Search     or:     and:
 LINUX 
 Language 
 Kernel 
 Package 
 Book 
 Test 
 OS 
 Forum 
 iakovlev.org 
 Kernels
 Boot 
 Memory 
 File system
 0.01
 1.0 
 2.0 
 2.4 
 2.6 
 3.x 
 4.x 
 Интервью 
 Kernel
=> HOW-TO 1
 Ptrace
 Kernel-Rebuild-HOWTO
 Runlevel
 Linux daemons
 FAQ
NEWS
Последние статьи :
  Rust 07.11   
  Go 25.12   
  EXT4 10.11   
  FS benchmark 15.09   
  Сетунь 23.07   
  Trees 25.06   
  Apache 03.02   
  SQL 30.07   
  JFS 10.06   
  B-trees 01.06   
 
TOP 20
 Trees...511 
 Go Web ...334 
 Python...166 
 2.0-> Linux IP Networking...139 
 Steve Pate 3...138 
 Стивенс 9...129 
 Rubni-Corbet -> Глав...128 
 Stein-MacEachern-> Час...119 
 Secure Programming for Li...119 
 Daniel Bovet 2...113 
 Mike Perry...113 
 Rubni-Corbet -> Глав...111 
 Advanced Bash Scripting G...111 
 Stevens-> Глава 4...110 
 Stewens -> IPC 7...108 
 Ethreal 4...105 
 Rubni-Corbet -> Глав...103 
 Stewens -> IPC 9...102 
 Stevens-> Глава 25...102 
 Stevens-> Глава 23...100 
 
  01.12.2017 : 2356398 посещений 

iakovlev.org

The Linux Kernel HOWTO

Al Dev (Alavoor Vasudevan)
        

v5.7, 04 May 2003

Это детализированное руководство по конфигурации,компиляции,апгрэйду ядра ,


Содержание
1. Введение
2. Первые шаги - компиляция
2.1. Подготовка
2.2. Апгрэйд
2.3. Для нетерпеливых
2.4. Построение нового ядра
2.5. Проблемы
2.6. Последние штрихи
3. Модули
3.1. Инсталляция модулей
3.2. Модули и ядро
3.3. Как проинсталлировать один модуль ?
4. Клонирование ядра
5. Вопросы и ответы
5.1. Что делает ядро?
5.2. Зачем нужен апгрэйд ядра?
5.3. Поддержка железа
5.4. Версии gcc и libc
5.5. Загружаемый модуль
5.6. Дисковое пространство
5.7. Время компиляции
6. Патчи
6.1. Добавление патча
6.2. Если что-то не получается
6.3. .orig файлы
6.4. Другие патчи
9. Документация
10. Информация
10.1. vmlinuz и vmlinux
10.2. Загрузочные файлы
10.3. Вывод сообщений
10.4. initrd.img
10.5. bzImage
10.6. module-info
10.7. config
10.8. grub
10.9. System.map
11. Процесс загрузки
11.1. Ссылки
12. О документе
12.1. PDF
12.2. Конвертация Linuxdoc -> Docbook
12.3. Конвертация в MS WinHelp
12.4. Другие форматы
13. Appendix A - создание initrd.img file
13.1. mkinitrd
13.2. Документация
13.3. Linuxman Book
14. Appendix B - lilo.conf
14.1. LILO
14.2. Проблемы с LILO
14.3. Примеры LILO
15. Appendix C - GRUB
15.1. GRUB
15.2. Tips On GRUB
15.3. Простой GRUB Conf File
16. Appendix D - Post Kernel Building
17. Appendix E - Стандартные ошибки
17.1. Компилится,но не запускается
17.2. Подвисает LILO
17.3. Не найден init
17.4. Ошибки компиляции
17.5. 'depmod' выдает "Unresolved symbol error messages"
17.6. Не загружается модуль - "Unresolved symbols" Error Messages
17.7. Крах при загрузке модуля
17.8. Загружаемые модули
17.9. Docs
17.10. make clean
17.11. Медленное ядро
17.12. Параллельный порт не работает с принтером
17.13. Ядро не компилируется
17.14. Новая версия ядра не загружается
17.15. вы забыли запустить LILO
17.16. `warning: bdflush not running'
17.17. Не определяется IDE/ATAPI CD-ROM
17.18. Маршрутизация
17.19. ``Not a compressed kernel Image file''
17.20. Проблемы с терминалом
17.21. Проблемы компиляции после апгрэйда ядра
17.22. Ограничения

1. Введение

Для компиляции ядра нужны следующие причины:

  • Вы занимаетесь разработкой ядра

  • Вы добавили новую железяку

  • Вас не устраивает вариант ядра , скомпилированный по умолчанию

  • Безопасность

  • Компиляция ядра - основа для понимания и чтения его кода .


2. Quick Steps - Kernel Compile

Эта секция написана Al Dev (alavoor[AT]yahoo.com) последняя версия документа - "http://www.milkywaygalaxy.freeservers.com" или здесь - angelfire , geocities .


2.1. Precautionary Preparations

Перед компиляцией ядра нужно сделать бэкап системы , хотя вообще-то это дело вкуса . Можно использовать для этого коммерческую тулзу BRS Backup-Recovery-Software

При компиляции старый конфиг нужно сохранить. Например , вот так :
 	bash# mv /usr/src/linux/.config  /usr/src/linux/.config.save
 	bash# cp /boot/config-2.4.18-19.8.0  /usr/src/linux/.config
         
Другой способ - скопировать конфиг из предыдущего каталога исходников ядра в новый каталог :
 	bash# ls -l /usr/src/lin*  # You can see that /usr/src/linux is a soft link
 	bash# cd /usr/src/linux 
 	bash# cp ../linux-old-tree/.config .  # Example cp ../linux-2.4.19/.config .
         

или вот так - "make oldconfig"


2.3. For the Impatient

  1. Распаковываем исходники из архива

  2. Сохраняем старый конфиг

  3. make clean; make mrproper

  4. make xconfig

  5. make dep

  6. Даем уникальное имя для нового ядра - подправляем /usr/src/linux/Makefile или меняем EXTRAVERSION

  7. nohup make bzImage

  8. 'make modules' и 'make modules_install'

  9. И можно идти на обед. Прийдя с обеда , можно посмотреть 'less nohup.out'.

  10. make install [num ] Физически при этом происходит следующее - use cp /usr/src/linux/arch/i386/boot/bzImage /boot/bzImage.myker

  11. Конфигурируем GRUB или LILO.

  12. Перезапуск

  13. Создаем загрузочный диск - bzdisk или mkbootdisk

  14. Создаем пакет - make rpm [num ]

  15. Подчистим - make clean


2.4. Building New Kernel - Explanation of Steps

Все нижеследующее проверялось на Redhat Linux Kernel 2.4.7-10, но с небольшими изминениями должно работать на предыдущих и будущих версиях.

  1. Распаковка исходников с сидирома :
     	bash$ su - root
     	bash# cd /mnt/cdrom/RedHat/RPMS 
     	bash# rpm -i kernel-headers*.rpm 
     	bash# rpm -i kernel-source*.rpm 
     	bash# rpm -i dev86*.rpm   
                   
    assembler 'as86' извлекается из dev86*.rpm на сиди или с bin86-mandrake , bin86-kondara ). Каталог /usr/src/linux должен быть линком .
     	bash# cd /usr/src
     bash# ls -l    # You should see that /usr/src/linux is soft link pointing to source
     lrwxrwxrwx    1 root     root           19 Jan 26 11:01 linux -> linux-2.4.18-19.8.0
     	drwxr-xr-x   17 root     root         4096 Jan 25 21:08 linux-2.4.18-14
     	drwxr-xr-x   17 root     root         4096 Mar 26 12:50 linux-2.4.18-19.8.0
     	drwxr-xr-x    7 root     root         4096 Jan 14 16:32 redhat
                   
    Если это не линк , то нужно переименовать каталог /usr/src/linux в каталог /usr/src/linux-2.4.yy и создать на него линк.

    Вообще-то компиляцию новой версии ядра можно делать где угодно.

  2. Сохраняем старый конфиг:
     	bash# mv /usr/src/linux/.config  /usr/src/linux/.config.save
     	bash# cp /boot/config-2.4.18-19.8.0  /usr/src/linux/.config
                   
    Или копируем конфиг :
     	bash# ls -l /usr/src/lin*  # You can see that /usr/src/linux is a soft link
     	bash# cd /usr/src/linux 
     	bash# cp ../linux-old-tree/.config .  # Example cp ../linux-2.4.19/.config .
                   
    или делаем "make oldconfig"

  3. Clean :
     	bash# cd /usr/src/linux 
     	bash# cp .config .config.save
     	bash# make clean
     	bash# make mrproper  # Must do this if want to start clean 
                                  # slate or if you face lot of problems
                   

  4. Конфигурация:

    • Стартуем X-windows
       	bash# man startx
       	bash# startx
       	bash# cd /usr/src/linux 
       	bash# make xconfig 
                           

    • Если не удалось запустить виндовую конфигурацию ядра - пробуем терминальную
       		bash# export TERM=xterm
       		bash# make menuconfig
       If you find scrambled display, then use different terminal emulators like vt100,
       	vt102, vt220 or ansi. The display will be scrambled and will have garbage 
       	characters in cases where you use telnet to login to remote linux. In such 
       	cases you should use the terminal emulators like vt100, vt220. 
       	For example:
       		bash# export TERM=vt220
       		bash# export TERM=ansi
       	At a lower level of VT, use: 
       		bash# export TERM=vt100
       		bash# make menuconfig
       	If the menuconfig command fails then try -
       		bash# make config
                           

    Утилиты "make xconfig" или"make menuconfig" запускают интерактивный дружественный интерфейс . Команда "make config" запускает более детерминированный command-line консольный интерфейс.

    • ОЧЕНЬ ВАЖНО !!! : Выбираем соответствующий тип CPU - Pentium 3, AMD K6, Cyrix, Pentium 4, Intel 386, DEC Alpha, PowerPC - в противном случае будут либо ошибки при компиляции , либо новое ядро вообще не будет загружаться !!

    • Выбираем SMP support - один CPU или несколько

    • Выбираем Filesystems

    • Выбираем поддержку Loadable kernel modules !

    Сохраняем и выходим из "make xconfig". Изменения сохранены в /usr/src/linux/.config

  5. Dep :
     	bash# make dep
                   

  6. Теперь дадим уникальное имя новому ядру - пропишем это в Makefile:
     	bash# cd /usr/src/linux
     	bash# vi Makefile
                   
    Пусть системная переменная EXTRAVERSION = -19.8.0_Blah_Blah_Blah . Меяем ее на что-то типа EXTRAVERSION = -19.8.0MyKernel.26Jan2003

  7. make: Сначала читаем :
     	bash# gvim -R   /usr/src/linux/arch/i386/config.in 
     	bash# man less 
     	bash# less   /usr/src/linux/arch/i386/config.in 
     	Type 'h' for help and to navigate press i, j, k, l, h or arrow, page up/down keys. 
                   
    Теперь запускаем make -
     		bash# cd /usr/src/linux
     		bash# man nohup
     		bash# nohup make bzImage &  
     		bash# man tail
     		bash# tail -f nohup.out     (.... to monitor the progress) 
     	This will put the kernel in /usr/src/linux/arch/i386/boot/bzImage 
                     

  8. Загружаемые модули: они находятся в /lib/modules.
     	# Bring up a new Xterm shell window and ...
     	bash# cd /usr/src/linux
     	# Redirect outputs such that you do not overwrite the nohup.out 
             # which is still running...
     	bash# nohup make modules 1> modules.out 2> modules.err  &
     	bash# make modules_install   
                   
    Копирует модули в /lib/modules .

  9. Идем обедать . Возвращаемся с обеда и смотрим лог .
     	bash# cd /usr/src/linux
     	bash# less nohup.out
     	bash# less modules.err
     	bash# less modules.out
     	If no errors then do:
     	bash# make modules_install  
                   

  10. bzImage: Копируем образ в каталог /boot , а также конфиг .
     	bash# cp /usr/src/linux/arch/i386/boot/bzImage     /boot/bzImage.myker.26mar2001
     	# You MUST copy the config file to reflect the corresponding kernel image, 
     	# for documentation purpose.
     	bash# cp /usr/src/linux/.config /boot/config-<your_kernelversion_date>
     	# Example: cp /usr/src/linux/.config /boot/config-2.4.18-19.8.0-26mar2001
                   

  11. Конфигурация GRUB или LILO : Под Redhat Linux есть 2 загрузчика - GRUB и LILO. GRUB: GRUB поновее и покруче , чем LILO . Загрузчик позволяет иметь на одном компе несколько разных осей.

  12. Делаем перезапуск и в лило жмем на клавишу таб , после чего набираем 'myker' Если все грузится , значит новое ядро удалось , в противном случае будет загружен старый образ.

  13. Создаем загрузочный флоппи :
     	bash# cd /usr/src/linux
     	bash# make bzdisk
     	See also mkbootdisk -
     	bash# rpm -i mkbootdisk*.rpm
     	bash# man mkbootdisk
                   

  14. Закатаем новый образ в RPM
     	make rpm   # To build rpm packages
                     

  15. Clean: опционально .


2.5. Troubleshooting

Проблемы? Смотри Section 17 .


2.6. Post Kernel Building

Смотри Section 16 .


3. Loadable Modules

Загружаемые модули - это код , который напрямую не привязан к ядру . Их можно произвольным образом компилировать и добавлять к ядру . Многие драйвера устройств , такие как PCMCIA , являются загружаемыми модулями.

Смотри "http://www.tldp.org/HOWTO/Module-HOWTO" .

Информацию по загружаемым модулям можно взять в мане
 	bash# rpm -i /mnt/cdrom/Redhat/RPMS/modutils*.rpm
 	bash# man lsmod
 	bash# man insmod
 	bash# man rmmod
 	bash# man depmod
 	bash# man modprobe
       
Например для загрузки модуля /lib/modules/2.4.2-2/kernel/drivers/block/loop.o , нужно выполнить :
 	bash# man insmod
 	bash# modprobe loop
 	bash# insmod loop
 	bash# lsmod 
       
При этом путь к модулю ищется в /etc/modules.conf.


3.1. Installing the module utilities

Можно инсталлировать модульные утилиты так :
 	bash# rpm -i /mnt/cdrom/Redhat/RPMS/modutils*.rpm
         

insmod добавляет модуль к ядру , которое уже запущено. Модули обычно имеют расширение .o . Для того , чтобы посмотреть , какие модули использует текущее ядро надо набрать lsmod . Вывод будет примерно такой : blah# lsmod Module: #pages: Used by: drv_hello 1 ` . Для удаления модулей используйте ` rmmod drv_hello '. Обратите внимание , что rmmod требует имя модуля, а не имя файла; имя модуля можно получить с помощью lsmod '.


3.2. Modules distributed with the kernel

Начиная с версии 2.0.30, большинство модулей загружаемые . Порядок компиляции следующий : откомпилировав ядро , презапуститесь через него . Затем : cd to /usr/src/linux и выполняем ` make modules '. Эта команда откомпилирует все модули , не определенные в конфигурации и разместит линки на них в /usr/src/linux/modules . Затем выполняем ` make modules_install ', которая установит их в /lib/modules/x.y.z , где x.y.z есть номер релиза.


3.3. Howto Install Just A Single Module ?

Предположим , что вы захотели изменить код в одном из модулей и хотите перекомпилировать только его.

Можно откомпилировать единственный модуль и инсталлировать его. Для этого в Makefile можно использовать SUBDIRS для добавления только тех директорий, которые вас интересуют.

Например для модуля fs/autofs :
 	cd /usr/src/linux
 	cp Makefile Makefile.my
 	vi Makefile.my  
 	# And comment out the line having 'SUBDIRS' and add the 
 	# directory you are interested, for example like fs/autofs as below :
 		#SUBDIRS	=kernel drivers mm fs net ipc lib abi crypto
 		SUBDIRS		=fs/autofs
 	# Save the file Makefile.my and give -
 	make -f Makefile.my modules
 	# This will create module autofs.o
 	# Now, copy the module object file to destination /lib/modules
 	make -f Makefile.my modules_install
 	# And this will do 'cp autofs.o /lib/modules/2.4.18-19.8.0/kernel/fs/autofs'
         

О Makefile и make можно почитать здесь :

Для Makefile , который лежит в подкаталоге модулей , есть строка
 	modules: $(patsubst %, _mod_%, $(SUBDIRS))
         

Функция patsubst имеет синтаксис $(patsubst pattern,replacement,text). Она использует символ процент ([percnt]) как строку соответствующую шаблону .

В этот makefile входят шелл-функции , которые имеют синтаксис $(shell command).


4. Cloning of Linux Kernels

Для переноса нового образа на другие машины можно использовать редхатовские пакеты. или дебиановские (DEB) пакеты или просто архивы tar.gz .

  1. Пакет строится командой rpmbuild -ba kernel*.spec

  2. Проверьте , что пакет имеет образ в виде файла /boot/initrd-2.x.x-y.img .


5. Important questions and their answers

5.1. What does the kernel do, anyway?

Ядро управляет памятью всех процессов и обеспечивает портабельный интерфейс для общения программ с железом.


5.2. Why would I want to upgrade my kernel?

Новые версии ядра могут общаться с большим количеством железа,лучше управляют памятью, они просто быстрее старых.


5.3. What kind of hardware do the newer kernels support?

Смотрите Hardware-HOWTO . Можно посмотреть в ` config.in ' или просто набрать ` make config '. Будет показан полный список оборудования , поддерживаемого ядром.


5.4. What version of gcc and libc do I need?

Версию gcc можно посмотреть в README .


5.5. What's a loadable module?

Смотрите Section 3 .


5.6. How much disk space do I need?

Это зависит от конфигурации . Исходники 2.2.9 весят 14 метров.


5.7. How long does it take?

На AMD K6-2/300 компиляция 2.2.x занимает около 4 минут . На 486s, и 386s, это может занимать часы ...

Можно компилировать на быстрых машинах и потом переносить на медленные.


6. Patching the kernel

6.1. Applying a patch

Незначительные изменения ядра называются патчами. Например , если у вас Linux v1.1.45, и у вас есть patch46.gz ' , это значит что вы можете проапгрэйдить версию до 1.1.46 с помощью этого патча. Вначале можно сделать бэкап исходников : ` make clean ' и затем ` cd /usr/src; tar zcvf old-tree.tar.gz linux ' будет создан архив.

Итак , предположим , что у нас имеется ` patch46.gz ' в каталоге /usr/src . Делаем cd /usr/src и затем ` zcat patch46.gz [verbar] patch -p0 ' (or ` patch -p0 [lt ] patch46 ' . После чего набираем -s вместе с командой patch , которая говорит patch вывести только ошибки . Затем идем в каталог /usr/src/linux и смотрим на файл .rej

Если все нормально , делаем ` make clean ', ` config ', и ` dep ' .

patch -s ничего не выводит , кроме ошибок .


6.2. If something goes wrong

Проблемы при патчах возникают после того , как изменяется config.in ' . Но есть файл config.in.rej , с помощью которого можно посмотреть разницу. Изменения маркируются ` + ' и ` - ' в начале линии. Изменив в config.in y ' на ` n ' и ` n ' на ` y ' , можно добиться желаемого результата.


6.3. Getting rid of the .orig files

В результате патчей создаются файлы .orig . Команда find . -name '*.orig' -exec rm -f {} ';' удаляет их .


6.4. Other patches

Патчи от нестандартных дистрибутивов могут привести к проблемам .


9. Linux Kernel Textbooks and Documents

Книги из серии "The Linux Kernel"

Refer also to other relevant HOWTOs at:


10. Kernel Files Information

Краткий экскурс в Linux Kernel System.


10.1. vmlinuz and vmlinux

vmlinuz - исполняемый файл ядра . Находится в /boot/vmlinuz. Часто это может быть линком на что-то типа /boot/vmlinuz-2.4.18-19.8.0

vmlinux - это несжатое ядро, vmlinuz - сжатое , создаваемое при запуске .

Еще есть bzImage, который хранится в arch/i386/boot.


10.2. Bootloader Files

Файлы с раширением .b - "bootloader" файлы. Необходимы для загрузки ядра в память.
 	ls -l /boot/*.b
 	-rw-r--r--    1 root     root         5824 Sep  5  2002 /boot/boot.b
 	-rw-r--r--    1 root     root          612 Sep  5  2002 /boot/chain.b
 	-rw-r--r--    1 root     root          640 Sep  5  2002 /boot/os2_d.b
         


10.3. Message File

Файлы 'message' включают сообщения , которые выводятся на экран.
 	ls -l /boot/message*
 	-rw-r--r--    1 root     root        23108 Sep  6  2002 /boot/message
 	-rw-r--r--    1 root     root        21282 Sep  6  2002 /boot/message.ja
         


10.4. initrd.img

Смотри Section 13 .


10.5. bzImage

bzImage - сжатый образ ядра , созданный командой 'make bzImage' .


10.6. module-info

This file 'module-info' is created by anaconda/utils/modlist (specific to Redhat Linux Anaconda installer). Other Linux distributions may be having equivalent command. Refer to your Linux distributor's manual pages.

See this script and search for "module-info" updmodules .

Below is a cut from this script:
 	#!/bin/bash
 	# updmodules.sh
 		MODLIST=$PWD/../anaconda/utils/modlist
 	-- snip cut 
 	blah blah blah 
 	-- snip cut 
 	    # create the module-info file
 	    $MODLIST --modinfo-file $MODINFO --ignore-missing --modinfo \
 			$(ls *.o | sed 's/\.o$//') > ../modinfo
         

The program anaconda/utils/modlist is located in anaconda-runtime*.rpm on the Redhat CDROM
 	cd /mnt/cdrom/RedHat/RPMS
 	rpm -i anaconda-8.0-4.i386.rpm
 	rpm -i anaconda-runtime-8.0-4.i386.rpm
 	ls -l /usr/lib/anaconda-runtime/modlist
         
Get the source code for anaconda/utils/modlist.c from anaconda*.src.rpm at "http://www.rpmfind.net/linux/rpm2html/search.php?query=anaconda" Read online at modlist.c . .

The file 'module-info' is generated during the compile. It is an information file that is at least used during filing proper kernel OOPS reports. It is a list of the module entry points. It may also be used by depmod in building the tables that are used by insmod and its kith and kin. This includes dependancy information for other modules needed to be loaded before any other given module, etc. "Don't remove it."

Some points about module-info:

  • Is provided by the kernel rpms (built by anaconda-runtime*.rpm)

  • Is a link to module-info-[lcub ]kernel-version[rcub ]

  • Contains information about all available modules (at least those included in the default kernel config.)

  • Important to anaconda - in anaconda/utils/modlist command.

  • Might be used by kudzu to determine default parameters for modules when it creates entries in /etc/modules.conf. If you move module-info out of the way, shut down, install a new network card, and re-boot then kudzu would complain loudly. Look at the kudzu source code.


10.7. config

Everytime you compile and install the kernel image in /boot, you should also copy the corresponding config file to /boot area, for documentation and future reference. Do NOT touch or edit these files!!
 	ls -l /boot/config-*
 	-rw-r--r--    1 root     root        42111 Sep  4  2002 /boot/config-2.4.18-14
 	-rw-r--r--    1 root     root        42328 Jan 26 01:29 /boot/config-2.4.18-19.8.0
 	-rw-r--r--    1 root     root        51426 Jan 25 22:21 /boot/config-2.4.18-19.8.0BOOT
 -rw-r--r--    1 root     root        52328 Jan 28 03:22 /boot/config-2.4.18-19.8.0-26mar2003
         


10.8. grub

If you are using GRUB, then there will be 'grub' directory.
 	ls /boot/grub
 	device.map     ffs_stage1_5  menu.lst        reiserfs_stage1_5  stage2
 	e2fs_stage1_5  grub.conf     minix_stage1_5  splash.xpm.gz      vstafs_stage1_5
 	fat_stage1_5   jfs_stage1_5  stage1          xfs_stage1_5
         
See also Section 15 file.


10.9. System.map

System.map is a "phone directory" list of function in a particular build of a kernel. It is typically a symlink to the System.map of the currently running kernel. If you use the wrong (or no) System.map, debugging crashes is harder, but has no other effects. Without System.map, you may face minor annoyance messages.

Do NOT touch the System.map files.
 	ls -ld /boot/System.map*
 lrwxrwxrwx 1 root root 30 Jan 26 19:26 /boot/System.map -> System.map-2.4.18-19.8.0custom
 -rw-r--r--    1 root     root       501166 Sep  4  2002 /boot/System.map-2.4.18-14
 -rw-r--r--    1 root     root       510786 Jan 26 01:29 /boot/System.map-2.4.18-19.8.0
 -rw-r--r-- 1 root     root    331213 Jan 25 22:21 /boot/System.map-2.4.18-19.8.0BOOT
 -rw-r--r-- 1 root     root    503246 Jan 26 19:26 /boot/System.map-2.4.18-19.8.0custom
         

How The Kernel Symbol Table Is Created ? System.map is produced by 'nm vmlinux' and irrelevant or uninteresting symbols are grepped out, When you compile the kernel, this file 'System.map' is created at /usr/src/linux/System.map. Something like below:
 	nm /boot/vmlinux-2.4.18-19.8.0 > System.map
 	# Below is the line from /usr/src/linux/Makefile 
 nm vmlinux | grep -v '\(compiled\)\|\(\.o$$\)\|\( [aUw] \)\|\(\.\.ng$$\)\|\(LASH[RL]DI\)' | 
         sort > System.map
 	cp /usr/src/linux/System.map /boot/System.map-2.4.18-14   # For v2.4.18
         

From "http://www.dirac.org/linux/systemmap.html"


10.9.1. System.map

There seems to be a dearth of information about the System.map file. It's really nothing mysterious, and in the scheme of things, it's really not that important. But a lack of documentation makes it shady. It's like an earlobe; we all have one, but nobody really knows why. This is a little web page I cooked up that explains the why.

Note, I'm not out to be 100[percnt] correct. For instance, it's possible for a system to not have /proc filesystem support, but most systems do. I'm going to assume you "go with the flow" and have a fairly typical system.

Some of the stuff on oopses comes from Alessandro Rubini's "Linux Device Drivers" which is where I learned most of what I know about kernel programming.


10.9.2. What Are Symbols?

In the context of programming, a symbol is the building block of a program: it is a variable name or a function name. It should be of no surprise that the kernel has symbols, just like the programs you write. The difference is, of course, that the kernel is a very complicated piece of coding and has many, many global symbols.


10.9.3. What Is The Kernel Symbol Table?

The kernel doesn't use symbol names. It's much happier knowing a variable or function name by the variable or function's address. Rather than using size_t BytesRead, the kernel prefers to refer to this variable as (for example) c0343f20.

Humans, on the other hand, do not appreciate names like c0343f20. We prefer to use something like size_t BytesRead. Normally, this doesn't present much of a problem. The kernel is mainly written in C, so the compiler/linker allows us to use symbol names when we code and allows the kernel to use addresses when it runs. Everyone is happy.

There are situations, however, where we need to know the address of a symbol (or the symbol for an address). This is done by a symbol table, and is very similar to how gdb can give you the function name from a address (or an address from a function name). A symbol table is a listing of all symbols along with their address. Here is an example of a symbol table:

 	   c03441a0 B dmi_broken
 	   c03441a4 B is_sony_vaio_laptop
 	   c03441c0 b dmi_ident
 	   c0344200 b pci_bios_present
 	   c0344204 b pirq_table
 	   c0344208 b pirq_router
 	   c034420c b pirq_router_dev
 	   c0344220 b ascii_buffer
 	   c0344224 b ascii_buf_bytes
           

You can see that the variable named dmi_broken is at the kernel address c03441a0.


10.9.4. What Is The System.map File?

There are 2 files that are used as a symbol table:

  1. /proc/ksyms

  2. System.map

There. You now know what the System.map file is.

Every time you compile a new kernel, the addresses of various symbol names are bound to change.

/proc/ksyms is a "proc file" and is created on the fly when a kernel boots up. Actually, it's not really a file; it's simply a representation of kernel data which is given the illusion of being a disk file. If you don't believe me, try finding the filesize of /proc/ksyms. Therefore, it will always be correct for the kernel that is currently running..

However, System.map is an actual file on your filesystem. When you compile a new kernel, your old System.map has wrong symbol information. A new System.map is generated with each kernel compile and you need to replace the old copy with your new copy.


10.9.5. What Is An Oops?

What is the most common bug in your homebrewed programs? The segfault. Good ol' signal 11.

What is the most common bug in the Linux kernel? The segfault. Except here, the notion of a segfault is much more complicated and can be, as you can imagine, much more serious. When the kernel dereferences an invalid pointer, it's not called a segfault -- it's called an "oops". An oops indicates a kernel bug and should always be reported and fixed.

Note that an oops is not the same thing as a segfault. Your program cannot recover from a segfault. The kernel doesn't necessarily have to be in an unstable state when an oops occurs. The Linux kernel is very robust; the oops may just kill the current process and leave the rest of the kernel in a good, solid state.

An oops is not a kernel panic. In a panic, the kernel cannot continue; the system grinds to a halt and must be restarted. An oops may cause a panic if a vital part of the system is destroyed. An oops in a device driver, for example, will almost never cause a panic.

When an oops occurs, the system will print out information that is relevent to debugging the problem, like the contents of all the CPU registers, and the location of page descriptor tables. In particular, the contents of the EIP (instruction pointer) is printed. Like this:
 	   EIP: 0010:[<00000000>]
 	   Call Trace: [<c010b860>]
           


10.9.6. What Does An Oops Have To Do With System.map?

You can agree that the information given in EIP and Call Trace is not very informative. But more importantly, it's really not informative to a kernel developer either. Since a symbol doesn't have a fixed address, c010b860 can point anywhere.

To help us use this cryptic oops output, Linux uses a daemon called klogd, the kernel logging daemon. klogd intercepts kernel oopses and logs them with syslogd, changing some of the useless information like c010b860 with information that humans can use. In other words, klogd is a kernel message logger which can perform name-address resolution. Once klogd tranforms the kernel message, it uses whatever logger is in place to log system wide messages, usually syslogd.

To perform name-address resolution, klogd uses System.map. Now you know what an oops has to do with System.map.

Fine print: There are actually two types of address resolution are performed by klogd.

  • Static translation, which uses the System.map file.

  • Dynamic translation which is used with loadable modules, doesn't use

System.map and is therefore not relevant to this discussion, but I'll describe it briefly anyhow.

Klogd Dynamic Translation

Suppose you load a kernel module which generates an oops. An oops message is generated, and klogd intercepts it. It is found that the oops occured at d00cf810. Since this address belongs to a dynamically loaded module, it has no entry in the System.map file. klogd will search for it, find nothing, and conclude that a loadable module must have generated the oops. klogd then queries the kernel for symbols that were exported by loadable modules. Even if the module author didn't export his symbols, at the very least, klogd will know what module generated the oops, which is better than knowing nothing about the oops at all.

There's other software that uses System.map, and I'll get into that shortly.


10.9.7. Where Should System.map Be Located?

System.map should be located wherever the software that uses it looks for it. That being said, let me talk about where klogd looks for it. Upon bootup, if klogd isn't given the location of System.map as an argument, it will look for System.map in 3 places, in the following order:

  1. /boot/System.map

  2. /System.map

  3. /usr/src/linux/System.map

System.map also has versioning information, and klogd intelligently searches for the correct map file. For instance, suppose you're running kernel 2.4.18 and the associated map file is /boot/System.map. You now compile a new kernel 2.5.1 in the tree /usr/src/linux. During the compiling process, the file /usr/src/linux/System.map is created. When you boot your new kernel, klogd will first look at /boot/System.map, determine it's not the correct map file for the booting kernel, then look at /usr/src/linux/System.map, determine that it is the correct map file for the booting kernel and start reading the symbols.

A few nota bene's:

  • Somewhere during the 2.5.x series, the Linux kernel started to untar into linux-version, rather than just linux (show of hands -- how many people have been waiting for this to happen?). I don't know if klogd has been modified to search in /usr/src/linux-version/System.map yet. TODO: Look at the klogd srouce. If someone beats me to it, please email me and let me know if klogd has been modified to look in the new directory name for the linux source code.

  • The man page doesn't tell the whole the story. Look at this:

 	   # strace -f /sbin/klogd | grep 'System.map'
 	   31208 open("/boot/System.map-2.4.18", O_RDONLY|O_LARGEFILE) = 2
           

Apparently, not only does klogd look for the correct version of the map in the 3 klogd search directories, but klogd also knows to look for the name "System.map" followed by "-kernelversion", like System.map-2.4.18. This is undocumented feature of klogd.

A few drivers will need System.map to resolve symbols (since they're linked against the kernel headers instead of, say, glibc). They will not work correctly without the System.map created for the particular kernel you're currently running. This is NOT the same thing as a module not loading because of a kernel version mismatch. That has to do with the kernel version, not the kernel symbol table which changes between kernels of the same version!


10.9.8. What else uses the System.map

Don't think that System.map is only useful for kernel oopses. Although the kernel itself doesn't really use System.map, other programs such as klogd, lsof,

 	   satan# strace lsof 2>&1 1> /dev/null | grep System
 	   readlink("/proc/22711/fd/4", "/boot/System.map-2.4.18", 4095) = 23
           

and ps :

 	   satan# strace ps 2>&1 1> /dev/null | grep System
 	   open("/boot/System.map-2.4.18", O_RDONLY|O_NONBLOCK|O_NOCTTY) = 6
           

and many other pieces of software like dosemu require a correct System.map.


10.9.9. What Happens If I Don't Have A Healthy System.map?

Suppose you have multiple kernels on the same machine. You need a separate System.map files for each kernel! If boot a kernel that doesn't have a System.map file, you'll periodically see a message like: System.map does not match actual kernel Not a fatal error, but can be annoying to see everytime you do a ps ax. Some software, like dosemu, may not work correctly (although I don't know of anything off the top of my head). Lastly, your klogd or ksymoops output will not be reliable in case of a kernel oops.


10.9.10. How Do I Remedy The Above Situation?

The solution is to keep all your System.map files in /boot and rename them with the kernel version. Suppose you have multiple kernels like:

  • /boot/vmlinuz-2.2.14

  • /boot/vmlinuz-2.2.13

Then just rename your map files according to the kernel version and put them in /boot, like:
 	   /boot/System.map-2.2.14
 	   /boot/System.map-2.2.13
           

Now what if you have two copies of the same kernel? Like:

  • /boot/vmlinuz-2.2.14

  • /boot/vmlinuz-2.2.14.nosound

The best answer would be if all software looked for the following files:
 	   /boot/System.map-2.2.14
 	   /boot/System.map-2.2.14.nosound
           

You can also use symlinks:
 	   System.map-2.2.14
 	   System.map-2.2.14.sound
 ln -s System.map-2.2.14.sound System.map # Here System.map -> System.map-2.2.14.sound
           


11. Advanced Topics - Linux Boot Process

This section may not be interesting for 'average Joe home PC user' but will be more directed towards someone with computer science background.

The chain of events at boot are: CPU-> VGA-> Power-On-Self-Test-> SCSI-> Boot Manager-> Lilo boot loader-> kernel-> init-> bash. The firmware and software programs output various messages as the computer and Linux come to life.

A guided tour of a Linux Boot process:

  1. The Motherboard BIOS Triggers the Video Display Card BIOS Initialization

  2. Motherboard BIOS Initializes Itself

  3. SCSI Controller BIOS Initializes

  4. Hardware Summary: The motherboard BIOS then displays the following summary of its hardware inventory. And runs its Virus checking code that looks for changed boot sectors.

  5. BootManager Menu : The Master Boot Record (MBR) on the first hard disk is read, by DOS tradition, into address 0x00007c00, and the processor starts executing instructions there. This MBR boot code loads the first sector of code on the active DOS partition.

  6. Lilo is started: If the Linux selection is chosen and if Linux has been installed with Lilo, Lilo is loaded into address 0x00007c00. Lilo prints LILO with its progress revealed by individually printing the letters. The first "L" is printed after Lilo moves itself to a better location at 0x0009A000. The "I" is printed just before it starts its secondary boot loader code. Lilo's secondary boot loader prints the next "L", loads descriptors pointing to parts of the kernel, and then prints the final "O". The descriptors are placed at 0x0009d200. The boot message and a prompt line, if specified, are printed. The pressing "Tab" at the prompt, allows the user to specify a system and to provide command-line specifications to the Linux Kernel, its drivers, and the "init" program. Also, environment variables may be defined at this point.
     The following line is from /boot/message:
     >
     >
     >
      Press  to list available boot image labels.
     The following line is the prompt from /sbin/lilo:
     boot:
     Note: If Lilo is not used, then the boot code built into the head 
           of the Linux kernel, linux/arch/i386/boot/bootsect.S 
     	  prints "Loading" and continues.
     Lilo displays the following as it loads the kernel code. It gets the 
     text "Linux-2.2.12" from the "label=..." specification in lilo.conf.
     Loading linux-2.2.12..........
     		  	

  7. The kernel code in /linux/arch/i386/boot/setup.S arranges the transition from the processor running in real mode (DOS mode) to protected mode (full 32-bit mode). Blocks of code named Trampoline.S and Trampoline32.S help with the transition. Small kernel images (zImage) are decompressed and loaded at 0x00010000. Large kernel images (bzImage) are loaded instead at 0x00100000. This code sets up the registers, decompresses the compressed kernel (which has linux/arch/i386/head.S at its start), printing the following 2 lines from linux/arch/i386/boot/compressed/misc.c Uncompressing Linux... Ok. Booting the kernel. The i386-specific setup.S code has now completed its job and it jumps to 0x00010000 (or 0x00100000) to start the generic Linux kernel code.

    • Processor, Console, and Memory Initialization : This runs linux/arch/i386/head.S which in turn jumps to start_kernel(void) in linux/init/main.c where the interrupts are redefined. linux/kernel/module.c then loads the drivers for the console and pci bus. From this point on the kernel messages are also saved in memory and available using /bin/dmesg. They are then usually transferred to /var/log/message for a permanent record.

    • PCI Bus Initialization : mpci_init() in linux/init/main.c causes the following lines from linux/arch/i386/kernel/bios32.c to be printed:

    • Network Initialization: socket_init() in linux/init/main.c causes the following network initializations:
       linux/net/socket.c prints:
       Linux NET4.0 for Linux 2.2
       Based upon Swansea University Computer Society NET3.039
       linux/net/unix/af_unix.c prints:
       NET4: Unix domain sockets 1.0 for Linux NET4.0.
       linux/net/ipv4/af_inet.c prints:
       NET4: Linux TCP/IP 1.0 for NET4.0
       IP Protocols: ICMP, UDP, TCP
       linux/net/ipv4/ip_gre.c prints:
       GRE over IPv4 tunneling driver
       linux/net/core/dev.c prints:
       early initialization of device gre0 is deferred
       linux/net/core/rtnetlink.c prints:
       Initializing RT netlink socket
       					

    • The Kernel Idle Thread (Process 0) is Started : At this point a kernel thread is started running init() which is one of the routines defined in linux/init/main.c. This init() must not be confused with the program /sbin/init that will be run after the Linux kernel is up and running. mkswapd_setup() in linux/init/main.c causes the following line from linux/mm/vmscan.c to be printed: Starting kswapd v 1.5

    • Device Driver Initialization : The kernel routine linux/arch/i386/kernel/setup.c then initializes devices and file systems (built into the kernel??). It produces the following lines and then forks to run /sbin/init:

      • Generic Parallel Port Initialization : The parallel port initialization routine linux/drivers/misc/parport_pc.c prints the following:

      • Character Device Initializations : The following 3 lines are from linux/drivers/char/serial.c:

      • Block Device Initializations : linux/drivers/block/rd.c prints: RAM disk driver initialized: 16 RAM disks of 8192K size linux/drivers/block/loop.c prints: loop: registered device at major 7 linux/drivers/block/floppy.c prints: Floppy drive(s): fd0 is 1.44M, fd1 is 1.44M FDC 0 is a post-1991 82077

      • SCSI Bus Initialization: The following lines are from aic7xxx.c, scsi.c, sg.c, sd.c or sr.c in the subdirectory linux/drivers/scsi:

    • Initialization of Kernel Support for Point-to-Point Protocol : The following initialization is done by linux/drivers/net/ppp.c.

    • Examination of Fixed Disk Arrangement : The following lines are from linux/drivers/block/genhd.c:

  8. Init Program (Process 1) Startup : The program /sbin/init is started by the "idle" process (Process 0) code in linux/init/main.c and becomes process 1. /sbin/init then completes the initialization by running scripts and forking additional processes as specified in /etc/inittab. It starts by printing: INIT: version 2.76 booting and reads /etc/inittab.

  9. The Bash Shell is Started : The bash shell, /bin/bash is then started up. Bash initialization begins by executing script in /etc/profile which set the system-wide environment variables:


12. Other Formats of this Document

This section is written by Al Dev (at site "http://www.milkywaygalaxy.freeservers.com" mirrors at angelfire , geocities , virtualave , Fortunecity , Freewebsites , Tripod , 101xs , 50megs )

This document is published in 14 different formats namely - DVI, Postscript, Latex, Adobe Acrobat PDF, LyX, GNU-info, HTML, RTF(Rich Text Format), Plain-text, Unix man pages, single HTML file, SGML (Linuxdoc format), SGML (Docbook format), MS WinHelp format.

This howto document is located at -

You can also find this document at the following mirrors sites -

The document is written using a tool called "SGML-Tools" which can be got from - "http://www.sgmltools.org" Compiling the source you will get the following commands like

  • sgml2html xxxxhowto.sgml (to generate html file)

  • sgml2html -split 0 xxxxhowto.sgml (to generate a single page html file)

  • sgml2rtf xxxxhowto.sgml (to generate RTF file)

  • sgml2latex xxxxhowto.sgml (to generate latex file)


12.1. Acrobat PDF format

PDF file can be generated from postscript file using either acrobat distill or Ghostscript . And postscript file is generated from DVI which in turn is generated from LaTex file. You can download distill software from "http://www.adobe.com" . Given below is a sample session:
 	bash$ man sgml2latex
 	bash$ sgml2latex filename.sgml
 	bash$ man dvips
 	bash$ dvips -o filename.ps filename.dvi
 	bash$ distill filename.ps
 	bash$ man ghostscript
 	bash$ man ps2pdf
 	bash$ ps2pdf input.ps output.pdf
 	bash$ acroread output.pdf &
         
Or you can use Ghostscript command ps2pdf . ps2pdf is a work-alike for nearly all the functionality of Adobe's Acrobat Distiller product: it converts PostScript files to Portable Document Format (PDF) files. ps2pdf is implemented as a very small command script (batch file) that invokes Ghostscript, selecting a special "output device" called pdfwrite . In order to use ps2pdf, the pdfwrite device must be included in the makefile when Ghostscript was compiled; see the documentation on building Ghostscript for details.


12.2. Convert Linuxdoc to Docbook format

This document is written in linuxdoc SGML format. The Docbook SGML format supercedes the linuxdoc format and has lot more features than linuxdoc. The linuxdoc is very simple and is easy to use. To convert linuxdoc SGML file to Docbook SGML use the program ld2db.sh and some perl scripts. The ld2db output is not 100[percnt] clean and you need to use the clean_ld2db.pl perl script. You may need to manually correct few lines in the document.

The ld2db.sh is not 100[percnt] clean, you will get lot of errors when you run
 		bash$ ld2db.sh file-linuxdoc.sgml db.sgml
 		bash$ cleanup.pl db.sgml > db_clean.sgml
 		bash$ gvim db_clean.sgml 
 		bash$ docbook2html db.sgml
         
And you may have to manually edit some of the minor errors after running the perl script. For e.g. you may need to put closing tag < /Para> for each < Listitem>


12.3. Convert to MS WinHelp format

You can convert the SGML howto document to Microsoft Windows Help file, first convert the sgml to html using:
 		bash$ sgml2html xxxxhowto.sgml     (to generate html file)
 bash$ sgml2html -split 0   xxxxhowto.sgml (to generate a single page html file)
         
Then use the tool HtmlToHlp . You can also use sgml2rtf and then use the RTF files for generating winhelp files.


12.4. Reading various formats

In order to view the document in dvi format, use the xdvi program. The xdvi program is located in tetex-xdvi*.rpm package in Redhat Linux which can be located through ControlPanel [verbar] Applications [verbar] Publishing [verbar] TeX menu buttons. To read dvi document give the command -
           xdvi -geometry 80x90 howto.dvi man xdvi 
         
And resize the window with mouse. To navigate use Arrow keys, Page Up, Page Down keys, also you can use 'f', 'd', 'u', 'c', 'l', 'r', 'p', 'n' letter keys to move up, down, center, next page, previous page etc. To turn off expert menu press 'x'.

You can read postscript file using the program 'gv' (ghostview) or 'ghostscript'. The ghostscript program is in ghostscript*.rpm package and gv program is in gv*.rpm package in Redhat Linux which can be located through ControlPanel [verbar] Applications [verbar] Graphics menu buttons. The gv program is much more user friendly than ghostscript. Also ghostscript and gv are available on other platforms like OS/2, Windows 95 and NT, you view this document even on those platforms.

To read postscript document give the command -
           gv howto.ps ghostscript howto.ps 
         

You can read HTML format document using Netscape Navigator, Microsoft Internet explorer, Redhat Baron Web browser or any of the 10 other web browsers.

You can read the latex, LyX output using LyX a X-Windows front end to latex.


13. Appendix A - Creating initrd.img file

The initrd is the "initial ramdisk". It is enough files stored in a ramdisk to store needed drivers . You need the drivers so that the kernel can mount / and kick off init.

You can avoid this file 'initrd.img' and eliminate the need of 'initrd.img', if you build your scsi drivers right into the kernel, instead of into modules. (Many persons recommend this).


13.1. Using mkinitrd

The mkinitrd utility creates an initrd image in a single command. This is command is peculiar to RedHat. There may be equivalent command of mkinitrd in other distributions of Linux. This is very convenient utility.

You can read the mkinitrd man page.

 	/sbin/mkinitrd --help   # Or simply type 'mkinitrd --help'
 	usage: mkinitrd [--version] [-v] [-f] [--preload <module>]
 	       [--omit-scsi-modules] [--omit-raid-modules] [--omit-lvm-modules]
 	       [--with=<module>] [--image-version] [--fstab=<fstab>] [--nocompress]
 	       [--builtin=<module>] [--nopivot] <initrd-image> <kernel-version>
 	       (example: mkinitrd /boot/initrd-2.2.5-15.img 2.2.5-15)
 	# Read the online manual page with .....
 	man mkinitrd
 	su - root
 	# The command below creates the initrd image file
 	mkinitrd  ./initrd-2.4.18-19.8.0custom.img   2.4.18-19.8.0custom
 	ls -l initrd-2.4.18-19.8.0custom.img
 -rw-r--r--    1 root     root       127314 Mar 19 21:54 initrd-2.4.18-19.8.0custom.img
 	cp  ./initrd-2.4.18-19.8.0custom.img   /boot
         

See the following sections for the manual method of creating an initrd image.


13.2. Kernel Docs

To create /boot/initrd.img see the documentation at /usr/src/linux/Documentation/initrd.txt and see also Loopback-Root-mini-HOWTO .


13.3. Linuxman Book

A cut from "http://www.linuxman.com.cy/rute/node1.html" chapter 31.7.

SCSI Installation Complications and initrd

Some of the following descriptions may be difficult to understand without knowledge of kernel modules explained in Chapter 42. You may want to come back to it later.

Consider a system with zero IDE disks and one SCSI disk containing a LINUX installation. There are BIOS interrupts to read the SCSI disk, just as there were for the IDE, so LILO can happily access a kernel image somewhere inside the SCSI partition. However, the kernel is going to be lost without a kernel module [lsqb ]See Chapter 42. The kernel doesn't support every possible kind of hardware out there all by itself. It is actually divided into a main part (the kernel image discussed in this chapter) and hundreds of modules (loadable parts that reside in /lib/modules/) that support the many type of SCSI, network, sound etc., peripheral devices.] that understands the particular SCSI driver. So although the kernel can load and execute, it won't be able to mount its root file system without loading a SCSI module first. But the module itself resides in the root file system in /lib/modules/. This is a tricky situation to solve and is done in one of two ways: either (a) using a kernel with preenabled SCSI support or (b) using what is known as an initrd preliminary root file system image.

The first method is what I recommend. It's a straightforward (though time-consuming) procedure to create a kernel with SCSI support for your SCSI card built-in (and not in a separate module). Built-in SCSI and network drivers will also autodetect cards most of the time, allowing immediate access to the device--they will work without being given any options [lsqb ]Discussed in Chapter 42.] and, most importantly, without your having to read up on how to configure them. This setup is known as compiled-in support for a hardware driver (as opposed to module support for the driver). The resulting kernel image will be larger by an amount equal to the size of module. Chapter 42 discusses such kernel compiles.

The second method is faster but trickier. LINUX supports what is known as an initrd image ( initial rAM disk image). This is a small, +1.5 megabyte file system that is loaded by LILO and mounted by the kernel instead of the real file system. The kernel mounts this file system as a RAM disk, executes the file /linuxrc, and then only mounts the real file system.

31.6 Creating an initrd Image

Start by creating a small file system. Make a directory [nbsp ]/initrd and copy the following files into it.

 	drwxr-xr-x    7 root     root         1024 Sep 14 20:12 initrd/
 	drwxr-xr-x    2 root     root         1024 Sep 14 20:12 initrd/bin/
 	-rwxr-xr-x    1 root     root       436328 Sep 14 20:12 initrd/bin/insmod
 	-rwxr-xr-x    1 root     root       424680 Sep 14 20:12 initrd/bin/sash
 	drwxr-xr-x    2 root     root         1024 Sep 14 20:12 initrd/dev/
 	crw-r--r--    1 root     root       5,   1 Sep 14 20:12 initrd/dev/console
 	crw-r--r--    1 root     root       1,   3 Sep 14 20:12 initrd/dev/null
 	brw-r--r--    1 root     root       1,   1 Sep 14 20:12 initrd/dev/ram
 	crw-r--r--    1 root     root       4,   0 Sep 14 20:12 initrd/dev/systty
 	crw-r--r--    1 root     root       4,   1 Sep 14 20:12 initrd/dev/tty1
 	crw-r--r--    1 root     root       4,   1 Sep 14 20:12 initrd/dev/tty2
 	crw-r--r--    1 root     root       4,   1 Sep 14 20:12 initrd/dev/tty3
 	crw-r--r--    1 root     root       4,   1 Sep 14 20:12 initrd/dev/tty4
 	drwxr-xr-x    2 root     root         1024 Sep 14 20:12 initrd/etc/
 	drwxr-xr-x    2 root     root         1024 Sep 14 20:12 initrd/lib/
 	-rwxr-xr-x    1 root     root           76 Sep 14 20:12 initrd/linuxrc
 	drwxr-xr-x    2 root     root         1024 Sep 14 20:12 initrd/loopfs/
         

On my system, the file initrd/bin/insmod is the statically linked [lsqb ]meaning it does not require shared libraries.] version copied from /sbin/insmod.static--a member of the modutils-2.3.13 package. initrd/bin/sash is a statically linked shell from the sash-3.4 package. You can recompile insmod from source if you don't have a statically linked version. Alternatively, copy the needed DLLs from /lib/ to initrd/lib/. (You can get the list of required DLLs by running ldd /sbin/insmod. Don't forget to also copy symlinks and run strip -s [lcub ]lib[rcub ] to reduce the size of the DLLs.)

Now copy into the initrd/lib/ directory the SCSI modules you require. For example, if we have an Adaptec AIC-7850 SCSI adapter, we would require the aic7xxx.o module from /lib/modules/[lcub ]version[rcub ]/scsi/aic7xxx.o. Then, place it in the initrd/lib/ directory.

 	-rw-r--r--    1 root     root       129448 Sep 27  1999 initrd/lib/aic7xxx.o
         

The file initrd/linuxrc should contain a script to load all the modules needed for the kernel to access the SCSI partition. In this case, just the aic7xxx module [lsqb ] insmod can take options such as the IRQ and IO-port for the device. See Chapter 42.]:

 	#!/bin/sash
 	 
 	aliasall
 	 
 	echo "Loading aic7xxx module"
 	insmod /lib/aic7xxx.o 
         

Now double-check all your permissions and then chroot to the file system for testing.

 	chroot ~/initrd /bin/sash
 	/linuxrc
         

Now, create a file system image similar to that in Section 19.9:
 	dd if=/dev/zero of=~/file-inird count=2500 bs=1024
 	losetup /dev/loop0 ~/file-inird
 	mke2fs /dev/loop0
 	mkdir ~/mnt
 	mount /dev/loop0 ~/mnt
 	cp -a initrd/* ~/mnt/
 	umount ~/mnt
 	losetup -d /dev/loop0
         

Finally, gzip the file system to an appropriately named file:
 	gzip -c ~/file-inird > initrd-<kernel-version>
         

31.7 Modifying lilo.conf for initrd

Your lilo.conf file can be changed slightly to force use of an initrd file system. Simply add the initrd option. For example:

 	boot=/dev/sda
 	prompt
 	timeout = 50
 	compact
 	vga = extended
 	linear
 	image = /boot/vmlinuz-2.2.17
 	        initrd = /boot/initrd-2.2.17
 	        label = linux
 	        root = /dev/sda1
 	        read-only
         

Notice the use of the linear option. This is a BIOS trick that you can read about in lilo(5). It is often necessary but can make SCSI disks nonportable to different BIOSs (meaning that you will have to rerun lilo if you move the disk to a different computer).


14. Appendix B - Sample lilo.conf

14.1. Resources on LILO

See also following documents:


14.2. Troubleshooting LILO

The beeper error codes :

Table 1. Beeper Error Codes Table

Code Description
0 PC-Speaker Defect
1 Refresh of DRAM defect
2 Paritykring defect
3 Error in the 64 basis RAM
4 Systeemtimer defect
5 Processor defect
6 Keyboard controller error
7 Virtuele modus error
8 Test from videomemory failed
9 ROM-BIOS checksumm error

2 short beeps : POST not correct. Error in a Harware test. 1 short & 2 long beeps : video error. 1) Video ROM BIOS, parity error. 2) Problem with the horizontal retour from the video adapter. 1 long & 3 short beeps: video error. 1) videocard defect. 2) wrong detection from used monitor. 3) Video RAM error. 1 long beep : POST was correct If there is a posterror, there is a hardwareproblem. Check the extentioncards for a bad contact

See also http://www.preggers.easynet.be/lilo.html

If you get problems in LILO, refer to following tips. During boot if you get error "L0101010101010101 ....", then do this

  • Use your favorite text editor to open /etc/lilo.conf
     # Find the line that reads
     linear
     # Comment it out. Change it to read
     # linear
     Save and rerun lilo.
           

  • You need to have your booting partion below the 8 gb mark. If you have a program like parition magic or Mandrake's DiskDrake utility you can easily fix this.

  • 01 is dram refresh error. When you get the L 01 simply reboot again with CTRL+ATL+DEL (but you should not power off just do ctrl+alt+del). This may correct the problem.


14.3. Sample on LILO

Always give a date extension to the filename, because it tells you when you built the kernel, as shown below:
 	bash# man lilo
 	bash# man lilo.conf
 	And edit /etc/lilo.conf file and put these lines - 
 		image=/boot/bzImage.myker.26mar2001 
 		label=myker
 		root=/dev/hda1 
 		read-only 
 	You can check device name for 'root=' with the command - 
 		bash# df   / 
 	Now give -
 		bash# lilo 
 		bash# lilo -q 
       
You must re-run lilo even if the entry 'myker' exists, everytime you create a new bzImage.

Given below is a sample /etc/lilo.conf file. You should follow the naming conventions like ker2217 (for kernel 2.2.17), ker2214 (for kernel 2.2.14). You can have many kernel images on the same /boot system. On my machine I have something like:
 	boot=/dev/hda
 	map=/boot/map
 	install=/boot/boot.b
 	prompt
 	timeout=50
 	default=firewall
 	image=/boot/vmlinuz-2.2.14-5.0
 		label=ker2214
 		read-only
 		root=/dev/hda9
 	image=/boot/vmlinuz-2.2.17-14
 		label=ker2217
 		read-only
 		root=/dev/hda9
 	#image=/usr/src/linux/arch/i386/boot/bzImage 
 	#	label=myker 
 	#	root=/dev/hda7
 	#	read-only 
 	image=/boot/bzImage.myker.11feb2001
 		label=myker11feb 
 		root=/dev/hda9
 		read-only 
 	image=/boot/bzImage.myker.01jan2001
 		label=myker01jan 
 		root=/dev/hda9
 		read-only 
 	image=/boot/bzImage.myker-firewall.16mar2001
 		label=firewall 
 		root=/dev/hda9
 		read-only 
       


15. Appendix C - GRUB Details And A Sample grub.conf

15.1. References on GRUB

See

 	bash# man grub
 	bash# man grubby   # (command line tool for configuring grub, lilo, and elilo)
 	bash# man grub-install
       
Edit the file /etc/grub.conf to make entries for the new kernel. See the sample file below:


15.2. Tips On GRUB

In Redhat Linux, during grub display, just type c for command-line option of GRUB:
 	To boot Linux do this:
     grub> help
 	  
     grub> root
         (hd1,1): Filesystem is type ext2fs, partition type 0x83
     grub> root (hd1,0)
 	  
     grub> kernel / <Press-TAB-KEY>
     This will list all files
 	  
     grub> kernel /boot <Press-TAB-KEY>
     This will list all files in /boot
 	  
     grub> kernel /boot/vmlinuz
 	  
     grub> boot
       

See also the GRUB Manual . To boot MS Windows 95/2000 etc do this: If you want to boot an unsupported operating system (e.g. Windows 95), chain-load a boot loader for the operating system. Normally, the boot loader is embedded in the boot sector of the partition on which the operating system is installed.
 	grub> help
 	grub> help rootnoverify
 	grub> rootnoverify (hd0,0)
 	grub> makeactive
 	grub> chainloader +1
 	grub> boot
       


15.3. Sample GRUB Conf File


 	# grub.conf generated by anaconda
 	#
 	# Note that you do not have to rerun grub after making changes to this file
 	# NOTICE:  You do not have a /boot partition.  This means that
 	#          all kernel and initrd paths are relative to /, eg.
 	#          root (hd0,8)
 	#          kernel /boot/vmlinuz-version ro root=/dev/hda9
 	#          initrd /boot/initrd-version.img
 	#boot=/dev/hda
 	# By default boot the second entry
 	default=1
 	# Fallback to the first entry.
 	fallback 0
 	# Boot automatically after 2 minutes
 	timeout=120
 	splashimage=(hd0,8)/boot/grub/splash.xpm.gz
 	title Windows 2000 
 	unhide (hd0,0)
 	hide (hd0,1)
 	hide (hd0,2)
 	rootnoverify (hd0,0)
 	chainloader +1
 	makeactive
 	title Red Hat Linux (2.4.18-19.8.0.19mar2003)
 		root (hd0,8)
 		kernel /boot/bzImage.2.4.18-19.8.0.19mar2003 ro root=LABEL=/ hdd=ide-scsi
 		initrd /boot/initrd-2.4.18-19.8.0custom.img.19mar03
 	title Red Hat Linux (2.4.18-19.8.0custom)
 		root (hd0,8)
 		kernel /boot/vmlinuz-2.4.18-19.8.0custom ro root=LABEL=/ hdd=ide-scsi
 		initrd /boot/initrd-2.4.18-19.8.0custom.img
 	title Red Hat Linux (2.4.18-14)
 		root (hd0,8)
 		kernel /boot/vmlinuz-2.4.18-14 ro root=LABEL=/ hdd=ide-scsi
 		initrd /boot/initrd-2.4.18-14.img
 	title MyKernel.26jan03 (Red Hat Linux 2.4.18-14)
 		root (hd0,8)
 		kernel /boot/bzImage.myker.26jan03 ro root=LABEL=/ hdd=ide-scsi
 		initrd /boot/initrd-2.4.18-19.8.0.img
 	title Windows 98
 	hide (hd0,0)
 	hide (hd0,1)
 	unhide (hd0,2)
 	rootnoverify (hd0,2)
 	chainloader +1
 	makeactive
 	title DOS 6.22
 	hide (hd0,0)
 	unhide (hd0,1)
 	hide (hd0,2)
 	rootnoverify (hd0,1)
 	chainloader +1
 	makeactive
 	title Partition 2 (floppy)
 	hide (hd0,0)
 	unhide (hd0,1)
 	hide (hd0,2)
 	chainloader (fd0)+1
 	title Partition 3 (floppy)
 	hide (hd0,0)
 	hide (hd0,1)
 	unhide (hd0,2)
 	chainloader (fd0)+1
       


16. Appendix D - Post Kernel Building

After successfully building and booting the Linux kernel, you may be required to do these additional steps to make some of the devices to work with Linux. (The steps below were tested on Redhat Linux but should work with other distributions as well.)

Video card/Monitor configuration:

  • Please see the video card manual which is usually shipped with the PC. You should look for a "Technical Specifications" page.

  • Please see the monitor's manual and look for a "Technical Specifications" page.

If you are using latest version of Linux (2.4 or later) and inside KDE/GNOME desktop click on Start->"System Settings"->Display.

For older versions of Linux follow the steps below:

You can configure the Video card and monitor by using these commands:
 	bash$ su - root
 	bash# man Xconfigurator
 	bash# /usr/bin/X11/Xconfigurator --help
 	bash# /usr/bin/X11/Xconfigurator 
 	bash# /usr/bin/X11/Xconfigurator --expert
 	See also:
 	bash# man xf86config
 	bash# /usr/bin/X11/xf86config
       
If your card is not detected automatically, then you can use the --expert option and select the "Unlisted card". If your monitor is not listed then select the generic monitor type SVGA 1024x768.

Sound card configuration:

  • Connect your external speakers to the sound card's audio port.

  • Connect your CDROM audio wire to sound card's audio 4-pin socket. (Otherwise your cdrom drive will not play the music from your music cd)

  • Refer to HOWTO docs on 'Sound' at "http://www.linuxdoc.org"

If you are using latest version of Linux (2.4 or later) and inside KDE/GNOME desktop click on Start->"System Settings"->Soundcard Detection.

For older versions of Linux follow the steps below:

 	bash$ su - root
 	bash# man sndconfig
 	bash# /usr/sbin/sndconfig
       
Then start X-window 'KDE desktop' with 'startx' command. Click on 'K Start->ControlCenter->SoundServer->General->Test Sound'. This should play the test sound. Then click on 'K Start->MultiMedia->SoundMixer->SoundVolumeSlider' and adjust the sound volume.

Network card configuration: If you are using latest version of Linux (2.4 or later) and inside KDE/GNOME desktop click on Start->"System Settings"->Network.

For older versions of Linux follow the steps below:

Configure Firewall and IP Masquerading : For Linux kernel version 2.4 and above, the firewall and IP Masquerading is implemented by NetFilter package. Hence in kernel config you should enable Netfilter and run the Firewall/IPMasq script. Download the scripts from Firewall-IPMasq scripts , main page of Netfilter is at "http://netfilter.samba.org" . Related materials at firewalling-matures and Netfilter-FAQ .

For kernel version below 2.4 you should install the firewall rpms from rpmfind.net or firewall.src.rpm .

Configuration of other devices: Refer to HOWTO docs relating to your devices at "http://www.linuxdoc.org"


17. Appendix E - Troubleshoot Common Mistakes

17.1. Compiles OK but does not boot

If the kernel compiles ok but booting never works and it always complains with a kernel panic about /sbin/modprobe.

Solution: You did not create initrd image file. See the Appendix A at Section 13 . Also, you must do 'make modules' and 'make modules_install' in addition to creating the initrd image file.


17.2. The System Hangs at LILO

Sympton: After you build the kernel and reboot, the system hangs just before LILO.

Reason: Probably you did not set the BIOS to pick up the proper Primary Master IDE and Secondary Slave IDE hard disk partition.

Solution: Power on the machine and press DEL key to do setup of the BIOS (Basic Input Output system). Select the IDE settings and set proper primary hard disk partition and slave drives. When the system boots it looks for the primary IDE hard disk and the Master Boot Record partition. It reads the MBR and starts loading the Linux Kernel from the hard disk partition.


17.3. No init found

The following mistake is commited very frequently by new users.

If your new kernel does not boot and you get -
 	Warning: unable to open an initial console
 	Kernel panic: no init found. Try passing init= option to kernel
         
The problem is that you did not set the "root=" parameter properly in the /etc/lilo.conf. In my case, I used root=/dev/hda1 which is having the root partition "/". You must properly point the root device in your lilo.conf, it can be like /dev/hdb2 or /dev/hda7.

The kernel looks for the init command which is located in /sbin/init. And /sbin directory lives on the root partition. For details see -
 	bash# man init
         
See the Section 15 file and see the Section 14 .


17.4. Lot of Compile Errors

The 'make', 'make bzImage', 'make modules' or 'make modules_install' gives compile problems. You should give 'make mrproper' before doing make.
 	bash# make mrproper
         
If this problem persists, then try menuconfig instead of xconfig. Sometimes GUI version xconfig causes some problems:
 	bash# export TERM=VT100
 	bash# make menuconfig
         


17.5. The 'depmod' gives "Unresolved symbol error messages"

When you run depmod it gives "Unresolved symbols". A sample error message is given here to demonstrate the case:
 	bash$ su - root
 	bash# man depmod
 	bash# depmod
 	depmod: *** Unresolved symbols in /lib/modules/version/kernel/drivers/md/linear.o
 depmod: *** Unresolved symbols in /lib/modules/version/kernel/drivers/md/multipath.o
 	depmod: *** Unresolved symbols in /lib/modules/version/kernel/drivers/md/raid0.o
 	depmod: *** Unresolved symbols in /lib/modules/version/kernel/drivers/md/raid1.o
 	depmod: *** Unresolved symbols in /lib/modules/version/kernel/drivers/md/raid5.o
         

Reason: You did not make modules and install the modules after building the new kernel with "make bzImage" .

Solution: After you build the new kernel, you must do:
 	bash$ su - root
 	bash# cd /usr/src/linux
 	bash# make modules
 	bash# make modules_install
         


17.6. Kernel Does Not Load Module - "Unresolved symbols" Error Messages

When you boot kernel and system tries to load any modules and you get "Unresolved symbol : __some_function_name" then it means that you did not clean compile the modules and kernel. It is mandatory that you should do make clean and make the modules. Do this -
 		bash# cd /usr/src/linux
 		bash# make dep
 		bash# make clean
 		bash# make mrproper
 		bash# nohup make bzImage &  
 		bash# tail -f nohup.out     (.... to monitor the progress) 
 		bash# make modules
 		bash# make modules_install
         


17.7. Kernel fails to load a module

If the kernel fails to load a module (say loadable module for network card or other devices), then you may want to try to build the driver for device right into the kernel. Sometimes loadable module will NOT work and the driver needs to be built right inside the kernel. For example - some network cards do not support loadable module feature - you MUST build the driver of the network card right into linux kernel. Hence, in 'make xconfig' you MUST not select loadable module for this device.


17.8. Loadable modules

You can install default loadable modules with -

The step given below may not be required but is needed ONLY FOR EMERGENCIES where your /lib/modules files are damaged. If you already have the /lib/modules directory and in case you want replace them use the --force to replace the package and select appropriate cpu architecture.

For new versions of linux redhat linux 6.0 and later, the kernel modules are included with kernel-2.2*.rpm. Install the loadable modules and the kernel with
 		This will list the already installed package.
 	bash# rpm -qa | grep -i kernel
 		
 	bash# rpm -U --force  /mnt/cdrom/Redhat/RPMS/kernel-2.2.14-5.0.i686.rpm
 	(or)
 	bash# rpm -U --force  /mnt/cdrom/Redhat/RPMS/kernel-2.2.14-5.0.i586.rpm
 	(or)
 	bash# rpm -U --force  /mnt/cdrom/Redhat/RPMS/kernel-2.2.14-5.0.i386.rpm
         

This is only for old versions of redhat linux 5.2 and before. Boot new kernel and install the loadable modules from RedHat Linux "contrib" cdrom
 	bash# rpm -i /mnt/cdrom/contrib/kernel-modules*.rpm 
 	....(For old linux systems which do not have insmod pre-installed) 
         


17.9. See Docs

More problems. You can read the /usr/src/linux/README (at least once) and also /usr/src/linux/Documentation.


17.10. make clean

If your new kernel does really weird things after a routine kernel upgrade, chances are you forgot to make clean before compiling the new kernel. Symptoms can be anything from your system outright crashing, strange I/O problems, to crummy performance. Make sure you do a make dep , too.


17.11. Huge or slow kernels

If your kernel is sucking up a lot of memory, is too large, and/or just takes forever to compile even when you've got your new Quadbazillium-III/4400 working on it, you've probably got lot of unneeded stuff (device drivers, filesystems, etc) configured. If you don't use it, don't configure it, because it does take up memory. The most obvious symptom of kernel bloat is extreme swapping in and out of memory to disk; if your disk is making a lot of noise and it's not one of those old Fujitsu Eagles that sound like like a jet landing when turned off, look over your kernel configuration.

You can find out how much memory the kernel is using by taking the total amount of memory in your machine and subtracting from it the amount of ``total mem'' in /proc/meminfo or the output of the command ` free '.


17.12. The parallel port doesn't work/my printer doesn't work

Configuration options for PCs are: First, under the category `General Setup', select `Parallel port support' and `PC-style hardware'. Then under `Character devices', select `Parallel printer support'.

Then there are the names. Linux 2.2 names the printer devices differently than previous releases. The upshot of this is that if you had an lp1 under your old kernel, it's probably an lp0 under your new one. Use ` dmesg ' or look through the logs in /var/log to find out.


17.13. Kernel doesn't compile

If it does not compile, then it is likely that a patch failed, or your source is somehow corrupt. Your version of gcc also might not be correct, or could also be corrupt (for example, the include files might be in error). Make sure that the symbolic links which Linus describes in the README are set up correctly. In general, if a standard kernel does not compile, something is seriously wrong with the system, and reinstallation of certain tools is probably necessary.

In some cases, gcc can crash due to hardware problems. The error message will be something like ``xxx exited with signal 15'' and it will generally look very mysterious. I probably would not mention this, except that it happened to me once - I had some bad cache memory, and the compiler would occasionally barf at random. Try reinstalling gcc first if you experience problems. You should only get suspicious if your kernel compiles fine with external cache turned off, a reduced amount of RAM, etc.

It tends to disturb people when it's suggested that their hardware has problems. Well, I'm not making this up. There is an FAQ for it -- it's at "http://www.bitwizard.nl/sig11" .


17.14. New version of the kernel doesn't seem to boot

You did not run LILO, or it is not configured correctly. One thing that ``got'' me once was a problem in the config file; it said ` boot = /dev/hda1 ' instead of ` boot = /dev/hda ' (This can be really annoying at first, but once you have a working config file, you shouldn't need to change it.).


17.15. You forgot to run LILO, or system doesn't boot at all

Ooops! The best thing you can do here is to boot off of a floppy disk or CDROM and prepare another bootable floppy (such as ` make zdisk ' would do). You need to know where your root ( / ) filesystem is and what type it is (e.g. second extended, minix). In the example below, you also need to know what filesystem your /usr/src/linux source tree is on, its type, and where it is normally mounted.

In the following example, / is /dev/hda1 , and the filesystem which holds /usr/src/linux is /dev/hda3 , normally mounted at /usr . Both are second extended filesystems. The working kernel image in /usr/src/linux/arch/i386/boot is called bzImage .

The idea is that if there is a functioning bzImage , it is possible to use that for the new floppy. Another alternative, which may or may not work better (it depends on the particular method in which you messed up your system) is discussed after the example.

First, boot from a boot/root disk combo or rescue disk, and mount the filesystem which contains the working kernel image:

mkdir /mnt mount -t ext2 /dev/hda3 /mnt

If mkdir tells you that the directory already exists, just ignore it. Now, cd to the place where the working kernel image was. Note that /mnt + /usr/src/linux/arch/i386/boot - /usr = /mnt/src/linux/arch/i386/boot Place a formatted disk in drive ``A:'' (not your boot or root disk!), dump the image to the disk, and configure it for your root filesystem:

cd /mnt/src/linux/arch/i386/boot dd if=bzImage of=/dev/fd0 rdev /dev/fd0 /dev/hda1

cd to / and unmount the normal /usr filesystem:

cd / umount /mnt

You should now be able to reboot your system as normal from this floppy. Don't forget to run lilo (or whatever it was that you did wrong) after the reboot!

As mentioned above, there is another common alternative. If you happened to have a working kernel image in / ( /vmlinuz for example), you can use that for a boot disk. Supposing all of the above conditions, and that my kernel image is /vmlinuz , just make these alterations to the example above: change /dev/hda3 to /dev/hda1 (the / filesystem), /mnt/src/linux to /mnt , and if=bzImage to if=vmlinuz . The note explaining how to derive /mnt/src/linux may be ignored.

Using LILO with big drives (more than 1024 cylinders) can cause problems. See the LILO mini-HOWTO or documentation for help on that.


17.16. It says `warning: bdflush not running'

This can be a severe problem. Starting with a kernel release after Linux v1.0 (around 20 Apr 1994), a program called ` update ' which periodically flushes out the filesystem buffers, was upgraded/replaced. Get the sources to ` bdflush ' (you should find it where you got your kernel source), and install it (you probably want to run your system under the old kernel while doing this). It installs itself as ` update ' and after a reboot, the new kernel should no longer complain.


17.17. I can't get my IDE/ATAPI CD-ROM drive to work

Strangely enough, lot of people cannot get their ATAPI drives working, probably because there are a number of things that can go wrong.

If your CD-ROM drive is the only device on a particular IDE interface, it must be jumpered as ``master'' or ``single.'' Supposedly, this is the most common error.

Creative Labs (for one) has put IDE interfaces on their sound cards now. However, this leads to the interesting problem that while some people only have one interface to being with, many have two IDE interfaces built-in to their motherboards (at IRQ15, usually), so a common practice is to make the soundblaster interface a third IDE port (IRQ11, or so I'm told).

This causes problems with older Linux versions like 1.3 and below. in that versions Linux don't support a third IDE interface. To get around this, you have a few choices.

If you have a second IDE port already, chances are that you are not using it or it doesn't already have two devices on it. Take the ATAPI drive off the sound card and put it on the second interface. You can then disable the sound card's interface, which saves an IRQ anyway.

If you don't have a second interface, jumper the sound card's interface (not the sound card's sound part) as IRQ15, the second interface. It should work.


17.18. It says weird things about obsolete routing requests

Get new versions of the route program and any other programs which do route manipulation. /usr/include/linux/route.h (which is actually a file in /usr/src/linux ) has changed.


17.19. ``Not a compressed kernel Image file''

Don't use the vmlinux file created in /usr/src/linux as your boot image; [..]/arch/i386/boot/bzImage is the right one.


17.20. Problems with console terminal after upgrade to Linux v1.3.x

Change the word dumb to linux in the console termcap entry in /etc/termcap . You may also have to make a terminfo entry.


17.21. Can't seem to compile things after kernel upgrade

The linux kernel source includes a number of include files (the things that end with .h ) which are referenced by the standard ones in /usr/include . They are typically referenced like this (where xyzzy.h would be something in /usr/include/linux ): #include <linux/xyzzy.h> Normally, there is a link called linux in /usr/include to the include/linux directory of your kernel source ( /usr/src/linux/include/linux in the typical system). If this link is not there, or points to the wrong place, most things will not compile at all. If you decided that the kernel source was taking too much room on the disk and deleted it, this will obviously be a problem. Another way it might go wrong is with file permissions; if your root has a umask which doesn't allow other users to see its files by default, and you extracted the kernel source without the p (preserve filemodes) option, those users also won't be able to use the C compiler. Although you could use the chmod command to fix this, it is probably easier to re-extract the include files. You can do this the same way you did the whole source at the beginning, only with an additional argument:

blah# tar zxvpf linux.x.y.z.tar.gz linux/include Note: `` make config '' will recreate the /usr/src/linux link if it isn't there.


17.22. Increasing limits

The following few example commands may be helpful to those wondering how to increase certain soft limits imposed by the kernel: echo 4096 > /proc/sys/kernel/file-max echo 12288 > /proc/sys/kernel/inode-max echo 300 400 500 > /proc/sys/vm/freepages

Оставьте свой комментарий !

Ваше имя:
Комментарий:
Оба поля являются обязательными

 Автор  Комментарий к данной статье