Arch Linux

TomB17

Member

Registered: 2009-09-02

Posts: 102

Arch on 256MB RAM / 1GB Flash system

I've got a Pentium-M system with 256MB RAM and a 1GB CF card acting as the HDD.

I'd like to install Arch, X, and a window manager of some kind on this system.

I couldn't find anything in the Wiki that seemed terribly appropriate.  It looks like this may be an application of CRAMFS but the only forum post I could find was from 2005 asking to include this module in the kernel.

Is there a document that will help me get this going?  Even something that will point me in the right direction would be appreciated.  I can install Arch but I want to make sure I don't damage the CF by too many writes.

Thanks! 

tavianator

Member

From: Waterloo, ON, Canada

Registered: 2007-08-21

Posts: 858

Website

Re: Arch on 256MB RAM / 1GB Flash system

If you want to minimize writes, cramfs won't help you as it's read-only.

What I would recommend is installing arch to the CF card, and making a couple changes to /etc/fstab:
- Add noatime to all the mount options
- Add a line to mount tmpfs on /tmp and /var/tmp ("tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0" for example)

TomB17

Member

Registered: 2009-09-02

Posts: 102

Re: Arch on 256MB RAM / 1GB Flash system

Thanks.

I had stumbled across larch and was going to try it but it looks a little embryonic and I can't get to ftp.berlios.de at the moment.

Ber

Member

From: Belgium

Registered: 2006-07-05

Posts: 80

Website

Re: Arch on 256MB RAM / 1GB Flash system

You could also take a look at unionfs and squashFS.  I did the following recently and it ended up pretty well :

- install arch the way you want it, and throw everything you don't need if you want to save space
- create a squashFS image of this root filesystem
- create 2 partitions on your CF, one being /boot
- create a custom initramfs with a /init script that eventually mounts your squashFS image and switch_root to it (you could need to add some options such as squashFS support as built-in in your kernel, or include the necessary modules in the initramfs)
- in your init script create a unionFS with 3 layers for every dir in / that you want to be writable : layer 1 the read-only dir from your squashFS image (which is now mounted as /), layer 2 with a directory present on another partition mounted (as read-only) where you want (I mounted it in /root/layer2) and a tmpfs as third layer.  This way your system can "live" in RAM without writing anything to your CF, and you can store changes to the layer 2 if you want to make a snapshot of your system at a given time.  You can very easily restore your system to "factory defaults" by erasing all content of layer 2.  AT every boot, your system will appear as the sum of layers 1 and 2, and the files being present on both are taken from layer 2

If you're interested and need some help don't hesitate to contact me.  You can easily find doc with some keywords from my little and obscure explanation.

It's not necessarily the easiest way, but it's definetely an interesting thing to do!

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