Installing on old machine

NotQuiteSane · Posted: Wed Nov 02, 2005 5:39 pm Post subject: Installing on old machine

I have a Pac bell "legend 300SX". looked it up before, but I belive it is a 386SX 20mhz. maxes out at 16mb of ram.

I have been contamplating (nothing more since I need to find more memory first) putting freesco on it.

However, there are some issues with freesco that are bothering me, and I'd like to try to install gentoo with a 2.6 kernel. I Know that linux can be installed on as low as a 386SX 16 / 4mb, but, can I install 2.6 based gentoo on this box? I intend to offload via NFS everything possible (including swap) to a different machine.

the box would be a firewall / router / ssh server only. install would be onto a CF card via ide adapter

so can it be done? or is a 386 just too old?
NQS
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NeddySeagoon · Posted: Wed Nov 02, 2005 7:55 pm Post subject:

NotQuiteSane,

Hmm. I have a 386SX with 13Mb RAM. It took all day to do a network install of Red Hat 6.1 with all the options off.
Setting up ISA cards can be a challenge too.

If you don't have the 387SX Maths co-processor, you will need a kernel with Maths Emulation to even get started.
They are rare today.

You can build on a different machine for the 386SX target, then move the HDD back to the 386.
Using root and swap over NFS is not a good idea on a firewall, since any breakins would get to the NFS host.
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Computer users fall into two groups:-
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NotQuiteSane · Posted: Thu Nov 03, 2005 8:10 am Post subject:

NeddySeagoon · Posted: Thu Nov 03, 2005 8:18 pm Post subject:

NotQuiteSane,

You need a kernel with Maths Emulation compiled in. Most kernels today omit that. (Yes the option is still in 2.6). They assume you have an on die co-processor, which started with the 486DX. You will need a kernel built for a 386 with Maths Emulation included to even boot.

Swap over a 10Mbit/sec network will be painfully slow. You may get data rates as high as 1MB/sec.
You only have ISA slots and 100Mbit network cards were not made in ISA, with the exception of a few weird non standard point to point links. I understand the wear issue on flash memory, and why you want to move swap, /tmp and /var away from flash.
Sharing things over NFS is not generally secure, so if your firewall was compromised you would be making it easier for an attacker to get into the NFS server.

Your install method is sound.
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Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

NotQuiteSane · Posted: Sat Nov 05, 2005 5:14 am Post subject:

I "solved" the problem. found a scrap 486sx/25 that has pci slots and takes 72 pin sticks. got 96mb in it now, but I'm gonna look for both 64 and 128mb sticks, give me between 256-512mb, which should be enough to elminate swap. still got to worry about /tmp and /var, I'm considering SHFS for those, but the one write at a time has me a bit worried. perhaps, if there is enough memory, put them on tmpfs, and use a cron job to write /var to the CF

if I write /var to flash every half hour, i calculate a 5 year life time, by which time the 1 mil write CF card should be out

NQS
_________________
These opinions are mine, mine I say! Piss off and get your own.

As I see it -- An irregular blog, Improved with new location

To delete French language packs from system use 'sudo rm -fr /'

NeddySeagoon · Posted: Sat Nov 05, 2005 2:13 pm Post subject:

NotQuiteSane,

Thats a big step in the right direction. The 486SX still does not have a floating point processor.
The original 486SX chips were actually 486DX that failed testing for floating point operations. Some were marginal fails and worked OK in practice. Later, Intel took the FPU out and made real 486SX chips.
If you have a 486SX in a ceramic pin grid array, it may be one of the early ones with an almost working FPU. If its in a plastic package, with wires on all four sides, the FPU has been surgically removed.
Most real 486SX motherboards were made with an upgrade socket for a 487. The 487 is just a 486DX with an extra pin thats used to turn off the soldered in 486SX.

The life of your flash may be better than you think. Flash life was at 100,000 writes before wear levelling was introduced.
The file caching carried out by the kernel will help too. 96Mb should be enough to avoid the need for swap.
/usr can be read only, as can root if you make /etc/mtab a symbolic link to /proc/mounts.

There is a special filesystem for flash - JFFS2 I think, you may want to look into that.
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Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

pjp · Administrator Joined: 16 Apr 2002 Posts: 20067

Moved from Other Things Gentoo
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djpharoah · Posted: Sat Nov 05, 2005 9:17 pm Post subject:

wow..486sx cpu
that was my first pc back in like '89..if you succeed i will attempt it on this pos i have under my bed at home.
its a 486 of some kind..would do it just for fun..

btw gl

NotQuiteSane · Posted: Sun Nov 06, 2005 5:20 am Post subject:

NotQuiteSane · Posted: Sun Nov 06, 2005 5:29 am Post subject:

NeddySeagoon · Posted: Sun Nov 06, 2005 12:52 pm Post subject:

NotQuiteSane,

This page and some of its links tells you all you need to know about your board.

The reason it doen't have an upgrade socket is that it has a ZIF socket for the CPU, that marks it as a very late 486 board.
It also has the level 2 cache on a stick, rather than DIL sockets. Maybe it is a DX chip after all?

NotQuiteSane · Posted: Mon Nov 07, 2005 2:37 am Post subject: