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Re: [microblaze-uclinux] writeble filesystem - whitout flash
Hi Arthur,
There are many options available to you, but the easiest is probably as
follows (inspired by what flatfsd does):
1. Use a typical romfs / cramfs for your root file system (/bin, /etc,
/dev), same as usual
2. Create a mount point (empty directory) /etc/config
3. In your romfs image, have all writeable files in /etc be symbolic
links to their corresponding files in /etc/config/
4. Mount a small ext2 filesystem at /etc/config, and create the config
files there.
Look at what flatfsd does, and the supporting rc scripts in various
vendors/*/*/Makefile and so on.
The only difference between this scheme and flatfsd, is that flatfsd
recovers the contents of /etc/config from flash, on every bootup. You
will probably just want to copy from /etc/default, into /etc/config,
instead.
Regards,
John
A. Arthur Mohr wrote:
> Hello again !
>
> Thanks to everybody, looks like SSH will work this time :)
>
> The thing is SSH needs to create files, groups and users and I need to
> edit SSH's config file. As I don't want to compile a new kernel every
> time I change that file, I need to write it on the fly.
>
> As I looked in the archives, the way to go is JFFS2. BUT, that is for Flash.
> Unfortunetly, I have no flash, so I can't use it. Using only romfs is no
> good, 'cause you know it mounts a read-only fs. I tryed to use only EXT3
> and 'second extended fs support - ext2_fs, but the kernel panics.
>
> Well then ... what should I use to get a writeble fs, having only RAM to
> execute ? I dont care if I loose everything when I shut down the board,
> by now ...
>
>
> The kernel's panic message :
>
> Linux version 2.4.32-uc0 (adi_mohr@ibiza) (gcc version 3.4.1 ( Xilinx
> EDK 8.1 Bu
> ild EDK_I.17 121005 )) #24 Mon Apr 17 15:58:00 UTC 2006
> On node 0 totalpages: 65536
> zone(0): 65536 pages.
> zone(1): 0 pages.
> zone(2): 0 pages.
> CPU: MICROBLAZE
> Kernel col on UARTLite
> Calibrating delay loop... 49.76 BogoMIPS
> Memory: 256MB = 256MB total
> Memory: 257740KB available (1336K code, 232K data, 52K init)
> Dentry cache hash table entries: 32768 (order: 6, 262144 bytes)
> Inode cache hash table entries: 16384 (order: 5, 131072 bytes)
> Mount cache hash table entr
> Buffer cache hash table entries: 16384
> (order: 4, 655
> 36 bytes)
> Page-cache hash table entries: 65536 (order: 6, 262144 bytes)
> POSIX conformance testing by UNIFIX
> Linux NET4.0 for Linux 2.4
> Based upon Swansea University Computer Society NET3.039
> Incroblaze UARTlite serial driver version 1.00
> ttyS0 at 0x40600000 (irq = 4) is a Microblaze UARTlite
> Starting kswapd
> Journalled Block Device driver loaded
> xgpio #0 at 0x40020000 mapped to 0x40020000
> xgpio #1 at 0x40000000 mapped to 0x4000000SK driver initialized: 16 RAM
> disks of
> 4096K size 1024 blocksize
> eth0: using fifo mode.
> eth0: Xilinx EMAC #0 at 0x40C00000 mapped to 0x40C00000, irq=1
> eth0: id 2.0h; block id 7, type 1
> uclinux[mtd]: RAM probe address=0x301884dc size=0x9e2df000
> ucl=0
> NET4: Linux TCP/IP 1.0 for NET4.0
> IP Protocols: ICMP, UDP, TCP
> IP: routing cache hash table of 2048 buckets, 16Kbytes
> TCP: Hash tables configured (established 16384 bind 32768)
> NET4: Unix domain sockets 1.0/SMP for Linux NET4.0.
> Kernel panic: 1f:00
>
> ------------------------------------------------------------------------
> Yahoo! Acesso Grátis
> Internet rápida e grátis. Instale o discador agora!
> <http://us.rd.yahoo.com/mail/br/tagline/freeisp/*http://br.acesso.yahoo.com>
>
--
Dr John Williams, Research Fellow,
Embedded Systems Group / Reconfigurable Computing
School of ITEE, The University of Queensland, Brisbane, Australia
(p) +61 7 33652185 (f) +61 7 33654999 (m) +61 403969243
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