installing core udebs
Im not exactly sure what the current plan is for getting the core udebs
on the boot disk, but how does this sound.
Use an initramdisk, linuxrc is a static version of busybox with the
following features.
#define BB_CHROOT
#define BB_DPKG
#define BB_GUNZIP
#define BB_INSMOD
#define BB_LINUXRC_DI // This a custom initrd for the debian installer
(more below)
#define BB_MKSWAP
#define BB_MOUNT
#define BB_RM // This is needed for BB_DPKG (i need to document it)
#define BB_SWAPONOFF
#define BB_TAR
Compiled statically against uClibc these features come to about 80KB
(44KB after gzip -9)
The purpose of this busybox based linuxrc program is to setup the root
filesystem on the shm filesystem (or ramfs if we still want to go that
way).
Its still at planning stage, but im thinking of the following steps.
1) mount procfs under /proc
2) mount shm under /dev/shm, (if we use devfs this is done
automatically)
3) load any kernel modules found in the initrd filesystem
4) mount the filesystem of the boot medium (e.g. /dev/fd0)
5) search for, unpack and insert any core kernel_module*.udebs found
here.
6) scan /proc for a list of storage devices
7) try and automount detected storage device partitions
8) create swap file or swap partition and use it. //PROBLEM, lowmem
machines a) with no existing partitions and only one drive, or b) with
partitions but no space will have problems past this point
9) search mountable partitions for *udebs
10) install found udebs under /dev/shm
11) pivot_root to /dev/shm
12) finish initrc and continue with a normal busybox init based in
/dev/shm.
If we do this then the boot medium could look something like
/dev/fd0 is formated with cramfs (maybe vfat as an alternative?),
contains
/initrd.tar.gz (contains the initrc image)
/bzImage (the boot kernel)
/kernel-modules*udeb (kernel modules that need to be installed to create
a swap partition, i.e. fs, scsi or ide modules)
/rootskel*udeb
/cdebconf*udeb
/busybox*udeb
/libc*udeb
....
other core udebs
....
the initrd.tar.gz
The fileystem driver to suit this fs must be statically compiled into
the kernel
If the filesystem on the boot medium is a module it must be contained in
here.
/linuxrc /* static against uClibc */
/dev
/proc
not much else
To prepare the boot disk we just need to copy a kernel, initrd and a
bunch of udebs onto a disk, easy for end users to make custom disks.
This setup would mean that the initrd would be isolated from anything
else in the system, once it was working it wouldnt need much maintanance
at all.
If we had updates for core udebs they could be placed on seperate medium
(hdd, floppy) and dpkg could install them rather than older version of
the udebs that may be on a crusty old cd.
The custom linuxrc wouldnt take mushc work, it would be mostly just
combining the functionality from other busybox applets.
It would work for machines with low mem.
How does it sound for a plan ?
Glenn
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