you have 'INVARIANT_SUPPORT' enabled.  Also, if you
   # wish to build a kernel module with 'INVARIANTS', then adding
   # 'INVARIANT_SUPPORT' to your kernel will provide all the necessary
   # infrastructure without the added overhead.
   #
   options         INVARIANT_SUPPORT
   
   #
   # The DIAGNOSTIC option is used to enable extra debugging information
   # from some parts of the kernel.  As this makes everything more noisy,
   # it is disabled by default.
   #
   options         DIAGNOSTIC
   
   #
   # REGRESSION causes optional kernel interfaces necessary only for regression
   # testing to be enabled.  These interfaces may consitute security risks
   # when enabled, as they permit processes to easily modify aspects of the
   # run-time environment to reproduce unlikely or unusual (possibly normally
   # impossible) scenarios.
   #
   options         REGRESSION
   
   #
   # RESTARTABLE_PANICS allows one to continue from a panic as if it were
   # a call to the debugger via the Debugger() function instead.  It is only
   # useful if a kernel debugger is present.  To restart from a panic, reset
   # the panicstr variable to NULL and continue execution.  This option is
   # for development use only and should NOT be used in production systems
   # to "workaround" a panic.
   #
   #options        RESTARTABLE_PANICS
   
   #
   # This option let some drivers co-exist that can't co-exist in a running
   # system.  This is used to be able to compile all kernel code in one go for
   # quality assurance purposes (like this file, which the option takes it name
   # from.)
   #
   options         COMPILING_LINT
   
   
   #####################################################################
   # NETWORKING OPTIONS
   
   #
   # Protocol families:
   #  Only the INET (Internet) family is officially supported in FreeBSD.
   #
   options         INET                    #Internet communications protocols
   options         INET6                   #IPv6 communications protocols
   options         IPSEC                   #IP security
   options         IPSEC_ESP               #IP security (crypto; define w/ IPSEC)
   options         IPSEC_DEBUG             #debug for IP security
   #
   # Set IPSEC_FILTERGIF to force packets coming through a gif tunnel
   # to be processed by any configured packet filtering (ipfw, ipf).
   # The default is that packets coming from a tunnel are _not_ processed;
   # they are assumed trusted.
   #
   # Note that enabling this can be problematic as there are no mechanisms
   # in place for distinguishing packets coming out of a tunnel (e.g. no
   # encX devices as found on openbsd).
   #
   #options        IPSEC_FILTERGIF         #filter ipsec packets from a tunnel
   
   #options        FAST_IPSEC              #new IPsec (cannot define w/ IPSEC)
   
   options         IPX                     #IPX/SPX communications protocols
   options         IPXIP                   #IPX in IP encapsulation (not available)
   
   #options        NCP                     #NetWare Core protocol
   
   options         NETATALK                #Appletalk communications protocols
   options         NETATALKDEBUG           #Appletalk debugging
   
   #
   # SMB/CIFS requester
   # NETSMB enables support for SMB protocol, it requires LIBMCHAIN and LIBICONV
   # options.
   # NETSMBCRYPTO enables support for encrypted passwords.
   options         NETSMB                  #SMB/CIFS requester
   options         NETSMBCRYPTO            #encrypted password support for SMB
   
   # mchain library. It can be either loaded as KLD or compiled into kernel
   options         LIBMCHAIN
   
   # netgraph(4). Enable the base netgraph code with the NETGRAPH option.
   # Individual node types can be enabled with the corresponding option
   # listed below; however, this is not strictly necessary as netgraph
   # will automatically load the corresponding KLD module if the node type
   # is not already compiled into the kernel. Each type below has a
   # corresponding man page, e.g., ng_async(8).
   options         NETGRAPH                #netgraph(4) system
   options         NETGRAPH_ASYNC
   options         NETGRAPH_BPF
   options         NETGRAPH_BRIDGE
   options         NETGRAPH_CISCO
   options         NETGRAPH_ECHO
   options         NETGRAPH_ETHER
   options         NETGRAPH_FRAME_RELAY
   options         NETGRAPH_GIF
   options         NETGRAPH_GIF_DEMUX
   options         NETGRAPH_HOLE
   options         NETGRAPH_IFACE
   options         NETGRAPH_IP_INPUT
   options         NETGRAPH_KSOCKET
   options         NETGRAPH_L2TP
   options         NETGRAPH_LMI
   # MPPC compression requires proprietary files (not included)
   #options        NETGRAPH_MPPC_COMPRESSION
   options         NETGRAPH_MPPC_ENCRYPTION
   options         NETGRAPH_ONE2MANY
   options         NETGRAPH_PPP
   options         NETGRAPH_PPPOE
   options         NETGRAPH_PPTPGRE
   options         NETGRAPH_RFC1490
   options         NETGRAPH_SOCKET
   options         NETGRAPH_SPLIT
   options         NETGRAPH_TEE
   options         NETGRAPH_TTY
   options         NETGRAPH_UI
   options         NETGRAPH_VJC
   
   device          mn      # Munich32x/Falc54 Nx64kbit/sec cards.
   device          lmc     # tulip based LanMedia WAN cards
   device          musycc  # LMC/SBE LMC1504 quad T1/E1
   
   #
   # Network interfaces:
   #  The `loop' device is MANDATORY when networking is enabled.
   #  The `ether' device provides generic code to handle
   #  Ethernets; it is MANDATORY when an Ethernet device driver is
   #  configured or token-ring is enabled.
   #  The 'wlan' device provides generic code to support 802.11
   #  drivers, including host AP mode; it is MANDATORY for the wi
   #  driver and will eventually be required by all 802.11 drivers.
   #  The `fddi' device provides generic code to support FDDI.
   #  The `arcnet' device provides generic code to support Arcnet.
   #  The `sppp' device serves a similar role for certain types
   #  of synchronous PPP links (like `cx', `ar').
   #  The `sl' device implements the Serial Line IP (SLIP) service.
   #  The `ppp' device implements the Point-to-Point Protocol.
   #  The `bpf' device enables the Berkeley Packet Filter.  Be
   #  aware of the legal and administrative consequences of enabling this
   #  option.  The number of devices determines the maximum number of
   #  simultaneous BPF clients programs runnable.
   #  The `disc' device implements a minimal network interface,
   #  which throws away all packets sent and never receives any.  It is
   #  included for testing purposes.  This shows up as the `ds' interface.
   #  The `tap' device is a pty-like virtual Ethernet interface
   #  The `tun' device implements (user-)ppp and nos-tun
   #  The `gif' device implements IPv6 over IP4 tunneling,
   #  IPv4 over IPv6 tunneling, IPv4 over IPv4 tunneling and
   #  IPv6 over IPv6 tunneling.
   #  The `gre' device implements two types of IP4 over IP4 tunneling:
   #  GRE and MOBILE, as specified in the RFC1701 and RFC2004.
   #  The XBONEHACK option allows the same pair of addresses to be configured on
   #  multiple gif interfaces.
   #  The `faith' device captures packets sent to it and diverts them
   #  to the IPv4/IPv6 translation daemon.
   #  The `stf' device implements 6to4 encapsulation.
   #  The `ef' device provides support for multiple ethernet frame types
   #  specified via ETHER_* options. See ef(4) for details.
   #
   # The PPP_BSDCOMP option enables support for compress(1) style entire
   # packet compression, the PPP_DEFLATE is for zlib/gzip style compression.
   # PPP_FILTER enables code for filtering the ppp data stream and selecting
   # events for resetting the demand dial activity timer - requires bpf.
   # See pppd(8) for more details.
   #
   device          ether                   #Generic Ethernet
   device          vlan                    #VLAN support
   device          wlan                    #802.11 support
   device          token                   #Generic TokenRing
   device          fddi                    #Generic FDDI
   device          arcnet                  #Generic Arcnet
   device          sppp                    #Generic Synchronous PPP
   device          loop                    #Network loopback device
   device          bpf                     #Berkeley packet filter
   device          disc                    #Discard device (ds0, ds1, etc)
   device          tap                     #Virtual Ethernet driver
   device          tun                     #Tunnel driver (ppp(8), nos-tun(8))
   device          sl                      #Serial Line IP
   device          gre                     #IP over IP tunneling
   device          ppp                     #Point-to-point protocol
   options         PPP_BSDCOMP             #PPP BSD-compress support
   options         PPP_DEFLATE             #PPP zlib/deflate/gzip support
   options         PPP_FILTER              #enable bpf filtering (needs bpf)
   
   device          ef                      # Multiple ethernet frames support
   options         ETHER_II                # enable Ethernet_II frame
   options         ETHER_8023              # enable Ethernet_802.3 (Novell) frame
   options         ETHER_8022              # enable Ethernet_802.2 frame
   options         ETHER_SNAP              # enable Ethernet_802.2/SNAP frame
   
   # for IPv6
   device          gif                     #IPv6 and IPv4 tunneling
   options         XBONEHACK
   device          faith                   #for IPv6 and IPv4 translation
   device          stf                     #6to4 IPv6 over IPv4 encapsulation
   
   #
   # Internet family options:
   #
   # MROUTING enables the kernel multicast packet forwarder, which works
   # with mrouted(8).
   #
   # IPFIREWALL enables support for IP firewall construction, in
   # conjunction with the `ipfw' program.  IPFIREWALL_VERBOSE sends
   # logged packets to the system logger.  IPFIREWALL_VERBOSE_LIMIT
   # limits the number of times a matching entry can be logged.
   #
   # WARNING:  IPFIREWALL defaults to a policy of "deny ip from any to any"
   # and if you do not add other rules during startup to allow access,
   # YOU WILL LOCK YOURSELF OUT.  It is suggested that you set firewall_type=open
   # in /etc/rc.conf when first enabling this feature, then refining the
   # firewall rules in /etc/rc.firewall after you've tested that the new kernel
   # feature works properly.
   #
   # IPFIREWALL_DEFAULT_TO_ACCEPT causes the default rule (at boot) to
   # allow everything.  Use with care, if a cracker can crash your
   # firewall machine, they can get to your protected machines.  However,
   # if you are using it as an as-needed filter for specific problems as
   # they arise, then this may be for you.  Changing the default to 'allow'
   # means that you won't get stuck if the kernel and /sbin/ipfw binary get
   # out of sync.
   #
   # IPDIVERT enables the divert IP sockets, used by ``ipfw divert''
   #
   # IPSTEALTH enables code to support stealth forwarding (i.e., forwarding
   # packets without touching the ttl).  This can be useful to hide firewalls
   # from traceroute and similar tools.
   #
   # PFIL_HOOKS enables an abtraction layer which is meant to be used in
   # network code where filtering is required.  See the pfil(9) man page.
   # This option is a subset of the IPFILTER option.
   #
   # TCPDEBUG enables code which keeps traces of the TCP state machine
   # for sockets with the SO_DEBUG option set, which can then be examined
   # using the trpt(8) utility.
   #
   options         MROUTING                # Multicast routing
   options         IPFIREWALL              #firewall
   options         IPFIREWALL_VERBOSE      #enable logging to syslogd(8)
   options         IPFIREWALL_FORWARD      #enable transparent proxy support
   options         IPFIREWALL_VERBOSE_LIMIT=100    #limit verbosity
   options         IPFIREWALL_DEFAULT_TO_ACCEPT    #allow everything by default
   options         IPV6FIREWALL            #firewall for IPv6
   options         IPV6FIREWALL_VERBOSE
   options         IPV6FIREWALL_VERBOSE_LIMIT=100
   options         IPV6FIREWALL_DEFAULT_TO_ACCEPT
   options         IPDIVERT                #divert sockets
   options         IPFILTER                #ipfilter support
   options         IPFILTER_LOG            #ipfilter logging
   options         IPFILTER_DEFAULT_BLOCK  #block all packets by default
   options         IPSTEALTH               #support for stealth forwarding
   options         PFIL_HOOKS
   options         TCPDEBUG
   
   # The MBUF_STRESS_TEST option enables options which create
   # various random failures / extreme cases related to mbuf
   # functions.  See the mbuf(9) manpage for a list of available
   # test cases.
   options         MBUF_STRESS_TEST
   
   # RANDOM_IP_ID causes the ID field in IP packets to be randomized
   # instead of incremented by 1 with each packet generated.  This
   # option closes a minor information leak which allows remote
   # observers to determine the rate of packet generation on the
   # machine by watching the counter.
   options         RANDOM_IP_ID
   
   # Statically Link in accept filters
   options         ACCEPT_FILTER_DATA
   options         ACCEPT_FILTER_HTTP
   
   # TCP_DROP_SYNFIN adds support for ignoring TCP packets with SYN+FIN. This
   # prevents nmap et al. from identifying the TCP/IP stack, but breaks support
   # for RFC1644 extensions and is not recommended for web servers.
   #
   options         TCP_DROP_SYNFIN         #drop TCP packets with SYN+FIN
   
   # DUMMYNET enables the "dummynet" bandwidth limiter. You need
   # IPFIREWALL as well. See the dummynet(4) and ipfw(8) manpages for more info.
   # When you run DUMMYNET it is advisable to also have "options HZ=1000"
   # to achieve a smoother scheduling of the traffic.
   #
   # BRIDGE enables bridging between ethernet cards -- see bridge(4).
   # You can use IPFIREWALL and DUMMYNET together with bridging.
   #
   options         DUMMYNET
   options         BRIDGE
   
   # Zero copy sockets support.  This enables "zero copy" for sending and
   # receving data via a socket.  The send side works for any type of NIC,
   # the receive side only works for NICs that support MTUs greater than the
   # page size of your architecture and that support header splitting.  See
   # zero_copy(9) for more details.
   options         ZERO_COPY_SOCKETS
   
   #
   # ATM (HARP version) options
   #
   # ATM_CORE includes the base ATM functionality code.  This must be included
   #       for ATM support.
   #
   # ATM_IP includes support for running IP over ATM.
   #
   # At least one (and usually only one) of the following signalling managers
   # must be included (note that all signalling managers include PVC support):
   # ATM_SIGPVC includes support for the PVC-only signalling manager `sigpvc'.
   # ATM_SPANS includes support for the `spans' signalling manager, which runs
   #       the FORE Systems's proprietary SPANS signalling protocol.
   # ATM_UNI includes support for the `uni30' and `uni31' signalling managers,
   #       which run the ATM Forum UNI 3.x signalling protocols.
   #
   # The `hea' driver provides support for the Efficient Networks, Inc.
   # ENI-155p ATM PCI Adapter.
   #
   # The `hfa' driver provides support for the FORE Systems, Inc.
   # PCA-200E ATM PCI Adapter.
   #
   options         ATM_CORE                #core ATM protocol family
   options         ATM_IP                  #IP over ATM support
   options         ATM_SIGPVC              #SIGPVC signalling manager
   options         ATM_SPANS               #SPANS signalling manager
   options         ATM_UNI                 #UNI signalling manager
   
   device          hea                     #Efficient ENI-155p ATM PCI
   device          hfa                     #FORE PCA-200E ATM PCI
   
   
   #####################################################################
   # FILESYSTEM OPTIONS
   
   #
   # Only the root, /usr, and /tmp filesystems need be statically
   # compiled; everything else will be automatically loaded at mount
   # time.  (Exception: the UFS family--- FFS --- cannot
   # currently be demand-loaded.)  Some people still prefer to statically
   # compile other filesystems as well.
   #
   # NB: The NULL, PORTAL, UMAP and UNION filesystems are known to be
   # buggy, and WILL panic your system if you attempt to do anything with
   # them.  They are included here as an incentive for some enterprising
   # soul to sit down and fix them.
   #
   
   # One of these is mandatory:
   options         FFS                     #Fast filesystem
   options         NFSCLIENT               #Network File System
   options         NFSSERVER               #Network File System
   
   # The rest are optional:
   options         CD9660                  #ISO 9660 filesystem
   options         FDESCFS                 #File descriptor filesystem
   options         HPFS                    #OS/2 File system
   options         MSDOSFS                 #MS DOS File System (FAT, FAT32)
   options         NTFS                    #NT File System
   options         NULLFS                  #NULL filesystem
   #options        NWFS                    #NetWare filesystem
   options         PORTALFS                #Portal filesystem
   options         PROCFS                  #Process filesystem (requires PSEUDOFS)
   options         PSEUDOFS                #Pseudo-filesystem framework
   options         SMBFS                   #SMB/CIFS filesystem
   options         UDF                     #Universal Disk Format
   options         UMAPFS                  #UID map filesystem
   options         UNIONFS                 #Union filesystem
   # The xFS_ROOT options REQUIRE the associated ``options xFS''
   options         NFS_ROOT                #NFS usable as root device
   
   # Soft updates is a technique for improving filesystem speed and
   # making abrupt shutdown less risky.
   #
   options         SOFTUPDATES
   
   # Extended attributes allow additional data to be associated with files,
   # and is used for ACLs, Capabilities, and MAC labels.
   # See src/sys/ufs/ufs/README.extattr for more information.
   options         UFS_EXTATTR
   options         UFS_EXTATTR_AUTOSTART
   
   # Access Control List support for UFS filesystems.  The current ACL
   # implementation requires extended attribute support, UFS_EXTATTR,
   # for the underlying filesystem.
   # See src/sys/ufs/ufs/README.acls for more information.
   options         UFS_ACL
   
   # Directory hashing improves the speed of operations on very large
   # directories at the expense of some memory.
   options         UFS_DIRHASH
   
   # Make space in the kernel for a root filesystem on a md device.
   # Define to the number of kilobytes to reserve for the filesystem.
   options         MD_ROOT_SIZE=10
   
   # Make the md device a potential root device, either with preloaded
   # images of type mfs_root or md_root.
   options         MD_ROOT
   
   # Allow this many swap-devices.
   #
   # In order to manage swap, the system must reserve bitmap space that
   # scales with the largest mounted swap device multiplied by NSWAPDEV, 
   # irregardless of whether other swap devices exist or not.  So it
   # is not a good idea to make this value too large.
   options         NSWAPDEV=5
   
   # Disk quotas are supported when this option is enabled.
   options         QUOTA                   #enable disk quotas
   
   # If you are running a machine just as a fileserver for PC and MAC
   # users, using SAMBA or Netatalk, you may consider setting this option
   # and keeping all those users' directories on a filesystem that is
   # mounted with the suiddir option. This gives new files the same
   # ownership as the directory (similar to group). It's a security hole
   # if you let these users run programs, so confine it to file-servers
   # (but it'll save you lots of headaches in those cases). Root owned
   # directories are exempt and X bits are cleared. The suid bit must be
   # set on the directory as well; see chmod(1) PC owners can't see/set
   # ownerships so they keep getting their toes trodden on. This saves
   # you all the support calls as the filesystem it's used on will act as
   # they expect: "It's my dir so it must be my file".
   #
   options         SUIDDIR
   
   # NFS options:
   options         NFS_MINATTRTIMO=3       # VREG attrib cache timeout in sec
   options         NFS_MAXATTRTIMO=60
   options         NFS_MINDIRATTRTIMO=30   # VDIR attrib cache timeout in sec
   options         NFS_MAXDIRATTRTIMO=60
   options         NFS_GATHERDELAY=10      # Default write gather delay (msec)
   options         NFS_WDELAYHASHSIZ=16    # and with this
   options         NFS_DEBUG               # Enable NFS Debugging
   
   # Coda stuff:
   options         CODA                    #CODA filesystem.
   device          vcoda   4               #coda minicache <-> venus comm.
   
   #
   # Add support for the EXT2FS filesystem of Linux fame.  Be a bit
   # careful with this - the ext2fs code has a tendency to lag behind
   # changes and not be exercised very much, so mounting read/write could
   # be dangerous (and even mounting read only could result in panics.)
   #
   options         EXT2FS
   
   # Use real implementations of the aio_* system calls.  There are numerous
   # stability and security issues in the current aio code that make it
   # unsuitable for inclusion on machines with untrusted local users.
   options         VFS_AIO
   
   # Cryptographically secure random number generator; /dev/[u]random
   device          random
   
   
   #####################################################################
   # POSIX P1003.1B
   
   # Real time extensions added in the 1993 Posix
   # _KPOSIX_PRIORITY_SCHEDULING: Build in _POSIX_PRIORITY_SCHEDULING
   
   options         _KPOSIX_PRIORITY_SCHEDULING
   # p1003_1b_semaphores are very experimental,
   # user should be ready to assist in debugging if problems arise.
   options         P1003_1B_SEMAPHORES
   
   
   #####################################################################
   # SECURITY POLICY PARAMETERS
   
   # Support for Mandatory Access Control (MAC):
   options         MAC
   options         MAC_BIBA
   options         MAC_BSDEXTENDED
   options         MAC_DEBUG
   options         MAC_IFOFF
   options         MAC_LOMAC
   options         MAC_MLS
   options         MAC_NONE
   options         MAC_PARTITION
   options         MAC_PORTACL
   options         MAC_SEEOTHERUIDS
   options         MAC_TEST
   
   
   #####################################################################
   # CLOCK OPTIONS
   
   # The granularity of operation is controlled by the kernel option HZ whose
   # default value (100) means a granularity of 10ms (1s/HZ).
   # Some subsystems, such as DUMMYNET, might benefit from a smaller
   # granularity such as 1ms or less, for a smoother scheduling of packets.
   # Consider, however, that reducing the granularity too much might
   # cause excessive overhead in clock interrupt processing,
   # potentially causing ticks to be missed and thus actually reducing
   # the accuracy of operation.
   
   options         HZ=100
   
   # If you see the "calcru: negative time of %ld usec for pid %d (%s)\n"
   # message you probably have some broken sw/hw which disables interrupts
   # for too long.  You can make the system more resistant to this by
   # choosing a high value for NTIMECOUNTER.  The default is 5, there
   # is no upper limit but more than a couple of hundred are not productive.
   
   options         NTIMECOUNTER=20
   
   # Enable support for the kernel PLL to use an external PPS signal,
   # under supervision of [x]ntpd(8)
   # More info in ntpd documentation: http://www.eecis.udel.edu/~ntp
   
   options         PPS_SYNC
   
   
   #####################################################################
   # SCSI DEVICES
   
   # SCSI DEVICE CONFIGURATION
   
   # The SCSI subsystem consists of the `base' SCSI code, a number of
   # high-level SCSI device `type' drivers, and the low-level host-adapter
   # device drivers.  The host adapters are listed in the ISA and PCI
   # device configuration sections below.
   #
   # Beginning with FreeBSD 2.0.5 you can wire down your SCSI devices so
   # that a given bus, target, and LUN always come on line as the same
   # device unit.  In earlier versions the unit numbers were assigned
   # in the order that the devices were probed on the SCSI bus.  This
   # means that if you removed a disk drive, you may have had to rewrite
   # your /etc/fstab file, and also that you had to be careful when adding
   # a new disk as it may have been probed earlier and moved your device
   # configuration around.
   
   # This old behavior is maintained as the default behavior.  The unit
   # assignment begins with the first non-wired down unit for a device
   # type.  For example, if you wire a disk as "da3" then the first
   # non-wired disk will be assigned da4.
   
   # The syntax for wiring down devices is:
   
   hint.scbus.0.at="ahc0"
   hint.scbus.1.at="ahc1"
   hint.scbus.1.bus="0"
   hint.scbus.3.at="ahc2"
   hint.scbus.3.bus="0"
   hint.scbus.2.at="ahc2"
   hint.scbus.2.bus="1"
   hint.da.0.at="scbus0"
   hint.da.0.target="0"
   hint.da.0.unit="0"
   hint.da.1.at="scbus3"
   hint.da.1.target="1"
   hint.da.2.at="scbus2"
   hint.da.2.target="3"
   hint.sa.1.at="scbus1"
   hint.sa.1.target="6"
   
   # "units" (SCSI logical unit number) that are not specified are
   # treated as if specified as LUN 0.
   
   # All SCSI devices allocate as many units as are required.
   
   # The ch driver drives SCSI Media Changer ("jukebox") devices.
   #
   # The da driver drives SCSI Direct Access ("disk") and Optical Media
   # ("WORM") devices.
   #
   # The sa driver drives SCSI Sequential Access ("tape") devices.
   #
   # The cd driver drives SCSI Read Only Direct Access ("cd") devices.
   #
   # The ses driver drives SCSI Envinronment Services ("ses") and
   # SAF-TE ("SCSI Accessable Fault-Tolerant Enclosure") devices.
   #
   # The pt driver drives SCSI Processor devices.
   #
   # 
   # Target Mode support is provided here but also requires that a SIM
   # (SCSI Host Adapter Driver) provide support as well.
   #
   # The targ driver provides target mode support as a Processor type device.
   # It exists to give the minimal context necessary to respond to Inquiry
   # commands. There is a sample user application that shows how the rest
   # of the command support might be done in /usr/share/examples/scsi_target.
   #
   # The targbh driver provides target mode support and exists to respond
   # to incoming commands that do not otherwise have a logical unit assigned
   # to them.
   # 
   # The "unknown" device (uk? in pre-2.0.5) is now part of the base SCSI
   # configuration as the "pass" driver.
   
   device          scbus           #base SCSI code
   device          ch              #SCSI media changers
   device          da              #SCSI direct access devices (aka disks)
   device          sa              #SCSI tapes
   device          cd              #SCSI CD-ROMs
   device          ses             #SCSI Environmental Services (and SAF-TE)
   device          pt              #SCSI processor 
   device          targ            #SCSI Target Mode Code
   device          targbh          #SCSI Target Mode Blackhole Device
   device          pass            #CAM passthrough driver
   
   # CAM OPTIONS:
   # debugging options:
   # -- NOTE --  If you specify one of the bus/target/lun options, you must
   #             specify them all!
   # CAMDEBUG: When defined enables debugging macros
   # CAM_DEBUG_BUS:  Debug the given bus.  Use -1 to debug all busses.
   # CAM_DEBUG_TARGET:  Debug the given target.  Use -1 to debug all targets.
   # CAM_DEBUG_LUN:  Debug the given lun.  Use -1 to debug all luns.
   # CAM_DEBUG_FLAGS:  OR together CAM_DEBUG_INFO, CAM_DEBUG_TRACE,
   #                   CAM_DEBUG_SUBTRACE, and CAM_DEBUG_CDB
   #
   # CAM_MAX_HIGHPOWER: Maximum number of concurrent high power (start unit) cmds
   # CAM_NEW_TRAN_CODE: this is the new transport layer code that will be switched
   #                       to soon
   # SCSI_NO_SENSE_STRINGS: When defined disables sense descriptions
   # SCSI_NO_OP_STRINGS: When defined disables opcode descriptions
   # SCSI_DELAY: The number of MILLISECONDS to freeze the SIM (scsi adapter)
   #             queue after a bus reset, and the number of milliseconds to
   #             freeze the device queue after a bus device reset.  This
   #             can be changed at boot and runtime with the
   #             kern.cam.scsi_delay tunable/sysctl.
   options         CAMDEBUG
   options         CAM_DEBUG_BUS=-1
   options         CAM_DEBUG_TARGET=-1
   options         CAM_DEBUG_LUN=-1
   options         CAM_DEBUG_FLAGS=(CAM_DEBUG_INFO|CAM_DEBUG_TRACE|CAM_DEBUG_CDB)
   options         CAM_MAX_HIGHPOWER=4
   options         SCSI_NO_SENSE_STRINGS
   options         SCSI_NO_OP_STRINGS
   options         SCSI_DELAY=8000 # Be pessimistic about Joe SCSI device
   
   # Options for the CAM CDROM driver:
   # CHANGER_MIN_BUSY_SECONDS: Guaranteed minimum time quantum for a changer LUN
   # CHANGER_MAX_BUSY_SECONDS: Maximum time quantum per changer LUN, only
   #                           enforced if there is I/O waiting for another LUN
   # The compiled in defaults for these variables are 2 and 10 seconds,
   # respectively.
   #
   # These can also be changed on the fly with the following sysctl variables:
   # kern.cam.cd.changer.min_busy_seconds
   # kern.cam.cd.changer.max_busy_seconds
   #
   options         CHANGER_MIN_BUSY_SECONDS=2
   options         CHANGER_MAX_BUSY_SECONDS=10
   
   # Options for the CAM sequential access driver:
   # SA_IO_TIMEOUT: Timeout for read/write/wfm  operations, in minutes
   # SA_SPACE_TIMEOUT: Timeout for space operations, in minutes
   # SA_REWIND_TIMEOUT: Timeout for rewind operations, in minutes
   # SA_ERASE_TIMEOUT: Timeout for erase operations, in minutes
   # SA_1FM_AT_EOD: Default to model which only has a default one filemark at EOT.
   options         SA_IO_TIMEOUT=4
   options         SA_SPACE_TIMEOUT=60
   options         SA_REWIND_TIMEOUT=(2*60)
   options         SA_ERASE_TIMEOUT=(4*60)
   options         SA_1FM_AT_EOD
   
   # Optional timeout for the CAM processor target (pt) device
   # This is specified in seconds.  The default is 60 seconds.
   options         SCSI_PT_DEFAULT_TIMEOUT=60
   
   # Optional enable of doing SES passthrough on other devices (e.g., disks)
   #
   # Normally disabled because a lot of newer SCSI disks report themselves
   # as having SES capabilities, but this can then clot up attempts to build
   # build a topology with the SES device that's on the box these drives
   # are in....
   options         SES_ENABLE_PASSTHROUGH
   
   
   #####################################################################
   # MISCELLANEOUS DEVICES AND OPTIONS
   
   # The `pty' device usually turns out to be ``effectively mandatory'',
   # as it is required for `telnetd', `rlogind', `screen', `emacs', and
  # `xterm', among others.
  
  device          pty             #Pseudo ttys
  device          nmdm            #back-to-back tty devices
  device          md              #Memory/malloc disk
  device          snp             #Snoop device - to look at pty/vty/etc..
  device          ccd             #Concatenated disk driver
  
  # Configuring Vinum into the kernel is not necessary, since the kld
  # module gets started automatically when vinum(8) starts.  This
  # device is also untested.  Use at your own risk.
  #
  # The option VINUMDEBUG must match the value set in CFLAGS
  # in src/sbin/vinum/Makefile.  Failure to do so will result in
  # the following message from vinum(8):
  #
  # Can't get vinum config: Invalid argument
  #
  # see vinum(4) for more reasons not to use these options.
  device          vinum           #Vinum concat/mirror/raid driver
  options         VINUMDEBUG      #enable Vinum debugging hooks
  
  # RAIDframe device.  RAID_AUTOCONFIG allows RAIDframe to search all of the
  # disk devices in the system looking for components that it recognizes (already
  # configured once before) and auto-configured them into arrays.
  device          raidframe
  options         RAID_AUTOCONFIG
  
  # Kernel side iconv library
  options         LIBICONV
  
  # Size of the kernel message buffer.  Should be N * pagesize.
  options         MSGBUF_SIZE=40960
  
  # Maximum size of a tty or pty input buffer.
  options         TTYHOG=8193
  
  
  #####################################################################
  # HARDWARE DEVICE CONFIGURATION
  
  # For ISA the required hints are listed.
  # EISA, MCA, PCI and pccard are self identifying buses, so no hints
  # are needed.
  
  #
  # Mandatory devices:
  #
  
  # The keyboard controller; it controls the keyboard and the PS/2 mouse.
  device          atkbdc
  hint.atkbdc.0.at="isa"
  hint.atkbdc.0.port="0x060"
  
  # The AT keyboard
  device          atkbd
  hint.atkbd.0.at="atkbdc"
  hint.atkbd.0.irq="1"
  
  # Options for atkbd:
  options         ATKBD_DFLT_KEYMAP       # specify the built-in keymap
  makeoptions     ATKBD_DFLT_KEYMAP=jp.106
  
  # These options are valid for other keyboard drivers as well.
  options         KBD_DISABLE_KEYMAP_LOAD # refuse to load a keymap
  options         KBD_INSTALL_CDEV        # install a CDEV entry in /dev
  
  # `flags' for atkbd:
  #       0x01    Force detection of keyboard, else we always assume a keyboard
  #       0x02    Don't reset keyboard, useful for some newer ThinkPads
  #       0x03    Force detection and avoid reset, might help with certain
  #               dockingstations
  #       0x04    Old-style (XT) keyboard support, useful for older ThinkPads
  
  # PS/2 mouse
  device          psm
  hint.psm.0.at="atkbdc"
  hint.psm.0.irq="12"
  
  # Options for psm:
  options         PSM_HOOKRESUME          #hook the system resume event, useful
                                          #for some laptops
  options         PSM_RESETAFTERSUSPEND   #reset the device at the resume event
  
  # Video card driver for VGA adapters.
  device          vga
  hint.vga.0.at="isa"
  
  # Options for vga:
  # Try the following option if the mouse pointer is not drawn correctly
  # or font does not seem to be loaded properly.  May cause flicker on
  # some systems.
  options         VGA_ALT_SEQACCESS
  
  # If you can dispense with some vga driver features, you may want to
  # use the following options to save some memory.
  #options        VGA_NO_FONT_LOADING     # don't save/load font
  #options        VGA_NO_MODE_CHANGE      # don't change video modes
  
  # Older video cards may require this option for proper operation.
  options         VGA_SLOW_IOACCESS       # do byte-wide i/o's to TS and GDC regs
  
  # The following option probably won't work with the LCD displays.
  options         VGA_WIDTH90             # support 90 column modes
  
  options         FB_DEBUG                # Frame buffer debugging
  
  device          splash                  # Splash screen and screen saver support
  
  # Various screen savers.
  device          blank_saver
  device          daemon_saver
  device          fade_saver
  device          fire_saver
  device          green_saver
  device          logo_saver
  device          rain_saver
  device          star_saver
  device          warp_saver
  
  # The syscons console driver (sco color console compatible).
  device          sc
  hint.sc.0.at="isa"
  options         MAXCONS=16              # number of virtual consoles
  options         SC_ALT_MOUSE_IMAGE      # simplified mouse cursor in text mode
  options         SC_DFLT_FONT            # compile font in
  makeoptions     SC_DFLT_FONT=cp850
  options         SC_DISABLE_DDBKEY       # disable `debug' key
  options         SC_DISABLE_REBOOT       # disable reboot key sequence
  options         SC_HISTORY_SIZE=200     # number of history buffer lines
  options         SC_MOUSE_CHAR=0x3       # char code for text mode mouse cursor
  options         SC_PIXEL_MODE           # add support for the raster text mode
  
  # The following options will let you change the default colors of syscons.
  options         SC_NORM_ATTR=(FG_GREEN|BG_BLACK)
  options         SC_NORM_REV_ATTR=(FG_YELLOW|BG_GREEN)
  options         SC_KERNEL_CONS_ATTR=(FG_RED|BG_BLACK)
  options         SC_KERNEL_CONS_REV_ATTR=(FG_BLACK|BG_RED)
  
  # The following options will let you change the default behaviour of
  # cut-n-paste feature
  options         SC_CUT_SPACES2TABS      # convert leading spaces into tabs
  options         SC_CUT_SEPCHARS=\"x09\" # set of characters that delimit words
                                          # (default is single space - \"x20\")
  
  # If you have a two button mouse, you may want to add the following option
  # to use the right button of the mouse to paste text.
  options         SC_TWOBUTTON_MOUSE
  
  # You can selectively disable features in syscons.
  options         SC_NO_CUTPASTE
  options         SC_NO_FONT_LOADING
  options         SC_NO_HISTORY
  options         SC_NO_SYSMOUSE
  options         SC_NO_SUSPEND_VTYSWITCH
  
  # `flags' for sc
  #       0x80    Put the video card in the VESA 800x600 dots, 16 color mode
  #       0x100   Probe for a keyboard device periodically if one is not present
  
  #
  # Optional devices:
  #
  
  #
  # SCSI host adapters:
  #
  # adv: All Narrow SCSI bus AdvanSys controllers.
  # adw: Second Generation AdvanSys controllers including the ADV940UW.
  # aha: Adaptec 154x/1535/1640
  # ahb: Adaptec 174x EISA controllers
  # ahc: Adaptec 274x/284x/2910/293x/294x/394x/3950x/3960x/398X/4944/
  #      19160x/29160x, aic7770/aic78xx
  # ahd: Adaptec 29320/39320 Controllers.
  # aic: Adaptec 6260/6360, APA-1460 (PC Card), NEC PC9801-100 (C-BUS)
  # amd: Support for the AMD 53C974 SCSI host adapter chip as found on devices
  #      such as the Tekram DC-390(T).
  # bt:  Most Buslogic controllers: including BT-445, BT-54x, BT-64x, BT-74x,
  #      BT-75x, BT-946, BT-948, BT-956, BT-958, SDC3211B, SDC3211F, SDC3222F
  # isp: Qlogic ISP 1020, 1040 and 1040B PCI SCSI host adapters,
  #      ISP 1240 Dual Ultra SCSI, ISP 1080 and 1280 (Dual) Ultra2,
  #      ISP 12160 Ultra3 SCSI,
  #      Qlogic ISP 2100 and ISP 2200 1Gb Fibre Channel host adapters.
  #      Qlogic ISP 2300 and ISP 2312 2Gb Fibre Channel host adapters.
  # ispfw: Firmware module for Qlogic host adapters
  # mpt: LSI-Logic MPT/Fusion 53c1020 or 53c1030 Ultra4
  #      or FC9x9 Fibre Channel host adapters.
  # ncr: NCR 53C810, 53C825 self-contained SCSI host adapters.
  # sym: Symbios/Logic 53C8XX family of PCI-SCSI I/O processors:
  #      53C810, 53C810A, 53C815, 53C825,  53C825A, 53C860, 53C875, 
  #      53C876, 53C885,  53C895, 53C895A, 53C896,  53C897, 53C1510D, 
  #      53C1010-33, 53C1010-66.
  # trm: Tekram DC395U/UW/F DC315U adapters.
  # wds: WD7000
  
  #
  # Note that the order is important in order for Buslogic ISA/EISA cards to be
  # probed correctly.
  #
  device          bt
  hint.bt.0.at="isa"
  hint.bt.0.port="0x330"
  device          adv
  hint.adv.0.at="isa"
  device          adw
  device          aha
  hint.aha.0.at="isa"
  device          aic
  hint.aic.0.at="isa"
  device          ahb
  device          ahc
  device          ahd
  device          amd
  device          isp
  hint.isp.0.disable="1"
  hint.isp.0.role="3"
  hint.isp.0.prefer_iomap="1"
  hint.isp.0.prefer_memmap="1"
  hint.isp.0.fwload_disable="1"
  hint.isp.0.ignore_nvram="1"
  hint.isp.0.fullduplex="1"
  hint.isp.0.topology="lport"
  hint.isp.0.topology="nport"
  hint.isp.0.topology="lport-only"
  hint.isp.0.topology="nport-only"
  # we can't get u_int64_t types, nor can we get strings if it's got
  # a leading 0x, hence this silly dodge.
  hint.isp.0.portwnn="w50000000aaaa0000"
  hint.isp.0.nodewnn="w50000000aaaa0001"
  device          ispfw
  device          mpt
  device          ncr
  device          sym
  device          trm
  device          wds
  hint.wds.0.at="isa"
  hint.wds.0.port="0x350"
  hint.wds.0.irq="11"
  hint.wds.0.drq="6"
  
  # The aic7xxx driver will attempt to use memory mapped I/O for all PCI
  # controllers that have it configured only if this option is set. Unfortunately,
  # this doesn't work on some motherboards, which prevents it from being the
  # default.
  options         AHC_ALLOW_MEMIO
  
  # Dump the contents of the ahc controller configuration PROM.
  options         AHC_DUMP_EEPROM
  
  # Bitmap of units to enable targetmode operations.
  options         AHC_TMODE_ENABLE
  
  # Compile in aic79xx debugging code.
  options         AHD_DEBUG
  
  # Aic79xx driver debugging options.   
  # See the ahd(4) manpage
  options         AHD_DEBUG_OPTS=0xFFFFFFFF
  
  # Print human-readable register definitions when debugging
  options         AHD_REG_PRETTY_PRINT
  
  # The adw driver will attempt to use memory mapped I/O for all PCI
  # controllers that have it configured only if this option is set.
  options         ADW_ALLOW_MEMIO
  
  # Options used in dev/isp/ (Qlogic SCSI/FC driver).
  #
  #       ISP_TARGET_MODE         -       enable target mode operation
  #
  options         ISP_TARGET_MODE=1
  
  # Options used in dev/sym/ (Symbios SCSI driver).
  #options        SYM_SETUP_LP_PROBE_MAP  #-Low Priority Probe Map (bits)
                                          # Allows the ncr to take precedence
                                          # 1 (1<<0) -> 810a, 860
                                          # 2 (1<<1) -> 825a, 875, 885, 895
                                          # 4 (1<<2) -> 895a, 896, 1510d 
  #options        SYM_SETUP_SCSI_DIFF     #-HVD support for 825a, 875, 885
                                          # disabled:0 (default), enabled:1
  #options        SYM_SETUP_PCI_PARITY    #-PCI parity checking
                                          # disabled:0, enabled:1 (default)
  #options        SYM_SETUP_MAX_LUN       #-Number of LUNs supported
                                          # default:8, range:[1..64]
  
  # The 'asr' driver provides support for current DPT/Adaptec SCSI RAID
  # controllers (SmartRAID V and VI and later).
  # These controllers require the CAM infrastructure.
  #
  device          asr
  
  # The 'dpt' driver provides support for old DPT controllers (http://www.dpt.com/).
  # These have hardware RAID-{0,1,5} support, and do multi-initiator I/O.
  # The DPT controllers are commonly re-licensed under other brand-names -
  # some controllers by Olivetti, Dec, HP, AT&T, SNI, AST, Alphatronic, NEC and
  # Compaq are actually DPT controllers.
  #
  # See src/sys/dev/dpt for debugging and other subtle options.
  #   DPT_MEASURE_PERFORMANCE Enables a set of (semi)invasive metrics. Various
  #                           instruments are enabled.  The tools in
  #                           /usr/sbin/dpt_* assume these to be enabled.
  #   DPT_HANDLE_TIMEOUTS     Normally device timeouts are handled by the DPT.
  #                           If you ant the driver to handle timeouts, enable
  #                           this option.  If your system is very busy, this
  #                           option will create more trouble than solve.
  #   DPT_TIMEOUT_FACTOR      Used to compute the excessive amount of time to
  #                           wait when timing out with the above option.
  #  DPT_DEBUG_xxxx           These are controllable from sys/dev/dpt/dpt.h
  #  DPT_LOST_IRQ             When enabled, will try, once per second, to catch
  #                           any interrupt that got lost.  Seems to help in some
  #                           DPT-firmware/Motherboard combinations.  Minimal
  #                           cost, great benefit.
  #  DPT_RESET_HBA            Make "reset" actually reset the controller
  #                           instead of fudging it.  Only enable this if you
  #                           are 100% certain you need it.
  
  device          dpt
  
  # DPT options
  #!CAM# options  DPT_MEASURE_PERFORMANCE
  #!CAM# options  DPT_HANDLE_TIMEOUTS
  options         DPT_TIMEOUT_FACTOR=4
  options         DPT_LOST_IRQ
  options         DPT_RESET_HBA
  options         DPT_ALLOW_MEMIO
  
  #
  # Compaq "CISS" RAID controllers (SmartRAID 5* series)
  # These controllers have a SCSI-like interface, and require the
  # CAM infrastructure.
  #
  device          ciss
  
  #
  # Intel Integrated RAID controllers.
  # This driver was developed and is maintained by Intel.  Contacts
  # at Intel for this driver are
  # "Kannanthanam, Boji T" <boji.t.kannanthanam@intel.com> and
  # "Leubner, Achim" <achim.leubner@intel.com>.
  #
  device          iir
  
  #
  # Mylex AcceleRAID and eXtremeRAID controllers with v6 and later
  # firmware.  These controllers have a SCSI-like interface, and require
  # the CAM infrastructure.
  #
  device          mly
  
  #
  # Compaq Smart RAID, Mylex DAC960 and AMI MegaRAID controllers.  Only
  # one entry is needed; the code will find and configure all supported
  # controllers.
  #
  device          ida             # Compaq Smart RAID
  device          mlx             # Mylex DAC960
  device          amr             # AMI MegaRAID
  
  #
  # 3ware ATA RAID
  #
  device          twe             # 3ware ATA RAID
  
  #
  # The 'ATA' driver supports all ATA and ATAPI devices, including PC Card
  # devices. You only need one "device ata" for it to find all
  # PCI and PC Card ATA/ATAPI devices on modern machines.
  device          ata
  device          atadisk         # ATA disk drives
  device          atapicd         # ATAPI CDROM drives
  device          atapifd         # ATAPI floppy drives
  device          atapist         # ATAPI tape drives
  device          atapicam        # emulate ATAPI devices as SCSI ditto via CAM
                                  # needs CAM to be present (scbus & pass)
  #
  # For older non-PCI, non-PnPBIOS systems, these are the hints lines to add:
  hint.ata.0.at="isa"
  hint.ata.0.port="0x1f0"
  hint.ata.0.irq="14"
  hint.ata.1.at="isa"
  hint.ata.1.port="0x170"
  hint.ata.1.irq="15"
  
  #
  # The following options are valid on the ATA driver:
  #
  # ATA_STATIC_ID:        controller numbering is static ie depends on location
  #                       else the device numbers are dynamically allocated.
  
  options         ATA_STATIC_ID
  
  #
  # Standard floppy disk controllers and floppy tapes, supports
  # the Y-E DATA External FDD (PC Card)
  #
  device          fdc
  hint.fdc.0.at="isa"
  hint.fdc.0.port="0x3F0"
  hint.fdc.0.irq="6"
  hint.fdc.0.drq="2"
  #
  # FDC_DEBUG enables floppy debugging.  Since the debug output is huge, you
  # gotta turn it actually on by setting the variable fd_debug with DDB,
  # however.
  options         FDC_DEBUG
  #
  # Activate this line if you happen to have an Insight floppy tape.
  # Probing them proved to be dangerous for people with floppy disks only,
  # so it's "hidden" behind a flag:
  #hint.fdc.0.flags="1"
  
  # Specify floppy devices
  hint.fd.0.at="fdc0"
  hint.fd.0.drive="0"
  hint.fd.1.at="fdc0"
  hint.fd.1.drive="1"
  
  #
  # sio: serial ports (see sio(4)), including support for various
  #      PC Card devices, such as Modem and NICs (see etc/defaults/pccard.conf)
  
  device          sio
  hint.sio.0.at="isa"
  hint.sio.0.port="0x3F8"
  hint.sio.0.flags="0x10"
  hint.sio.0.irq="4"
  
  #
  # `flags' for serial drivers that support consoles (only for sio now):
  #       0x10    enable console support for this unit.  The other console flags
  #               are ignored unless this is set.  Enabling console support does
  #               not make the unit the preferred console - boot with -h or set
  #               the 0x20 flag for that.  Currently, at most one unit can have
  #               console support; the first one (in config file order) with
  #               this flag set is preferred.  Setting this flag for sio0 gives
  #               the old behaviour.
  #       0x20    force this unit to be the console (unless there is another
  #               higher priority console).  This replaces the COMCONSOLE option.
  #       0x40    reserve this unit for low level console operations.  Do not
  #               access the device in any normal way.
  #       0x80    use this port for serial line gdb support in ddb.
  #
  # PnP `flags'
  #       0x1     disable probing of this device.  Used to prevent your modem
  #               from being attached as a PnP modem.
  #
  
  # Options for serial drivers that support consoles (only for sio now):
  options         BREAK_TO_DEBUGGER       #a BREAK on a comconsole goes to
                                          #DDB, if available.
  options         CONSPEED=115200         # speed for serial console
                                          # (default 9600)
  
  # Solaris implements a new BREAK which is initiated by a character
  # sequence CR ~ ^b which is similar to a familiar pattern used on
  # Sun servers by the Remote Console.
  options         ALT_BREAK_TO_DEBUGGER
  
  # Options for sio:
  options         COM_ESP                 #code for Hayes ESP
  options         COM_MULTIPORT           #code for some cards with shared IRQs
  
  # Other flags for sio that aren't documented in the man page.
  #       0x20000 enable hardware RTS/CTS and larger FIFOs.  Only works for
  #               ST16650A-compatible UARTs.
  
  # PCI Universal Communications driver
  # Supports various single and multi port PCI serial cards. Maybe later
  # also the parallel ports on combination serial/parallel cards. New cards
  # can be added in src/sys/dev/puc/pucdata.c.
  #
  # If the PUC_FASTINTR option is used the driver will try to use fast
  # interrupts. The card must then be the only user of that interrupt.
  # Interrupts cannot be shared when using PUC_FASTINTR.
  device          puc
  options         PUC_FASTINTR
  
  #
  # Network interfaces:
  #
  # MII bus support is required for some PCI 10/100 ethernet NICs,
  # namely those which use MII-compliant transceivers or implement
  # tranceiver control interfaces that operate like an MII. Adding
  # "device miibus0" to the kernel config pulls in support for
  # the generic miibus API and all of the PHY drivers, including a
  # generic one for PHYs that aren't specifically handled by an
  # individual driver.
  device          miibus
  
  # an:   Aironet 4500/4800 802.11 wireless adapters. Supports the PCMCIA,
  #       PCI and ISA varieties.
  # awi:  Support for IEEE 802.11 PC Card devices using the AMD Am79C930 and
  #       Harris (Intersil) Chipset with PCnetMobile firmware by AMD.
  # bge:  Support for gigabit ethernet adapters based on the Broadcom
  #       BCM570x family of controllers, including the 3Com 3c996-T,
  #       the Netgear GA302T, the SysKonnect SK-9D21 and SK-9D41, and
  #       the embedded gigE NICs on Dell PowerEdge 2550 servers.
  # cm:   Arcnet SMC COM90c26 / SMC COM90c56
  #       (and SMC COM90c66 in '56 compatibility mode) adapters.
  # cnw:  Xircom CNW/Netware Airsurfer PC Card adapter
  # cs:   IBM Etherjet and other Crystal Semi CS89x0-based adapters
  # dc:   Support for PCI fast ethernet adapters based on the DEC/Intel 21143
  #       and various workalikes including:
  #       the ADMtek AL981 Comet and AN985 Centaur, the ASIX Electronics
  #       AX88140A and AX88141, the Davicom DM9100 and DM9102, the Lite-On
  #       82c168 and 82c169 PNIC, the Lite-On/Macronix LC82C115 PNIC II
  #       and the Macronix 98713/98713A/98715/98715A/98725 PMAC. This driver
  #       replaces the old al, ax, dm, pn and mx drivers.  List of brands:
  #       Digital DE500-BA, Kingston KNE100TX, D-Link DFE-570TX, SOHOware SFA110, 
  #       SVEC PN102-TX, CNet Pro110B, 120A, and 120B, Compex RL100-TX, 
  #       LinkSys LNE100TX, LNE100TX V2.0, Jaton XpressNet, Alfa Inc GFC2204,
  #       KNE110TX.
  # de:   Digital Equipment DC21040
  # em:   Intel Pro/1000 Gigabit Ethernet 82542, 82543, 82544 based adapters.
  # ep:   3Com 3C509, 3C529, 3C556, 3C562D, 3C563D, 3C572, 3C574X, 3C579, 3C589
  #       and PC Card devices using these chipsets.
  # ex:   Intel EtherExpress Pro/10 and other i82595-based adapters,
  #       Olicom Ethernet PC Card devices.
  # fe:   Fujitsu MB86960A/MB86965A Ethernet
  # fea:  DEC DEFEA EISA FDDI adapter
  # fpa:  Support for the Digital DEFPA PCI FDDI. `device fddi' is also needed.
  # fxp:  Intel EtherExpress Pro/100B
  #       (hint of prefer_iomap can be done to prefer I/O instead of Mem mapping)
  # gx:   Intel Pro/1000 Gigabit Ethernet (82542, 82543-F, 82543-T)
  # lge:  Support for PCI gigabit ethernet adapters based on the Level 1
  #       LXT1001 NetCellerator chipset. This includes the D-Link DGE-500SX,
  #       SMC TigerCard 1000 (SMC9462SX), and some Addtron cards.
  # my:   Myson Fast Ethernet (MTD80X, MTD89X)
  # nge:  Support for PCI gigabit ethernet adapters based on the National
  #       Semiconductor DP83820 and DP83821 chipset. This includes the
  #       SMC EZ Card 1000 (SMC9462TX), D-Link DGE-500T, Asante FriendlyNet
  #       GigaNIX 1000TA and 1000TPC, the Addtron AEG320T, the LinkSys
  #       EG1032 and EG1064, the Surecom EP-320G-TX and the Netgear GA622T.
  # pcn:  Support for PCI fast ethernet adapters based on the AMD Am79c97x
  #       chipsets, including the PCnet/FAST, PCnet/FAST+, PCnet/PRO and
  #       PCnet/Home. These were previously handled by the lnc driver (and
  #       still will be if you leave this driver out of the kernel).
  # rl:   Support for PCI fast ethernet adapters based on the RealTek 8129/8139
  #       chipset.  Note that the RealTek driver defaults to using programmed
  #       I/O to do register accesses because memory mapped mode seems to cause
  #       severe lockups on SMP hardware.  This driver also supports the
  #       Accton EN1207D `Cheetah' adapter, which uses a chip called
  #       the MPX 5030/5038, which is either a RealTek in disguise or a
  #       RealTek workalike.  Note that the D-Link DFE-530TX+ uses the RealTek
  #       chipset and is supported by this driver, not the 'vr' driver.
  # sf:   Support for Adaptec Duralink PCI fast ethernet adapters based on the
  #       Adaptec AIC-6915 "starfire" controller.
  #       This includes dual and quad port cards, as well as one 100baseFX card.
  #       Most of these are 64-bit PCI devices, except for one single port
  #       card which is 32-bit.
  # sis:  Support for NICs based on the Silicon Integrated Systems SiS 900,
  #       SiS 7016 and NS DP83815 PCI fast ethernet controller chips.
  # sbsh: Support for Granch SBNI16 SHDSL modem PCI adapters
  # sk:   Support for the SysKonnect SK-984x series PCI gigabit ethernet NICs.
  #       This includes the SK-9841 and SK-9842 single port cards (single mode
  #       and multimode fiber) and the SK-9843 and SK-9844 dual port cards
  #       (also single mode and multimode).
  #       The driver will autodetect the number of ports on the card and
  #       attach each one as a separate network interface.
  # sn:   Support for ISA and PC Card Ethernet devices using the
  #       SMC91C90/92/94/95 chips.
  # ste:  Sundance Technologies ST201 PCI fast ethernet controller, includes
  #       the D-Link DFE-550TX.
  # ti:   Support for PCI gigabit ethernet NICs based on the Alteon Networks
  #       Tigon 1 and Tigon 2 chipsets.  This includes the Alteon AceNIC, the
  #       3Com 3c985, the Netgear GA620 and various others.  Note that you will
  #       probably want to bump up NMBCLUSTERS a lot to use this driver.
  # tl:   Support for the Texas Instruments TNETE100 series 'ThunderLAN'
  #       cards and integrated ethernet controllers.  This includes several
  #       Compaq Netelligent 10/100 cards and the built-in ethernet controllers
  #       in several Compaq Prosignia, Proliant and Deskpro systems.  It also
  #       supports several Olicom 10Mbps and 10/100 boards.
  # tx:   SMC 9432 TX, BTX and FTX cards. (SMC EtherPower II serie)
  # txp:  Support for 3Com 3cR990 cards with the "Typhoon" chipset
  # vr:   Support for various fast ethernet adapters based on the VIA
  #       Technologies VT3043 `Rhine I' and VT86C100A `Rhine II' chips,
  #       including the D-Link DFE530TX (see 'rl' for DFE530TX+), the Hawking 
  #       Technologies PN102TX, and the AOpen/Acer ALN-320.
  # vx:   3Com 3C590 and 3C595
  # wb:   Support for fast ethernet adapters based on the Winbond W89C840F chip.
  #       Note: this is not the same as the Winbond W89C940F, which is a
  #       NE2000 clone.
  # wi:   Lucent WaveLAN/IEEE 802.11 PCMCIA adapters. Note: this supports both
  #       the PCMCIA and ISA cards: the ISA card is really a PCMCIA to ISA
  #       bridge with a PCMCIA adapter plugged into it.
  # xe:   Xircom/Intel EtherExpress Pro100/16 PC Card ethernet controller,
  #       Accton Fast EtherCard-16, Compaq Netelligent 10/100 PC Card,
  #       Toshiba 10/100 Ethernet PC Card, Xircom 16-bit Ethernet + Modem 56
  # xl:   Support for the 3Com 3c900, 3c905, 3c905B and 3c905C (Fast)
  #       Etherlink XL cards and integrated controllers.  This includes the
  #       integrated 3c905B-TX chips in certain Dell Optiplex and Dell
  #       Precision desktop machines and the integrated 3c905-TX chips
  #       in Dell Latitude laptop docking stations.
  #       Also supported: 3Com 3c980(C)-TX, 3Com 3cSOHO100-TX, 3Com 3c450-TX
  
  # Order for ISA/EISA devices is important here
  
  device          cm
  hint.cm.0.at="isa"
  hint.cm.0.port="0x2e0"
  hint.cm.0.irq="9"
  hint.cm.0.maddr="0xdc000"
  device          cs
  hint.cs.0.at="isa"
  hint.cs.0.port="0x300"
  device          ep
  device          ex
  device          fe
  hint.fe.0.at="isa"
  hint.fe.0.port="0x300"
  device          fea
  device          sn
  hint.sn.0.at="isa"
  hint.sn.0.port="0x300"
  hint.sn.0.irq="10"
  device          an
  device          awi
  device          cnw
  device          wi
  device          xe
  
  # PCI Ethernet NICs that use the common MII bus controller code.
  device          dc              # DEC/Intel 21143 and various workalikes
  device          fxp             # Intel EtherExpress PRO/100B (82557, 82558)
  hint.fxp.0.prefer_iomap="0"
  device          my              # Myson Fast Ethernet (MTD80X, MTD89X)
  device          rl              # RealTek 8129/8139
  device          pcn             # AMD Am79C97x PCI 10/100 NICs
  device          sf              # Adaptec AIC-6915 (``Starfire'')
  device          sbsh            # Granch SBNI16 SHDSL modem
  device          sis             # Silicon Integrated Systems SiS 900/SiS 7016
  device          ste             # Sundance ST201 (D-Link DFE-550TX)
  device          tl              # Texas Instruments ThunderLAN
  device          tx              # SMC EtherPower II (83c170 ``EPIC'')
  device          vr              # VIA Rhine, Rhine II
  device          wb              # Winbond W89C840F
  device          xl              # 3Com 3c90x (``Boomerang'', ``Cyclone'')
  
  # PCI Ethernet NICs.
  device          de              # DEC/Intel DC21x4x (``Tulip'')
  device          txp             # 3Com 3cR990 (``Typhoon'')
  device          vx              # 3Com 3c590, 3c595 (``Vortex'')
  
  # PCI Gigabit & FDDI NICs.
  device          bge
  device          gx
  device          lge
  device          nge
  device          sk
  device          ti
  device          fpa
  
  # Use "private" jumbo buffers allocated exclusively for the ti(4) driver.
  # This option is incompatible with the TI_JUMBO_HDRSPLIT option below.
  #options        TI_PRIVATE_JUMBOS
  # Turn on the header splitting option for the ti(4) driver firmware.  This
  # only works for Tigon II chips, and has no effect for Tigon I chips.
  options         TI_JUMBO_HDRSPLIT
  
  # These two options allow manipulating the mbuf cluster size and mbuf size,
  # respectively.  Be very careful with NIC driver modules when changing
  # these from their default values, because that can potentially cause a
  # mismatch between the mbuf size assumed by the kernel and the mbuf size
  # assumed by a module.  The only driver that currently has the ability to
  # detect a mismatch is ti(4).
  options         MCLSHIFT=12     # mbuf cluster shift in bits, 12 == 4KB
  options         MSIZE=512       # mbuf size in bytes
  
  #
  # ATM related options (Cranor version)
  # (note: this driver cannot be used with the HARP ATM stack)
  #
  # The `en' device provides support for Efficient Networks (ENI)
  # ENI-155 PCI midway cards, and the Adaptec 155Mbps PCI ATM cards (ANA-59x0).
  #
  # atm device provides generic atm functions and is required for
  # atm devices.
  # NATM enables the netnatm protocol family that can be used to
  # bypass TCP/IP.
  #
  # the current driver supports only PVC operations (no atm-arp, no multicast).
  # for more details, please read the original documents at
  # http://www.ccrc.wustl.edu/pub/chuck/tech/bsdatm/bsdatm.html
  #
  device          atm
  device          en
  options         NATM                    #native ATM
  
  #
  # Audio drivers: `pcm', `sbc', `gusc'
  #
  # pcm: PCM audio through various sound cards.
  #
  # This has support for a large number of new audio cards, based on
  # CS423x, OPTi931, Yamaha OPL-SAx, and also for SB16, GusPnP.
  # For more information about this driver and supported cards,
  # see the pcm.4 man page.
  #
  # The flags of the device tells the device a bit more info about the
  # device that normally is obtained through the PnP interface.
  #       bit  2..0   secondary DMA channel;
  #       bit  4      set if the board uses two dma channels;
  #       bit 15..8   board type, overrides autodetection; leave it
  #                   zero if don't know what to put in (and you don't,
  #                   since this is unsupported at the moment...).
  #
  # Supported cards include:
  # Creative SoundBlaster ISA PnP/non-PnP
  # Supports ESS and Avance ISA chips as well.
  # Gravis UltraSound ISA PnP/non-PnP
  # Crystal Semiconductor CS461x/428x PCI
  # Neomagic 256AV (ac97)
  # Most of the more common ISA/PnP sb/mss/ess compatable cards.
  
  device          pcm
  
  # For non-pnp sound cards with no bridge drivers only:
  hint.pcm.0.at="isa"
  hint.pcm.0.irq="10"
  hint.pcm.0.drq="1"
  hint.pcm.0.flags="0x0"
  
  #
  # midi: MIDI interfaces and synthesizers
  #
  
  device          midi
  
  # For non-pnp sound cards with no bridge drivers:
  hint.midi.0.at="isa"
  hint.midi.0.irq="5"
  hint.midi.0.flags="0x0"
  
  # For serial ports (this example configures port 2):
  # TODO: implement generic tty-midi interface so that we can use
  #       other uarts.
  hint.midi.0.at="isa"
  hint.midi.0.port="0x2F8"
  hint.midi.0.irq="3"
  
  #
  # seq: MIDI sequencer
  #
  
  device          seq
  
  # The bridge drivers for sound cards.  These can be separately configured
  # for providing services to the likes of new-midi.
  # When used with 'device pcm' they also provide pcm sound services.
  #
  # sbc:  Creative SoundBlaster ISA PnP/non-PnP
  #       Supports ESS and Avance ISA chips as well.
  # gusc: Gravis UltraSound ISA PnP/non-PnP
  # csa:  Crystal Semiconductor CS461x/428x PCI
  
  # For non-PnP cards:
  device          sbc
  hint.sbc.0.at="isa"
  hint.sbc.0.port="0x220"
  hint.sbc.0.irq="5"
  hint.sbc.0.drq="1"
  hint.sbc.0.flags="0x15"
  device          gusc
  hint.gusc.0.at="isa"
  hint.gusc.0.port="0x220"
  hint.gusc.0.irq="5"
  hint.gusc.0.drq="1"
  hint.gusc.0.flags="0x13"
  
  #
  # Miscellaneous hardware:
  #
  # scd: Sony CD-ROM using proprietary (non-ATAPI) interface
  # mcd: Mitsumi CD-ROM using proprietary (non-ATAPI) interface
  # meteor: Matrox Meteor video capture board
  # bktr: Brooktree bt848/848a/849a/878/879 video capture and TV Tuner board
  # cy: Cyclades serial driver
  # joy: joystick (including IO DATA PCJOY PC Card joystick)
  # rc: RISCom/8 multiport card
  # rp: Comtrol Rocketport(ISA/PCI) - single card
  # si: Specialix SI/XIO 4-32 port terminal multiplexor
  # nmdm: nullmodem terminal driver (see nmdm(4))
  
  # Notes on the Comtrol Rocketport driver:
  #
  # The exact values used for rp0 depend on how many boards you have
  # in the system.  The manufacturer's sample configs are listed as:
  #
  #               device  rp      # core driver support
  #
  #   Comtrol Rocketport ISA single card
  #               hint.rp.0.at="isa"
  #               hint.rp.0.port="0x280"
  #
  #   If instead you have two ISA cards, one installed at 0x100 and the
  #   second installed at 0x180, then you should add the following to
  #   your kernel probe hints:
  #               hint.rp.0.at="isa"
  #               hint.rp.0.port="0x100"
  #               hint.rp.1.at="isa"
  #               hint.rp.1.port="0x180"
  #
  #   For 4 ISA cards, it might be something like this:
  #               hint.rp.0.at="isa"
  #               hint.rp.0.port="0x180"
  #               hint.rp.1.at="isa"
  #               hint.rp.1.port="0x100"
  #               hint.rp.2.at="isa"
  #               hint.rp.2.port="0x340"
  #               hint.rp.3.at="isa"
  #               hint.rp.3.port="0x240"
  #
  #   For PCI cards, you need no hints.
  
  # Mitsumi CD-ROM
  device          mcd      
  hint.mcd.0.at="isa"
  hint.mcd.0.port="0x300"
  # for the Sony CDU31/33A CDROM
  device          scd
  hint.scd.0.at="isa"
  hint.scd.0.port="0x230"
  device          joy                     # PnP aware, hints for nonpnp only
  hint.joy.0.at="isa"
  hint.joy.0.port="0x201"
  device          rc
  hint.rc.0.at="isa"
  hint.rc.0.port="0x220"
  hint.rc.0.irq="12"
  device          rp
  hint.rp.0.at="isa"
  hint.rp.0.port="0x280"
  device          si
  options         SI_DEBUG
  hint.si.0.at="isa"
  hint.si.0.maddr="0xd0000"
  hint.si.0.irq="12"
  device          nmdm
  
  #
  # The `meteor' device is a PCI video capture board. It can also have the
  # following options:
  #   options METEOR_ALLOC_PAGES=xxx      preallocate kernel pages for data entry
  #       figure (ROWS*COLUMN*BYTES_PER_PIXEL*FRAME+PAGE_SIZE-1)/PAGE_SIZE
  #   options METEOR_DEALLOC_PAGES        remove all allocated pages on close(2)
  #   options METEOR_DEALLOC_ABOVE=xxx    remove all allocated pages above the
  #       specified amount. If this value is below the allocated amount no action
  #       taken
  #   options METEOR_SYSTEM_DEFAULT={METEOR_PAL|METEOR_NTSC|METEOR_SECAM}, used
  #       for initialization of fps routine when a signal is not present.
  #
  # The 'bktr' device is a PCI video capture device using the Brooktree
  # bt848/bt848a/bt849a/bt878/bt879 chipset. When used with a TV Tuner it forms a
  # TV card, eg Miro PC/TV, Hauppauge WinCast/TV WinTV, VideoLogic Captivator,
  # Intel Smart Video III, AverMedia, IMS Turbo, FlyVideo.
  #
  # options       OVERRIDE_CARD=xxx
  # options       OVERRIDE_TUNER=xxx
  # options       OVERRIDE_MSP=1
  # options       OVERRIDE_DBX=1
  # These options can be used to override the auto detection
  # The current values for xxx are found in src/sys/dev/bktr/bktr_card.h
  # Using sysctl(8) run-time overrides on a per-card basis can be made
  #
  # options       BROOKTREE_SYSTEM_DEFAULT=BROOKTREE_PAL
  # or
  # options       BROOKTREE_SYSTEM_DEFAULT=BROOKTREE_NTSC
  # Specifes the default video capture mode.
  # This is required for Dual Crystal (28&35Mhz) boards where PAL is used
  # to prevent hangs during initialisation.  eg VideoLogic Captivator PCI.
  #
  # options       BKTR_USE_PLL
  # PAL or SECAM users who have a 28Mhz crystal (and no 35Mhz crystal)
  # must enable PLL mode with this option. eg some new Bt878 cards.
  #
  # options       BKTR_GPIO_ACCESS
  # This enable IOCTLs which give user level access to the GPIO port.
  #
  # options       BKTR_NO_MSP_RESET
  # Prevents the MSP34xx reset. Good if you initialise the MSP in another OS first
  #
  # options       BKTR_430_FX_MODE
  # Switch Bt878/879 cards into Intel 430FX chipset compatibility mode.
  #
  # options       BKTR_SIS_VIA_MODE
  # Switch Bt878/879 cards into SIS/VIA chipset compatibility mode which is
  # needed for some old SiS and VIA chipset motherboards.
  # This also allows Bt878/879 chips to work on old OPTi (<1997) chipset
  # motherboards and motherboards with bad or incomplete PCI 2.1 support.
  # As a rough guess, old = before 1998
  #
  
  device          meteor  1
  
  #
  # options       BKTR_USE_FREEBSD_SMBUS
  # Compile with FreeBSD SMBus implementation
  #
  # Brooktree driver has been ported to the new I2C framework. Thus,
  # you'll need to have the following 3 lines in the kernel config.
  #     device smbus
  #     device iicbus
  #     device iicbb
  #     device iicsmb
  # The iic and smb devices are only needed if you want to control other
  # I2C slaves connected to the external connector of some cards.
  #
  device          bktr
  
  #
  # PC Card/PCMCIA
  # (OLDCARD)
  #
  # card: pccard slots
  # pcic: isa/pccard bridge
  #device         pcic
  #hint.pcic.0.at="isa"
  #hint.pcic.1.at="isa"
  #device         card    1
  
  #
  # PC Card/PCMCIA and Cardbus
  # (NEWCARD)
  #
  # Note that NEWCARD and OLDCARD are incompatible.  Do not use both at the same
  # time.
  #
  # pccbb: pci/cardbus bridge implementing YENTA interface
  # pccard: pccard slots
  # cardbus: cardbus slots
  device          cbb
  device          pccard
  device          cardbus
  #device         pcic            ISA attachment currently busted
  #hint.pcic.0.at="isa"
  #hint.pcic.1.at="isa"
  
  #
  # SMB bus
  #
  # System Management Bus support is provided by the 'smbus' device.
  # Access to the SMBus device is via the 'smb' device (/dev/smb*),
  # which is a child of the 'smbus' device.
  #
  # Supported devices:
  # smb           standard io through /dev/smb*
  #
  # Supported SMB interfaces:
  # iicsmb        I2C to SMB bridge with any iicbus interface
  # bktr          brooktree848 I2C hardware interface
  # intpm         Intel PIIX4 (82371AB, 82443MX) Power Management Unit
  # alpm          Acer Aladdin-IV/V/Pro2 Power Management Unit
  # ichsmb        Intel ICH SMBus controller chips (82801AA, 82801AB, 82801BA)
  # viapm         VIA VT82C586B/596B/686A and VT8233 Power Management Unit 
  # amdpm         AMD 756 Power Management Unit
  # nfpm          NVIDIA nForce Power Management Unit
  #
  device          smbus           # Bus support, required for smb below.
  
  device          intpm
  device          alpm
  device          ichsmb
  device          viapm
  device          amdpm
  device          nfpm
  
  device          smb
  
  #
  # I2C Bus
  #
  # Philips i2c bus support is provided by the `iicbus' device.
  #
  # Supported devices:
  # ic    i2c network interface
  # iic   i2c standard io
  # iicsmb i2c to smb bridge. Allow i2c i/o with smb commands.
  #
  # Supported interfaces:
  # bktr  brooktree848 I2C software interface
  #
  # Other:
  # iicbb generic I2C bit-banging code (needed by lpbb, bktr)
  #
  device          iicbus          # Bus support, required for ic/iic/iicsmb below.
  device          iicbb
  
  device          ic
  device          iic
  device          iicsmb          # smb over i2c bridge
  
  # Parallel-Port Bus
  #
  # Parallel port bus support is provided by the `ppbus' device.
  # Multiple devices may be attached to the parallel port, devices
  # are automatically probed and attached when found.
  #
  # Supported devices:
  # vpo   Iomega Zip Drive
  #       Requires SCSI disk support ('scbus' and 'da'), best
  #       performance is achieved with ports in EPP 1.9 mode.
  # lpt   Parallel Printer
  # plip  Parallel network interface
  # ppi   General-purpose I/O ("Geek Port") + IEEE1284 I/O
  # pps   Pulse per second Timing Interface
  # lpbb  Philips official parallel port I2C bit-banging interface
  #
  # Supported interfaces:
  # ppc   ISA-bus parallel port interfaces.
  #
  
  options         PPC_PROBE_CHIPSET # Enable chipset specific detection
                                    # (see flags in ppc(4))
  options         DEBUG_1284      # IEEE1284 signaling protocol debug
  options         PERIPH_1284     # Makes your computer act as an IEEE1284
                                  # compliant peripheral
  options         DONTPROBE_1284  # Avoid boot detection of PnP parallel devices
  options         VP0_DEBUG       # ZIP/ZIP+ debug
  options         LPT_DEBUG       # Printer driver debug
  options         PPC_DEBUG       # Parallel chipset level debug
  options         PLIP_DEBUG      # Parallel network IP interface debug
  options         PCFCLOCK_VERBOSE         # Verbose pcfclock driver
  options         PCFCLOCK_MAX_RETRIES=5   # Maximum read tries (default 10)
  
  device          ppc
  hint.ppc.0.at="isa"
  hint.ppc.0.irq="7"
  device          ppbus
  device          vpo
  device          lpt
  device          plip
  device          ppi
  device          pps
  device          lpbb
  device          pcfclock
  
  # Kernel BOOTP support
  
  options         BOOTP           # Use BOOTP to obtain IP address/hostname
                                  # Requires NFSCLIENT and NFS_ROOT
  options         BOOTP_NFSROOT   # NFS mount root filesystem using BOOTP info
  options         BOOTP_NFSV3     # Use NFS v3 to NFS mount root
  options         BOOTP_COMPAT    # Workaround for broken bootp daemons.
  options         BOOTP_WIRED_TO=fxp0 # Use interface fxp0 for BOOTP
  
  #
  # Add tie-ins for a hardware watchdog.  This only enable the hooks;
  # the user must still supply the actual driver.
  #
  options         HW_WDOG
  
  #
  # Disable swapping of upages and stack pages.  This option removes all
  # code which actually performs swapping, so it's not possible to turn
  # it back on at run-time.
  #
  # This is sometimes usable for systems which don't have any swap space
  # (see also sysctls "vm.defer_swapspace_pageouts" and
  # "vm.disable_swapspace_pageouts")
  #
  #options        NO_SWAPPING
  
  # Set the number of sf_bufs to allocate. sf_bufs are virtual buffers
  # for sendfile(2) that are used to map file VM pages, and normally
  # default to a quantity that is roughly 16*MAXUSERS+512. You would
  # typically want about 4 of these for each simultaneous file send.
  #
  options         NSFBUFS=1024
  
  #
  # Enable extra debugging code for locks.  This stores the filename and
  # line of whatever acquired the lock in the lock itself, and change a
  # number of function calls to pass around the relevant data.  This is
  # not at all useful unless you are debugging lock code.  Also note
  # that it is likely to break e.g. fstat(1) unless you recompile your
  # userland with -DDEBUG_LOCKS as well.
  #
  options         DEBUG_LOCKS
  
  
  #####################################################################
  # USB support
  # UHCI controller
  device          uhci
  # OHCI controller
  device          ohci
  # EHCI controller
  device          ehci
  # General USB code (mandatory for USB)
  device          usb
  #
  # USB Double Bulk Pipe devices
  device          udbp
  # Generic USB device driver
  device          ugen
  # Human Interface Device (anything with buttons and dials)
  device          uhid
  # USB keyboard
  device          ukbd
  # USB printer
  device          ulpt
  # USB Iomega Zip 100 Drive (Requires scbus and da)
  device          umass
  # USB modem support
  device          umodem
  # USB mouse
  device          ums
  # Diamond Rio 500 Mp3 player
  device          urio
  # USB scanners
  device          uscanner
  # USB serial support
  device          ucom
  # USB support for serial adapters based on the FT8U100AX and FT8U232AM
  device          uftdi
  # USB support for Prolific PL-2303 serial adapters
  device          uplcom
  # USB support for Belkin F5U103 and compatible serial adapters
  device          ubsa
  # USB serial support for DDI pocket's PHS
  device          uvscom
  # USB Visor and Palm devices
  device          uvisor
  
  # USB Fm Radio
  device          ufm
  #
  # ADMtek USB ethernet. Supports the LinkSys USB100TX,
  # the Billionton USB100, the Melco LU-ATX, the D-Link DSB-650TX
  # and the SMC 2202USB. Also works with the ADMtek AN986 Pegasus
  # eval board.
  device          aue
  #
  # CATC USB-EL1201A USB ethernet. Supports the CATC Netmate
  # and Netmate II, and the Belkin F5U111.
  device          cue
  #
  # Kawasaki LSI ethernet. Supports the LinkSys USB10T,
  # Entrega USB-NET-E45, Peracom Ethernet Adapter, the
  # 3Com 3c19250, the ADS Technologies USB-10BT, the ATen UC10T,
  # the Netgear EA101, the D-Link DSB-650, the SMC 2102USB
  # and 2104USB, and the Corega USB-T.
  device          kue
  #
  # RealTek RTL8150 USB to fast ethernet. Supports the Melco LUA-KTX
  # and the GREEN HOUSE GH-USB100B.
  device          rue
  
  # debugging options for the USB subsystem
  #
  options         USB_DEBUG
  
  # options for ukbd:
  options         UKBD_DFLT_KEYMAP        # specify the built-in keymap
  makeoptions     UKBD_DFLT_KEYMAP=it.iso
  
  # options for uvscom:
  options         UVSCOM_DEFAULT_OPKTSIZE=8       # default output packet size
  
  #####################################################################
  # Firewire support
  
  device          firewire        # Firewire bus code
  device          sbp             # SCSI over Firewire (Requires scbus and da)
  device          fwe             # Ethernet over Firewire (non-standard!)
  
  #####################################################################
  # crypto subsystem
  #
  # This is a port of the openbsd crypto framework.  Include this when
  # configuring FAST_IPSEC and when you have a h/w crypto device to accelerate
  # user applications that link to openssl.
  #
  # Drivers are ports from openbsd with some simple enhancements that have
  # been fed back to openbsd.
  
  device          crypto          # core crypto support
  device          cryptodev       # /dev/crypto for access to h/w
  
  device          rndtest         # FIPS 140-2 entropy tester
  
  device          hifn            # Hifn 7951, 7781, etc.
  options         HIFN_DEBUG      # enable debugging support: hw.hifn.debug
  options         HIFN_RNDTEST    # enable rndtest support
  
  device          ubsec           # Broadcom 5501, 5601, 58xx
  options         UBSEC_DEBUG     # enable debugging support: hw.ubsec.debug
  options         UBSEC_RNDTEST   # enable rndtest support
  
  #####################################################################
  
  
  #
  # Embedded system options:
  #
  # An embedded system might want to run something other than init.
  options         INIT_PATH=/sbin/init:/stand/sysinstall
  
  # Debug options
  options         BUS_DEBUG       # enable newbus debugging
  options         DEBUG_VFS_LOCKS # enable vfs lock debugging
  
  #####################################################################
  # SYSV IPC KERNEL PARAMETERS
  #
  # Maximum number of entries in a semaphore map.
  options         SEMMAP=31
  
  # Maximum number of System V semaphores that can be used on the system at
  # one time. 
  options         SEMMNI=11
  
  # Total number of semaphores system wide
  options         SEMMNS=61
  
  # Total number of undo structures in system
  options         SEMMNU=31
  
  # Maximum number of System V semaphores that can be used by a single process
  # at one time. 
  options         SEMMSL=61
  
  # Maximum number of operations that can be outstanding on a single System V
  # semaphore at one time. 
  options         SEMOPM=101
  
  # Maximum number of undo operations that can be outstanding on a single
  # System V semaphore at one time. 
  options         SEMUME=11
  
  # Maximum number of shared memory pages system wide.
  options         SHMALL=1025
  
  # Maximum size, in bytes, of a single System V shared memory region. 
  options         SHMMAX=(SHMMAXPGS*PAGE_SIZE+1)
  options         SHMMAXPGS=1025
  
  # Minimum size, in bytes, of a single System V shared memory region. 
  options         SHMMIN=2
  
  # Maximum number of shared memory regions that can be used on the system
  # at one time. 
  options         SHMMNI=33
  
  # Maximum number of System V shared memory regions that can be attached to
  # a single process at one time. 
  options         SHMSEG=9
  
  # Set the amount of time (in seconds) the system will wait before
  # rebooting automatically when a kernel panic occurs.  If set to (-1),
  # the system will wait indefinitely until a key is pressed on the
  # console.
  options         PANIC_REBOOT_WAIT_TIME=16
  
  # Attempt to bypass the buffer cache and put data directly into the
  # userland buffer for read operation when O_DIRECT flag is set on the
  # file.  Both offset and length of the read operation must be
  # multiples of the physical media sector size. 
  #
  #options                DIRECTIO
  
  # Specify a lower limit for the number of swap I/O buffers.  They are
  # (among other things) used when bypassing the buffer cache due to
  # DIRECTIO kernel option enabled and O_DIRECT flag set on file.
  #
  #options                NSWBUF_MIN=120
  
  #####################################################################
  
  # More undocumented options for linting.
  # Note that documenting these are not considered an affront.
  
  options         CAM_DEBUG_DELAY
  
  # VFS cluster debugging.
  options         CLUSTERDEBUG
  
  options         DEBUG
  
  # Kernel filelock debugging.
  options         LOCKF_DEBUG
  
  # System V compatible message queues
  # Please note that the values provided here are used to test kernel
  # building.  The defaults in the sources provide almost the same numbers.
  # MSGSSZ must be a power of 2 between 8 and 1024.
  options         MSGMNB=2049     # Max number of chars in queue
  options         MSGMNI=41       # Max number of message queue identifiers
  options         MSGSEG=2049     # Max number of message segments
  options         MSGSSZ=16       # Size of a message segment
  options         MSGTQL=41       # Max number of messages in system
  
  options         NBUF=512        # Number of buffer headers
  
  options         NMBCLUSTERS=1024        # Number of mbuf clusters
  
  options         SCSI_NCR_DEBUG
  options         SCSI_NCR_MAX_SYNC=10000
  options         SCSI_NCR_MAX_WIDE=1
  options         SCSI_NCR_MYADDR=7
  
  options         SC_DEBUG_LEVEL=5        # Syscons debug level
  options         SC_RENDER_DEBUG # syscons rendering debugging
  
  options         SHOW_BUSYBUFS   # List buffers that prevent root unmount
  options         SLIP_IFF_OPTS
  options         VFS_BIO_DEBUG   # VFS buffer I/O debugging
  
  options         KSTACK_MAX_PAGES=32 # Maximum pages to give the kernel stack
  
  # Yet more undocumented options for linting.
  options         AAC_DEBUG
  options         ACD_DEBUG
  options         ACPI_MAX_THREADS=1
  #!options       ACPI_NO_SEMAPHORES
  # Broken:
  ##options       ASR_MEASURE_PERFORMANCE
  options         AST_DEBUG
  options         ATAPI_DEBUG
  options         ATA_DEBUG
  # BKTR_ALLOC_PAGES has no effect except to cause warnings, and
  # BROOKTREE_ALLOC_PAGES hasn't actually been superseded by it, since the
  # driver still mostly spells this option BROOKTREE_ALLOC_PAGES.
  ##options       BKTR_ALLOC_PAGES=(217*4+1)
  options         BROOKTREE_ALLOC_PAGES=(217*4+1)
  options         MAXFILES=999
  # METEOR_TEST_VIDEO has no effect since meteor is broken.
  options         METEOR_TEST_VIDEO
  options         NDEVFSINO=1025
  options         NDEVFSOVERFLOW=32769
  
  # Yet more undocumented options for linting.
  options         VGA_DEBUG

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