使用环境：FreeBSD7.4 amd64 速龙2 250 内存4G 硬盘2T
内核编译目的：比起通用内核，按照当前机器编译内核后，可以去除不需要的硬件驱动预置，节省内存，提高启动速度。
编译内核前，要安装src下base和sys
这一节看使用手册就能完全搞定，在此省略。
这里主要说一下内容的取舍。
当机不需要SCSI，不需要RAID，没有ISA设备，不要USB设备，不要火线，不要无线。
#
# GENERIC -- Generic kernel configuration file for FreeBSD/amd64
#
# For more information on this file, please read the handbook section on
# Kernel Configuration Files:
#
# http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig-c...
#
# The handbook is also available locally in /usr/share/doc/handbook
# if you've installed the doc distribution, otherwise always see the
# FreeBSD World Wide Web server (http://www.FreeBSD.org/) for the
# latest information.
#
# An exhaustive list of options and more detailed explanations of the
# device lines is also present in the ../../conf/NOTES and NOTES files.
# If you are in doubt as to the purpose or necessity of a line, check first
# in NOTES.
#
# $FreeBSD: src/sys/amd64/conf/GENERIC,v 1.484.2.25.2.1 2010/12/21 17:10:29 kensmith Exp $
cpu HAMMER（这个不需要变）
ident 你的内核名字
# To statically compile in device wiring instead of /boot/device.hints
#hints "GENERIC.hints" # Default places to look for devices.
#makeoptions DEBUG=-g # Build kernel with gdb(1) debug symbols
options SCHED_ULE # ULE scheduler此项要保留
options PREEMPTION # Enable kernel thread preemption
options INET # InterNETworking
#options INET6 # IPv6 communications protocols
options SCTP # Stream Control Transmission Protocol
options FFS # Berkeley Fast Filesystem
options SOFTUPDATES # Enable FFS soft updates support
options UFS_ACL # Support for access control lists
options UFS_DIRHASH # Improve performance on big directories
options UFS_GJOURNAL # Enable gjournal-based UFS journaling
options MD_ROOT # MD is a potential root device
#options NFSCLIENT # Network Filesystem Client
#options NFSSERVER # Network Filesystem Server
#options NFSLOCKD # Network Lock Manager
#options NFS_ROOT # NFS usable as /, requires NFSCLIENT
#options MSDOSFS # MSDOS Filesystem
options CD9660 # ISO 9660 Filesystem
options PROCFS # Process filesystem (requires PSEUDOFS)
options PSEUDOFS # Pseudo-filesystem framework
options GEOM_PART_GPT # GUID Partition Tables.
options GEOM_LABEL # Provides labelization
options COMPAT_43TTY # BSD 4.3 TTY compat [KEEP THIS!]
options COMPAT_IA32 # Compatible with i386 binaries
options COMPAT_FREEBSD4 # Compatible with FreeBSD4
options COMPAT_FREEBSD5 # Compatible with FreeBSD5
options COMPAT_FREEBSD6 # Compatible with FreeBSD6
#options SCSI_DELAY=5000 # Delay (in ms) before probing SCSI
options KTRACE # ktrace(1) support
options STACK # stack(9) support
options SYSVSHM # SYSV-style shared memory
options SYSVMSG # SYSV-style message queues
options SYSVSEM # SYSV-style semaphores
#options P1003_1B_SEMAPHORES # POSIX-style semaphores
#options _KPOSIX_PRIORITY_SCHEDULING # POSIX P1003_1B real-time extensions
options KBD_INSTALL_CDEV # install a CDEV entry in /dev
options ADAPTIVE_GIANT # Giant mutex is adaptive.
options STOP_NMI # Stop CPUS using NMI instead of IPI
options AUDIT # Security event auditing
#options KDTRACE_FRAME # Ensure frames are compiled in
#options KDTRACE_HOOKS # Kernel DTrace hooks
options INCLUDE_CONFIG_FILE # Include this file in kernel
# Make an SMP-capable kernel by default
options SMP # Symmetric MultiProcessor Kernel多核处理器都需要
# CPU frequency control
#device cpufreq
# Bus support.
device acpi 需保留
device pci
# Floppy drives
#device fdc
# ATA and ATAPI devices
device ata
device atadisk # ATA disk drives
#device ataraid # ATA RAID drives
device atapicd # ATAPI CDROM drives
#device atapifd # ATAPI floppy drives
#device atapist # ATAPI tape drives
options ATA_STATIC_ID # Static device numbering
# SCSI Controllers
#device ahc # AHA2940 and onboard AIC7xxx devices
#options AHC_REG_PRETTY_PRINT # Print register bitfields in debug
# output. Adds ~128k to driver.
#device ahd # AHA39320/29320 and onboard AIC79xx devices
#options AHD_REG_PRETTY_PRINT # Print register bitfields in debug
# output. Adds ~215k to driver.
#device amd # AMD 53C974 (Tekram DC-390(T))
#device hptiop # Highpoint RocketRaid 3xxx series
#device isp # Qlogic family
##device ispfw # Firmware for QLogic HBAs- normally a module
#device mpt # LSI-Logic MPT-Fusion
##device ncr # NCR/Symbios Logic
#device sym # NCR/Symbios Logic (newer chipsets + those of `ncr')
#device trm # Tekram DC395U/UW/F DC315U adapters
#device adv # Advansys SCSI adapters
#device adw # Advansys wide SCSI adapters
#device aic # Adaptec 15[012]x SCSI adapters, AIC-6[23]60.
#device bt # Buslogic/Mylex MultiMaster SCSI adapters
# SCSI peripherals
device scbus # SCSI bus (required for SCSI)用不上SCSI也需保留
#device ch # SCSI media changers
#device da # Direct Access (disks)
#device sa # Sequential Access (tape etc)
#device cd # CD
#device pass # Passthrough device (direct SCSI access)
#device ses # SCSI Environmental Services (and SAF-TE)
# RAID controllers interfaced to the SCSI subsystem
#device amr # AMI MegaRAID
#device arcmsr # Areca SATA II RAID
#device ciss # Compaq Smart RAID 5*
#device dpt # DPT Smartcache III, IV - See NOTES for options
#device hptmv # Highpoint RocketRAID 182x
#device hptrr # Highpoint RocketRAID 17xx, 22xx, 23xx, 25xx
#device iir # Intel Integrated RAID
#device ips # IBM (Adaptec) ServeRAID
#device mly # Mylex AcceleRAID/eXtremeRAID
#device twa # 3ware 9000 series PATA/SATA RAID
# RAID controllers
#device aac # Adaptec FSA RAID
#device aacp # SCSI passthrough for aac (requires CAM)
#device ida # Compaq Smart RAID
#device mfi # LSI MegaRAID SAS
#device mlx # Mylex DAC960 family
#XXX pointer/int warnings
##device pst # Promise Supertrak SX6000
#device twe # 3ware ATA RAID
# atkbdc0 controls both the keyboard and the PS/2 mouse
device atkbdc # AT keyboard controller
device atkbd # AT keyboard
device psm # PS/2 mouse
device kbdmux # keyboard multiplexer
device vga # VGA video card driver
device splash # Splash screen and screen saver support
# syscons is the default console driver, resembling an SCO console
device sc 此项需保留
#device agp # support several AGP chipsets
# PCCARD (PCMCIA) support
# PCMCIA and cardbus bridge support
#device cbb # cardbus (yenta) bridge
#device pccard # PC Card (16-bit) bus
#device cardbus # CardBus (32-bit) bus
# Serial (COM) ports
#device sio # 8250, 16[45]50 based serial ports
#device uart # Generic UART driver
# Parallel port
device ppc
device ppbus # Parallel port bus (required)
#device lpt # Printer
device plip # TCP/IP over parallel
device ppi # Parallel port interface device
##device vpo # Requires scbus and da
# If you've got a "dumb" serial or parallel PCI card that is
# supported by the puc(4) glue driver, uncomment the following
# line to enable it (connects to sio, uart and/or ppc drivers):
##device puc
# PCI Ethernet NICs.
#device de # DEC/Intel DC21x4x (``Tulip'')
#device em # Intel PRO/1000 Gigabit Ethernet Family
#device igb # Intel PRO/1000 PCIE Server Gigabit Family
#device ixgbe # Intel PRO/10GbE PCIE Ethernet Family
#device le # AMD Am7900 LANCE and Am79C9xx PCnet
#device txp # 3Com 3cR990 (``Typhoon'')
#device vx # 3Com 3c590, 3c595 (``Vortex'')
# PCI Ethernet NICs that use the common MII bus controller code.
# NOTE: Be sure to keep the 'device miibus' line in order to use these NICs!
device miibus # MII bus support 此项需保留
#device age # Attansic/Atheros L1 Gigabit Ethernet
device alc # Atheros AR8131/AR8132 Ethernet
#device ale # Atheros AR8121/AR8113/AR8114 Ethernet
#device bce # Broadcom BCM5706/BCM5708 Gigabit Ethernet
#device bfe # Broadcom BCM440x 10/100 Ethernet
#device bge # Broadcom BCM570xx Gigabit Ethernet
device dc # DEC/Intel 21143 and various workalikes
#device et # Agere ET1310 10/100/Gigabit Ethernet
#device fxp # Intel EtherExpress PRO/100B (82557, 82558)
#device jme # JMicron JMC250 Gigabit/JMC260 Fast Ethernet
#device lge # Level 1 LXT1001 gigabit Ethernet
#device msk # Marvell/SysKonnect Yukon II Gigabit Ethernet
#device nfe # nVidia nForce MCP on-board Ethernet
#device nge # NatSemi DP83820 gigabit Ethernet
##device nve # nVidia nForce MCP on-board Ethernet Networking
#device pcn # AMD Am79C97x PCI 10/100 (precedence over 'le')
#device re # RealTek 8139C+/8169/8169S/8110S
#device rl # RealTek 8129/8139
#device sf # Adaptec AIC-6915 (``Starfire'')
#device sge # Silicon Integrated Systems SiS190/191
#device sis # Silicon Integrated Systems SiS 900/SiS 7016
#device sk # SysKonnect SK-984x & SK-982x gigabit Ethernet
#device ste # Sundance ST201 (D-Link DFE-550TX)
#device ti # Alteon Networks Tigon I/II gigabit Ethernet
#device tl # Texas Instruments ThunderLAN
#device tx # SMC EtherPower II (83c170 ``EPIC'')
#device vge # VIA VT612x gigabit Ethernet
#device vr # VIA Rhine, Rhine II
#device wb # Winbond W89C840F
#device xl # 3Com 3c90x (``Boomerang'', ``Cyclone'')
# ISA Ethernet NICs. pccard NICs included.
#device cs # Crystal Semiconductor CS89x0 NIC
# 'device ed' requires 'device miibus'
#device ed # NE[12]000, SMC Ultra, 3c503, DS8390 cards
#device ex # Intel EtherExpress Pro/10 and Pro/10+
#device ep # Etherlink III based cards
#device fe # Fujitsu MB8696x based cards
#device sn # SMC's 9000 series of Ethernet chips
#device xe # Xircom pccard Ethernet
# Wireless NIC cards
#device wlan # 802.11 support
#device wlan_wep # 802.11 WEP support
#device wlan_ccmp # 802.11 CCMP support
#device wlan_tkip # 802.11 TKIP support
#device wlan_amrr # AMRR transmit rate control algorithm
#device wlan_scan_ap # 802.11 AP mode scanning
#device wlan_scan_sta # 802.11 STA mode scanning
#device an # Aironet 4500/4800 802.11 wireless NICs.
#device ath # Atheros pci/cardbus NIC's
#device ath_hal # Atheros HAL (Hardware Access Layer)
#options AH_SUPPORT_AR5416 # enable AR5416 tx/rx descriptors
#device ath_rate_sample # SampleRate tx rate control for ath
#device awi # BayStack 660 and others
#device ral # Ralink Technology RT2500 wireless NICs.
#device wi # WaveLAN/Intersil/Symbol 802.11 wireless NICs.
# Pseudo devices.
device loop # Network loopback
device random # Entropy device
device ether # Ethernet support
#device vlan # 802.1Q VLAN support
#device sl # Kernel SLIP
#device ppp # Kernel PPP
device tun # Packet tunnel.
device pty # Pseudo-ttys (telnet etc)
#device md # Memory "disks"
#device gif # IPv6 and IPv4 tunneling
#device faith # IPv6-to-IPv4 relaying (translation)
device firmware # firmware assist module
# The `bpf' device enables the Berkeley Packet Filter.
# Be aware of the administrative consequences of enabling this!
# Note that 'bpf' is required for DHCP.
device bpf # Berkeley packet filter
# USB support
#device uhci # UHCI PCI->USB interface
#device ohci # OHCI PCI->USB interface
#device ehci # EHCI PCI->USB interface (USB 2.0)
#device usb # USB Bus (required)
#device udbp # USB Double Bulk Pipe devices
#device ugen # Generic
#device uhid # "Human Interface Devices"
#device ukbd # Keyboard
#device ulpt # Printer
#device umass # Disks/Mass storage - Requires scbus and da
#device ums # Mouse
#device urio # Diamond Rio 500 MP3 player
#device uscanner # Scanners
# USB Serial devices
#device ucom # Generic com ttys
#device uark # Technologies ARK3116 based serial adapters
#device ubsa # Belkin F5U103 and compatible serial adapters
#device ubser # BWCT console serial adapters
#device uftdi # For FTDI usb serial adapters
#device uipaq # Some WinCE based devices
#device uplcom # Prolific PL-2303 serial adapters
#device uslcom # SI Labs CP2101/CP2102 serial adapters
#device uvisor # Visor and Palm devices
#device uvscom # USB serial support for DDI pocket's PHS
# USB Ethernet, requires miibus
#device aue # ADMtek USB Ethernet
#device axe # ASIX Electronics USB Ethernet
#device cdce # Generic USB over Ethernet
#device cue # CATC USB Ethernet
#device kue # Kawasaki LSI USB Ethernet
#device rue # RealTek RTL8150 USB Ethernet
# USB Wireless
#device rum # Ralink Technology RT2501USB wireless NICs
#device ural # Ralink Technology RT2500USB wireless NICs
# FireWire support
#device firewire # FireWire bus code
#device sbp # SCSI over FireWire (Requires scbus and da)
#device fwe # Ethernet over FireWire (non-standard!)
#device fwip # IP over FireWire (RFC 2734,3146)
#device dcons # Dumb console driver
#device dcons_crom # Configuration ROM for dcons
完