#### "The Linux Gazette...making Linux just a little more fun!"

# The Answer Guy

#### By James T. Dennis, linux-questions-only@ssc.com
Starshine Technical Services, http://www.starshine.org/

### Low Memory Installation

From Martin Skj\vldebrand on Sun, 17 Jan 1999

Hi,

I'm trying to install Debian from floppies on my spare lap-top.

It's an old machine, an Compaq Contura 486/ 25 with 4 MB RAM and 80 MB HDD.

The installation goes well (mostly - it complains that the swap space cannot be initialized but it still is used, swapon during startup later on goes well). But after rebooting I get various memory errors.

The latest being 'bash fork: Cannot allocate memory' when trying to do anything on the machine.

> This sounds more like there is a disk error (bad block or some such) that's somewhere in the area where you're trying to create your swap partition.

> That would explain both the initialization failure (which I presume is an error message from the installation script's 'mkswap' routine) and the bash errors.

I've read and re-read the floppy install on low-memory systems. I've expanded the swap space to about 20 MB (should be enough) but it still complains about the memory problem.

> If the error is near the beginning of the swap file/partition --- then you'll keep getting it now matter how much disk space you add to the partition.

> Try invoking the mkswap command (which should be somewhere in your startup files) with the -c option (to check for bad blocks).

Any ideas? Is it possible to run Debian on a 4 MB RAM machine?

> I don't know. That's cutting it pretty thin. I certainly wouldn't use 'bash' on a 4Mb system --- 'bash' is hardly a lightweight shell. Try 'ash' --- which is a simpler and smaller shell that's designed for use on rescue floppies, etc.

> You'll certainly want to compile a custom trimmed kernel (on another system) for use in such a constrained setting. I wouldn't think that the Contura's were so old that you can't find additional memory for them. Bumping that up to 8 or 16 Mb will make a huge difference in what you can do with that laptop. Otherwise I'd really just use it with a few DOS programs (there are DOS versions many Unix utilities). The biggest disadvantage of DOS is that you don't get any TCP/IP networking (or when you load up a TCP/IP stack --- and a few drivers for mice, CD drives etc. it eats up so much "conventional" --- MS-DOS "special" memory that you can't run anything that you care about). If you really prefer a Unix-like environment you might find a copy of Minix --- which can run on PC/XTs and can certainly fit on a Compaq.

> (Of course, a Linux kernel with TCP/IP networking and all other extraneous bits removed can boot in a little over 1Mb. This wouldn't be any normal distribution --- you'd want to use one of the micro distributions that's tailored specifically for low memory machines. For example on the "major-linux-archive-formerly-known-as-sunsite":

> > (Now known as metalab.unc.edu): we have

> http://metalab.unc.edu/pub/Linux/distributions

> ... which lists:

> > `smalllinux-0.4.0.src.tar.gz`

> ... as one of its holdings. That's a 1.2.11 kernel with patches to support ELF binaries. There was also a 1.09 based kernel with similar patches that was called "Linux-Lite" or something like that. These are likely to be better suited to use on a laptop with less than 8Mb.

> In alot of cases it depends on what you're planning on running. For example for some sorts of routers you'd want to use a newer kernel --- since it only has to run the kernel, the shell script to set up your routes and packet filtering rules and maybe a copy of syslogd (if you want to remotely log some sorts of traffic). For that you'd want a more recent kernel with a better TCP/IP stack and preferably with the more powerful IPChains packet filtering features (standard for the upcoming 2.2 kernel, available as patches to 2.0).

> Anyway, good luck. Check out for-sale news groups to see if you can find a good deal on used Contura memory modules.

M.

##### Copyright © 1999, James T. Dennis
Published in The Linux Gazette Issue 37 February 1999

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