Netboot-scratchpad - Revision history

404 Error: /* Notes on busybox */

2011-02-15T13:31:36Z

‎Notes on busybox

2011-02-15T04:39:58Z

‎Notes on busybox

2011-02-15T04:39:46Z

‎Notes on busybox

2011-02-15T03:48:58Z

2011-02-13T03:03:25Z

2011-02-13T00:22:04Z

2011-02-08T14:06:48Z

‎ext2

2011-02-08T04:09:36Z

‎Cramfs

2011-02-08T02:40:25Z

‎Cramfs

2011-02-08T02:35:48Z

@@ Line 81: / Line 81: @@
 Several defects or gotchas noted :
-# When something taken care of by BB is replaced by a "real" counterpart (e.g. copying a "real" fdisk binary instead of having the fdisk symlink pointing to BB) is run from the BB shell (ash), BB assumes it must run the internal command except when the command is run with its absolute path.
+# When something taken care of by BB is replaced by a "real" counterpart (e.g. copying a "real" fdisk binary instead of having the fdisk symlink pointing to BB) is run from the BB shell (ash), BB assumes it must run the internal command except when the command is run with its absolute path. ->
 # BB mksf.ext2 overwrites the first 1024 bytes of a partition with zeros, thus killing the Sun disklabel on it the case of the first partition starting at sector 0 (required to be bootable from OpenBoot). Core utils mkfs.ext2 leave those 1024 first bytes untouched.

@@ Line 87: / Line 87: @@
 Documented in :
-# https://bugs.busybox.net/show_bug.cgi?id=3241
+# http://bugs.busybox.net/show_bug.cgi?id=3241
-# https://bugs.busybox.net/show_bug.cgi?id=3247
+# http://bugs.busybox.net/show_bug.cgi?id=3247
 [[Category:Labs]]

@@ Line 85: / Line 85: @@
 # BB mksf.ext2 overwrites the first 1024 bytes of a partition with zeros, thus killing the Sun disklabel on it the case of the first partition starting at sector 0 (required to be bootable from OpenBoot). Core utils mkfs.ext2 leave those 1024 first bytes untouched.
+# https://bugs.busybox.net/show_bug.cgi?id=3241
 [[Category:Labs]]

@@ Line 77: / Line 77: @@
 * Tried with a ramdisk of 32 Mb, okay it boots :-)
-= Minimalistic uclibc environment =
+== Notes on busybox ==
-Having BusyBox statically linked is cool but it has a drawback : adding additional programs requires thing to be statically linked as well... So let's try to build a minimalistic netboot environment with uClibc.
+Several defects or gotchas noted :
-== Getting and compiling Buildroot ==
+# When something taken care of by BB is replaced by a "real" counterpart (e.g. copying a "real" fdisk binary instead of having the fdisk symlink pointing to BB) is run from the BB shell (ash), BB assumes it must run the internal command except when the command is run with its absolute path.
-[[http://buildroot.uclibc.org Buildroot]] is a cool thing is a set of patches and scripts that help to build environment for embedded devices. Download the latest revision (no SPARC v9 support, removed for some reasons). So Config.in.arch in ./targets should read for sparc :
+# BB mksf.ext2 overwrites the first 1024 bytes of a partition with zeros, thus killing the Sun disklabel on it the case of the first partition starting at sector 0 (required to be bootable from OpenBoot). Core utils mkfs.ext2 leave those 1024 first bytes untouched.
 [[Category:Labs]]

@@ Line 77: / Line 77: @@
 * Tried with a ramdisk of 32 Mb, okay it boots :-)
-= Mininalitic uclibc environment =
+= Minimalistic uclibc environment =
 Having BusyBox statically linked is cool but it has a drawback : adding additional programs requires thing to be statically linked as well... So let's try to build a minimalistic netboot environment with uClibc.

@@ Line 5: / Line 5: @@
 Information here may vary from day to day and  hour to hour. It is a "pad" to help us to take various notes on a future and more complete tutorial on how produce netboot images for SPARC machines. Free feel to annotate if you wish.
-= Tools =
+= Building a tftpboot image =
 * Tilo (seems a bit buggy especially with large image => segfaults)
 * Linux kernel in itself
-= The Linux kernel way =
+== The Linux kernel way ==
 * Magic command (/in /usr/src/linux) : make tftpboot.img
@@ Line 19: / Line 20: @@
 * Some Sun machines does not initialize their MMU so everything must fit in 4 Mb in their case (1 page)
-= Cramfs =
+== Cramfs ==
 * Designed for having a small footprint, ideal (to check with rw mount points ? The Fs is readonly and limited around 272Mb in size, no possibility to remount it rw...).
@@ Line 71: / Line 72: @@
 * The boot process ends with : Error -3 while decompressing! with some blocks (ramdisk is 4096 in size... too small ? overwriting problem ?) :-(
-= ext2 =
+== ext2 ==
 * Same philosophy but a volume image must be created them mounted through a loopback device then formatted....
 * Tried with a ramdisk of 32 Mb, okay it boots :-)
 [[Category:Labs]]

← Older revision		Revision as of 14:06, 8 February 2011
Line 74:		Line 74:

	* Same philosophy but a volume image must be created them mounted through a loopback device then formatted....		* Same philosophy but a volume image must be created them mounted through a loopback device then formatted....
		+	* Tried with a ramdisk of 32 Mb, okay it boots :-)

	[[Category:Labs]]		[[Category:Labs]]

@@ Line 69: / Line 69: @@
 * Build the tftpboot image => cd /usr/src/linux && make tftpboot.img
 * Put the image on a tftpserver
 [[Category:Labs]]

@@ Line 58: / Line 58: @@
 </pre>
-* Recompile a Linux kernel and put the modules in the cramfs directory sttructure (make modules_install INSTALL_MOD_PATH=
+* Recompile a Linux kernel and put the modules in the cramfs directory structure (make modules_install INSTALL_MOD_PATH=/path/to/ramdisk/tree)
+** Don't forget to put a default argument init=... (if is is suitable to keet the init deployed by busybox as is)
-* put something useful in /bin/init:
+** Put something useful in the cutomized init (can be a script) like
 [[Category:Labs]]

@@ Line 14: / Line 14: @@
 * Magic command (/in /usr/src/linux) : make tftpboot.img
 ** Scans System.map to get ELF entries (espcially _star and _end)
-* Requires a root.img file in /usr/src. This file is a ramdisk image (!= initrd ?). The smaller the better, so cramfs can be used there
+* Requires a root.img file in /usr/src. This file is a ramdisk image (!= initrd ?). The smaller the better, so cramfs can be used therem of course busybox is required.
 * cramfs must be included built-in
+* Some Sun machines does not initialize their MMU so everything must fit in 4 Mb in their case (1 page)
 [[Category:Labs]]