On Wed, 25 Apr 2012, Greg Ungerer wrote:

On 04/25/2012 05:22 AM, Rob Landley wrote:

On 04/18/2012 10:25 AM, Gross, Mark wrote:

I'd like to see Linux fit in stuff that this too :
http://olimex.wordpress.com/2012/04/04/unix-on-pic32-meet-retrobsd-for-duinomite/

Linux in under 2 megabytes of RAM, even when running from ROM, is not a
realistic goal. For context: linux 0.0.1 was developed on a 4 megabyte
system in 1991. Swap support was added in december of that year so it
could run on a 2 megabyte system.

For further context. The first versions of Linux on ColdFire (so
uClinux, non-MMU) I ported and put together ran in 1MB of RAM on the
Arnewsh 5206 ColdFire boards. I still have the binary images I ram
online at http://www.uclinux.org/ports/coldfire/binary.html. (So that
was around year 2000).

That was a 2.0.38 kernel, with a serial driver and network driver
configured - and not much else. That 1MB also contained a RAM root
filesystem (ie it network loaded, didn't run from FLASH). Looking
at the image file the kernel load binary was about 305k and there
was a 75k ramdisk attached to it.

You couldn't really do a lot in userspace - but it ran, you had a
basic shell to operate. (And all this without shared libraries :-)

So it was once possible to have a Linux system in 1MB of RAM.

And on the MMU front: I once limited Fast RAM on an Amiga to 2 MiB, and
booted Linux into X with twm and xterm. The 2 MiB did not include frame buffer
memory, as that's part of Chip RAM. This was just my day-to-day kernel, so
networking was enabled. Obviously swapping was enabled, and it was dog slow ;-)

So it was once possible to have a Linux system in 2 MiB of RAM.

With kind regards,

Geert Uytterhoeven
Software Architect
Technology and Software Centre Europe

Sony Belgium, bijkantoor van Sony Europe Limited.
Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium

Phone: +32 (0)2 700 8453
Fax: +32 (0)2 700 8622
E-mail: Geert.Uytterhoeven@...

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