freebsd編譯核心詳解
阿新 • • 發佈：2019-02-15
以前老聽說編譯核心,覺得特別神氣,呵呵,特別是像FreeBSD這樣自由開發的作業系統,簡直是非常好,能夠自己定製核心,想怎麼弄就怎麼弄,呵呵,能夠提升速度,還能夠保證安全穩定,所以我就試一試怎麼定製核心. (我也是新手，如果文章出現錯誤，請指正！)
我所用的FreeBSD是5.2.1版,現在是比較新的了,我一看我的核心檔案大小:
# ls -l /boot/kernel/kernel
-r-xr-xr-x 1 root wheel 5940286 Feb 24 2004 /boot/kernel.bak/kernel
看來不小呀，5M多，呵呵，我要把它編成 3M左右,呵呵，begin...
一、安裝核心原始碼
要編譯核心，首先必須保證核心的原始碼在，我們看看我們的系統有沒有安裝：
# ls /usr/src/sys
ls: /usr/src/sys: No such file or Directory
證明我們並沒有安裝核心原始碼，好，我們就安裝它。核心原始碼預設是安裝在了/usr/src/sys目錄下的，如果不存在該目錄，那麼證明你沒
有安裝原始碼。
我們先把我們的FreeBSD的安裝光碟放進光碟機，然後在FreeBSD下執行以root身份執行/stand/sysinstall， 選擇Configure，接著是
Distributions， 下來src， 最後sys,回車後能開始安裝了，一般只要幾分鐘就能安裝好，裝好了你就能檢視該資料夾：
# ls /usr/src/sys
Makefile ddb libkern netkey pci
alpha dev modules netnatm posix4
amd64 fs net netncp powerpc
arm geom net80211 netsmb rpc
boot gnu netatalk nfs security
cam i386 netatm nfs4clIEnt sparc64
coda i4b netgraph nfsclient sys
compat ia64 netinet nfsserver tools
conf isa netinet6 opencrypto ufs
contrib isofs netipsec pc98 vm
crypto kern netipx pccard
原始碼安裝好後，我們就可以開始我們的配置核心只旅啦。
二、配置核心檔案
其實我們編譯核心的關鍵就是配置核心檔案，核心配置檔案的目錄是在 /usr/src/sys/i386/conf 下，我們進入改目錄：
# cd /usr/src/sys/i386/conf
# ls
GENERIC GENERIC.hints NOTES PAE
Makefile OLDCARD gethints.awk
核心配置檔案就是GENERIC,我們要配置的就是它,配置包括要開啟那些硬體支援，IPv6支援，網絡卡等等。為了防止我們配置檔案配置後有問題，
我們先把它備份一下：
# cp GENERIC GENERIC.bak
然後我們就用任一編輯器開啟該檔案，可以使用vi，或者ee開啟，我為了方便，就使用ee來開啟：
# ee GENERIC
開啟後就有類似:
# GENERIC -- Generic kernel configuration file for FreeBSD/i386
#
# For more information on this file, please read the handbook section on
# Kernel Configuration Files:
的內容，前面有"#"代表該內容或者選項是註釋，那麼假如我們要去掉什麼選項，就可以在前面加上"#",當然你不需要的選項你也可刪除，但是
我推薦不需要的選項在前面加"#"。
關於配置檔案詳細的修改建議參考FreeBSD中文手冊關於核心配置選項的詳細說明：
http://www.freebsd.org.cn/snap/doc/zh_CN.GB2312/books/handbook/kernelconfig-config.HTML
我的配置檔案是這麼修改的，詳細我就不說明了,請檢視上面的配置檔案參考，應該適合大部分沒有ISA,SCSI,RAID等裝置的機器。
GENERIC核心配置檔案配置：
#########################################################################################
#
# GENERIC -- Generic kernel configuration file for FreeBSD/i386
#
# 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-config.html
#
# The handbook is also available locally in /usr/share/doc/handbook
# if youve 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/i386/conf/GENERIC,v 1.394.2.3 2004/01/26 19:42:11 nectar Exp $
Machine i386
#cpu I486_CPU
#cpu I586_CPU
cpu I686_CPU
ident GENERIC
#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_4BSD #4BSD scheduler
options INET #InterNETworking
#options INET6 #IPv6 communications protocols
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 MD_ROOT #MD is a potential root device
#options NFSCLIENT #Network Filesystem Client
#options NFSSERVER #Network Filesystem Server
#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 COMPAT_43 #Compatible with BSD 4.3 [KEEP THIS!]
options COMPAT_FREEBSD4 #Compatible with FreeBSD4
#options SCSI_DELAY=15000 #Delay (in ms) before probing SCSI
options KTRACE #ktrace(1) support
#options SYSVSHM #SYSV-style shared memory
options SYSVMSG #SYSV-style message queues
options SYSVSEM #SYSV-style semaphores
options _KPOSIX_PRIORITY_SCHEDULING #Posix P1003_1B real-time extensions
options KBD_INSTALL_CDEV # install a CDEV entry in /dev
options AHC_REG_PRETTY_PRINT # Print register bitfields in debug
# output. Adds ~128k to driver.
options AHD_REG_PRETTY_PRINT # Print register bitfields in debug
# output. Adds ~215k to driver.
options PFIL_HOOKS # pfil(9) framework
# Debugging for use in -current
#options DDB #Enable the kernel debugger
#options INVARIANTS #Enable calls of extra sanity checking
#options INVARIANT_SUPPORT #Extra sanity checks of internal structures, required by INVARIANTS
#options WITNESS #Enable checks to detect deadlocks and cycles
#options WITNESS_SKIPSPIN #Dont run witness on spinlocks for speed
# To make an SMP kernel, the next two are needed
#options SMP # Symmetric MultiProcessor Kernel
#device apic # I/O APIC
device isa
device eisa
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 ahb # EISA AHA1742 family
#device ahc # AHA2940 and onboard AIC7xxx devices
#device ahd # AHA39320/29320 and onboard AIC79xx devices
#device amd # AMD 53C974 (Tekram DC-390(T))
#device isp # Qlogic family
#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 aha # Adaptec 154x SCSI adapters
#device aic # Adaptec 15[012]x SCSI adapters, AIC-6[23]60.
#device bt # Buslogic/Mylex MultiMaster SCSI adapters
#device ncv # NCR 53C500
#device nsp # Workbit Ninja SCSI-3
#device stg # TMC 18C30/18C50
# SCSI peripherals
device scbus # SCSI bus (required for SCSI)
#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 asr # DPT SmartRAID V, VI and Adaptec SCSI RAID
#device ciss # Compaq Smart RAID 5*
#device dpt # DPT Smartcache III, IV - See NOTES for options
#device iir # Intel Integrated RAID
#device ips # IBM (Adaptec) ServeRAID
#device mly # Mylex AcceleRAID/eXtremeRAID
# RAID controllers
#device aac # Adaptec FSA RAID
#device aacp # SCSI passthrough for aac (requires CAM)
#device ida # Compaq Smart RAID
#device mlx # Mylex DAC960 family
#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 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
# Enable this for the pcvt (VT220 compatible) console driver
#device vt
#options XSERVER # support for X server on a vt console
#options FAT_CURSOR # start with block cursor
device agp # support several AGP chipsets
# Floating point support - do not disable.
device npx
# Power management support (see NOTES for more options)
#device apm
# Add suspend/resume support for the i8254.
#device pmtimer
# PCCARD (PCMCIA) support
# Pcmcia and cardbus bridge support
#device cbb # cardbus (yenta) bridge
#device pcic # ExCA ISA and PCI bridges
#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
# 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 youve 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 the sio and/or ppc drivers):
#device puc
# PCI Ethernet NICs.
#device de # DEC/Intel DC21x4x (``Tulip)
device em # Intel PRO/1000 adapter Gigabit Ethernet Card
#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
#device bfe # Broadcom BCM440x 10/100 ethernet
#device bge # Broadcom BCM570xx Gigabit Ethernet
#device dc # DEC/Intel 21143 and various workalikes
device fxp # Intel EtherExpress PRO/100B (82557, 82558)
#device pcn # AMD Am79C97x PCI 10/100 (precedence over lnc)
#device re # RealTek 8139C+/8169/8169S/8110S
#device rl # RealTek 8129/8139
#device sf # Adaptec AIC-6915 (``Starfire)
#device sis # Silicon Integrated Systems SiS 900/SiS 7016
#device sk # SysKonnect SK-984x and 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 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 ie # EtherExpress 8/16, 3C507, StarLAN 10 etc.
#device lnc # NE2100, NE32-VL Lance Ethernet cards
#device sn # SMCs 9000 series of ethernet chips
#device xe # Xircom pccard ethernet
# ISA devices that use the old ISA shims
#device le
# Wireless NIC cards
#device wlan # 802.11 support
#device an # Aironet 4500/4800 802.11 wireless NICs.
#device awi # BayStack 660 and others
#device wi # WaveLAN/Intersil/Symbol 802.11 wireless NICs.
#device wl # Older non 802.11 Wavelan wireless NIC.
# Pseudo devices - the number indicates how many units to allocate.
device random # Entropy device
device loop # Network loopback
device ether # Ethernet 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)
# The `bpf device enables the Berkeley Packet Filter.
# Be aware of the administrative consequences of enabling this!
device bpf # Berkeley packet filter
# USB support
device uhci # UHCI PCI->USB interface
device ohci # OHCI PCI->USB interface
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 Ethernet, requires mii
device aue # ADMtek USB ethernet
device axe # ASIX Electronics USB ethernet
device cue # CATC USB ethernet
device kue # Kawasaki LSI USB ethernet
# FireWire support
#device firewire # FireWire bus code
#device sbp # SCSI over FireWire (Requires scbus and da)
#device fwe # Ethernet over FireWire (non-standard!)
#
##############################################################################################
配置完成後，按ESC鍵，然後提示按"a"後再按"a"就能夠把配置檔案儲存。
三、編譯核心：
核心檔案配置好以後就能夠進行核心的編譯了，一般有兩種編譯的方式，我們採取傳統的編譯方式。
我們進入 /usr/src/sys/i386/conf 目錄：
# cd /usr/src/sys/i386/conf
執行config命令來產生核心原始碼。
# /usr/sbin/config GENERIC
切換到建立核心的目錄。
# cd ../compile/GENERIC
編譯核心
# make depend
# make
安裝新核心。
# make install
OK,到這裡，如果中間沒有出現任何錯誤的話，那麼我們的核心心就已經安裝成功了，reboot後就能夠使用我們的新編譯的核心了。如果出現了
錯誤，那麼請檢查你的步驟是否跟上面的步驟一致，同時要檢查你的核心配置檔案配置的是否正確，一般編譯不成功都是核心檔案配置的問題
，請仔細檢查。
四、新核心無法啟動：
如果你編譯的核心無法啟動，那麼可以使用以前的核心來啟動。一般編譯一次核心後，都會把把舊核心備份，一般/boot/kernel.old就是舊內
核的備份，出現問題就能夠使用久核心來啟動。
具體實現方法是：
你可以在系統啟動進行10計數的時候按Enter以外的任何鍵， 接著鍵入unload命令，再鍵入boot kernel.old，或者任何能正常啟動的核心名字
，然後就能夠正常啟動系統，進入系統後再重新進行核心的配置工作。
注意： 你不能僅依靠kernel.old，因為當你安裝一個新核心時， kernel.old會被上一次安裝的核心所覆蓋，所以你要麼自己手動備份一個能
正常啟動的核心，或者注意你的kernel.old是否能正常啟動的核心。
結束
好，到這裡，我們的編譯核心的工作就完成了，來然我們來看看我們的核心是否已經減小了：
# ls -l /boot/kernel/kernel
-r-xr-xr-x 1 root wheel 3090929 Sep 1 21:30 /boot/kernel/kernel
呵呵，明顯把原來的5940286變成了現在的3090929，雖然沒有變小一倍，但是也變小好多啦，以後系統又更快啦！
注意： 本文是在FreeBSD5.2.1的環境下進行的，不一定適合其他版本，特別是FreeBSD4.X版本，如果出現問題，請參考手冊。
附：
FreeBSD中文手冊: http://www.freebsd.org.cn/snap/doc/zh_CN.GB2312/books/handbook/index.html
核心配置參考: http://www.freebsd.org.cn/snap/doc/zh_CN.GB2312/bos/handbook/kernelconfig.html
我所用的FreeBSD是5.2.1版,現在是比較新的了,我一看我的核心檔案大小:
# ls -l /boot/kernel/kernel
-r-xr-xr-x 1 root wheel 5940286 Feb 24 2004 /boot/kernel.bak/kernel
看來不小呀，5M多，呵呵，我要把它編成 3M左右,呵呵，begin...
一、安裝核心原始碼
要編譯核心，首先必須保證核心的原始碼在，我們看看我們的系統有沒有安裝：
# ls /usr/src/sys
ls: /usr/src/sys: No such file or Directory
證明我們並沒有安裝核心原始碼，好，我們就安裝它。核心原始碼預設是安裝在了/usr/src/sys目錄下的，如果不存在該目錄，那麼證明你沒
有安裝原始碼。
我們先把我們的FreeBSD的安裝光碟放進光碟機，然後在FreeBSD下執行以root身份執行/stand/sysinstall， 選擇Configure，接著是
Distributions， 下來src， 最後sys,回車後能開始安裝了，一般只要幾分鐘就能安裝好，裝好了你就能檢視該資料夾：
# ls /usr/src/sys
Makefile ddb libkern netkey pci
alpha dev modules netnatm posix4
amd64 fs net netncp powerpc
arm geom net80211 netsmb rpc
boot gnu netatalk nfs security
cam i386 netatm nfs4clIEnt sparc64
coda i4b netgraph nfsclient sys
compat ia64 netinet nfsserver tools
conf isa netinet6 opencrypto ufs
contrib isofs netipsec pc98 vm
crypto kern netipx pccard
原始碼安裝好後，我們就可以開始我們的配置核心只旅啦。
二、配置核心檔案
其實我們編譯核心的關鍵就是配置核心檔案，核心配置檔案的目錄是在 /usr/src/sys/i386/conf 下，我們進入改目錄：
# cd /usr/src/sys/i386/conf
# ls
GENERIC GENERIC.hints NOTES PAE
Makefile OLDCARD gethints.awk
核心配置檔案就是GENERIC,我們要配置的就是它,配置包括要開啟那些硬體支援，IPv6支援，網絡卡等等。為了防止我們配置檔案配置後有問題，
我們先把它備份一下：
# cp GENERIC GENERIC.bak
然後我們就用任一編輯器開啟該檔案，可以使用vi，或者ee開啟，我為了方便，就使用ee來開啟：
# ee GENERIC
開啟後就有類似:
# GENERIC -- Generic kernel configuration file for FreeBSD/i386
#
# For more information on this file, please read the handbook section on
# Kernel Configuration Files:
的內容，前面有"#"代表該內容或者選項是註釋，那麼假如我們要去掉什麼選項，就可以在前面加上"#",當然你不需要的選項你也可刪除，但是
我推薦不需要的選項在前面加"#"。
關於配置檔案詳細的修改建議參考FreeBSD中文手冊關於核心配置選項的詳細說明：
http://www.freebsd.org.cn/snap/doc/zh_CN.GB2312/books/handbook/kernelconfig-config.HTML
我的配置檔案是這麼修改的，詳細我就不說明了,請檢視上面的配置檔案參考，應該適合大部分沒有ISA,SCSI,RAID等裝置的機器。
GENERIC核心配置檔案配置：
#########################################################################################
#
# GENERIC -- Generic kernel configuration file for FreeBSD/i386
#
# 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-config.html
#
# The handbook is also available locally in /usr/share/doc/handbook
# if youve 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/i386/conf/GENERIC,v 1.394.2.3 2004/01/26 19:42:11 nectar Exp $
Machine i386
#cpu I486_CPU
#cpu I586_CPU
cpu I686_CPU
ident GENERIC
#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_4BSD #4BSD scheduler
options INET #InterNETworking
#options INET6 #IPv6 communications protocols
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 MD_ROOT #MD is a potential root device
#options NFSCLIENT #Network Filesystem Client
#options NFSSERVER #Network Filesystem Server
#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 COMPAT_43 #Compatible with BSD 4.3 [KEEP THIS!]
options COMPAT_FREEBSD4 #Compatible with FreeBSD4
#options SCSI_DELAY=15000 #Delay (in ms) before probing SCSI
options KTRACE #ktrace(1) support
#options SYSVSHM #SYSV-style shared memory
options SYSVMSG #SYSV-style message queues
options SYSVSEM #SYSV-style semaphores
options _KPOSIX_PRIORITY_SCHEDULING #Posix P1003_1B real-time extensions
options KBD_INSTALL_CDEV # install a CDEV entry in /dev
options AHC_REG_PRETTY_PRINT # Print register bitfields in debug
# output. Adds ~128k to driver.
options AHD_REG_PRETTY_PRINT # Print register bitfields in debug
# output. Adds ~215k to driver.
options PFIL_HOOKS # pfil(9) framework
# Debugging for use in -current
#options DDB #Enable the kernel debugger
#options INVARIANTS #Enable calls of extra sanity checking
#options INVARIANT_SUPPORT #Extra sanity checks of internal structures, required by INVARIANTS
#options WITNESS #Enable checks to detect deadlocks and cycles
#options WITNESS_SKIPSPIN #Dont run witness on spinlocks for speed
# To make an SMP kernel, the next two are needed
#options SMP # Symmetric MultiProcessor Kernel
#device apic # I/O APIC
device isa
device eisa
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 ahb # EISA AHA1742 family
#device ahc # AHA2940 and onboard AIC7xxx devices
#device ahd # AHA39320/29320 and onboard AIC79xx devices
#device amd # AMD 53C974 (Tekram DC-390(T))
#device isp # Qlogic family
#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 aha # Adaptec 154x SCSI adapters
#device aic # Adaptec 15[012]x SCSI adapters, AIC-6[23]60.
#device bt # Buslogic/Mylex MultiMaster SCSI adapters
#device ncv # NCR 53C500
#device nsp # Workbit Ninja SCSI-3
#device stg # TMC 18C30/18C50
# SCSI peripherals
device scbus # SCSI bus (required for SCSI)
#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 asr # DPT SmartRAID V, VI and Adaptec SCSI RAID
#device ciss # Compaq Smart RAID 5*
#device dpt # DPT Smartcache III, IV - See NOTES for options
#device iir # Intel Integrated RAID
#device ips # IBM (Adaptec) ServeRAID
#device mly # Mylex AcceleRAID/eXtremeRAID
# RAID controllers
#device aac # Adaptec FSA RAID
#device aacp # SCSI passthrough for aac (requires CAM)
#device ida # Compaq Smart RAID
#device mlx # Mylex DAC960 family
#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 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
# Enable this for the pcvt (VT220 compatible) console driver
#device vt
#options XSERVER # support for X server on a vt console
#options FAT_CURSOR # start with block cursor
device agp # support several AGP chipsets
# Floating point support - do not disable.
device npx
# Power management support (see NOTES for more options)
#device apm
# Add suspend/resume support for the i8254.
#device pmtimer
# PCCARD (PCMCIA) support
# Pcmcia and cardbus bridge support
#device cbb # cardbus (yenta) bridge
#device pcic # ExCA ISA and PCI bridges
#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
# 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 youve 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 the sio and/or ppc drivers):
#device puc
# PCI Ethernet NICs.
#device de # DEC/Intel DC21x4x (``Tulip)
device em # Intel PRO/1000 adapter Gigabit Ethernet Card
#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
#device bfe # Broadcom BCM440x 10/100 ethernet
#device bge # Broadcom BCM570xx Gigabit Ethernet
#device dc # DEC/Intel 21143 and various workalikes
device fxp # Intel EtherExpress PRO/100B (82557, 82558)
#device pcn # AMD Am79C97x PCI 10/100 (precedence over lnc)
#device re # RealTek 8139C+/8169/8169S/8110S
#device rl # RealTek 8129/8139
#device sf # Adaptec AIC-6915 (``Starfire)
#device sis # Silicon Integrated Systems SiS 900/SiS 7016
#device sk # SysKonnect SK-984x and 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 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 ie # EtherExpress 8/16, 3C507, StarLAN 10 etc.
#device lnc # NE2100, NE32-VL Lance Ethernet cards
#device sn # SMCs 9000 series of ethernet chips
#device xe # Xircom pccard ethernet
# ISA devices that use the old ISA shims
#device le
# Wireless NIC cards
#device wlan # 802.11 support
#device an # Aironet 4500/4800 802.11 wireless NICs.
#device awi # BayStack 660 and others
#device wi # WaveLAN/Intersil/Symbol 802.11 wireless NICs.
#device wl # Older non 802.11 Wavelan wireless NIC.
# Pseudo devices - the number indicates how many units to allocate.
device random # Entropy device
device loop # Network loopback
device ether # Ethernet 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)
# The `bpf device enables the Berkeley Packet Filter.
# Be aware of the administrative consequences of enabling this!
device bpf # Berkeley packet filter
# USB support
device uhci # UHCI PCI->USB interface
device ohci # OHCI PCI->USB interface
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 Ethernet, requires mii
device aue # ADMtek USB ethernet
device axe # ASIX Electronics USB ethernet
device cue # CATC USB ethernet
device kue # Kawasaki LSI USB ethernet
# FireWire support
#device firewire # FireWire bus code
#device sbp # SCSI over FireWire (Requires scbus and da)
#device fwe # Ethernet over FireWire (non-standard!)
#
##############################################################################################
配置完成後，按ESC鍵，然後提示按"a"後再按"a"就能夠把配置檔案儲存。
三、編譯核心：
核心檔案配置好以後就能夠進行核心的編譯了，一般有兩種編譯的方式，我們採取傳統的編譯方式。
我們進入 /usr/src/sys/i386/conf 目錄：
# cd /usr/src/sys/i386/conf
執行config命令來產生核心原始碼。
# /usr/sbin/config GENERIC
切換到建立核心的目錄。
# cd ../compile/GENERIC
編譯核心
# make depend
# make
安裝新核心。
# make install
OK,到這裡，如果中間沒有出現任何錯誤的話，那麼我們的核心心就已經安裝成功了，reboot後就能夠使用我們的新編譯的核心了。如果出現了
錯誤，那麼請檢查你的步驟是否跟上面的步驟一致，同時要檢查你的核心配置檔案配置的是否正確，一般編譯不成功都是核心檔案配置的問題
，請仔細檢查。
四、新核心無法啟動：
如果你編譯的核心無法啟動，那麼可以使用以前的核心來啟動。一般編譯一次核心後，都會把把舊核心備份，一般/boot/kernel.old就是舊內
核的備份，出現問題就能夠使用久核心來啟動。
具體實現方法是：
你可以在系統啟動進行10計數的時候按Enter以外的任何鍵， 接著鍵入unload命令，再鍵入boot kernel.old，或者任何能正常啟動的核心名字
，然後就能夠正常啟動系統，進入系統後再重新進行核心的配置工作。
注意： 你不能僅依靠kernel.old，因為當你安裝一個新核心時， kernel.old會被上一次安裝的核心所覆蓋，所以你要麼自己手動備份一個能
正常啟動的核心，或者注意你的kernel.old是否能正常啟動的核心。
結束
好，到這裡，我們的編譯核心的工作就完成了，來然我們來看看我們的核心是否已經減小了：
# ls -l /boot/kernel/kernel
-r-xr-xr-x 1 root wheel 3090929 Sep 1 21:30 /boot/kernel/kernel
呵呵，明顯把原來的5940286變成了現在的3090929，雖然沒有變小一倍，但是也變小好多啦，以後系統又更快啦！
注意： 本文是在FreeBSD5.2.1的環境下進行的，不一定適合其他版本，特別是FreeBSD4.X版本，如果出現問題，請參考手冊。
附：
FreeBSD中文手冊: http://www.freebsd.org.cn/snap/doc/zh_CN.GB2312/books/handbook/index.html
核心配置參考: http://www.freebsd.org.cn/snap/doc/zh_CN.GB2312/bos/handbook/kernelconfig.html