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Date:      Fri, 19 Jan 2007 00:47:52 +0100
From:      deeptech71@gmail.com
To:        freebsd-chat@freebsd.org
Subject:   Re: what can i do with a 486?
Message-ID:  <45B00728.5050207@gmail.com>
In-Reply-To: <200701180802.l0I82khi017603@lurza.secnetix.de>
References:  <200701180802.l0I82khi017603@lurza.secnetix.de>

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Oliver Fromme wrote:
> deeptech71@gmail.com wrote:
>  > Can you install FreeBSD on a 486 machine?
> 
> Yes, certainly.  You shouldn't expect it to be lightning
> fast, though, of course.  But it will be perfectly fine
> for a number of uses.  For example, I used to have a 486
> as my printer spooler, TFTP boot server and BBS (with an
> analogue modem) for years.  It is also sufficient e.g. as
> a router and firewall for a modem uplink.

I have a router that has some glitches, so I wanted to try out how an old 
FreeBSD system handles the routing. And I could also benefit from the fact 
that it's software... routing, VPN, network limiting/equalizing, anything i 
want :]

So.. couple of days ago I've picked up a 486 box from someone's trashcan. 
Seems to work. Some details:

an old board of some kind (intel)
   i486SX 33MHz processor
   plug for HDD, 1 for floppies, 1 for ? (havent seen anything like this)
     floppy drive
     some HDD (500MB?), has DOS + windows 3.1 on it, can boot fine
   8MB of ram
   a PCI-like slot (is it ISA maybe?),
     some card inserted, probably a slot expander (1 slot -> 3 slots)
lots of dust

> Second:  Usually such old machines only support PIO
> modes for disk access, i.e. it's _slow_ and puts a
> burden on the already slow processor.  In other words:
> You don't want to run things on the machine that require
> heavy disk access.  (Unless, of course, you happen to
> have a 486 mainboard with PCI slots so you could plug
> in a DMA-capable disk controller.)
>
> And finally, such old hardware usually has a very limited
> amount of physical memory (RAM).  Paging or swapping to
> disk isn't exactly desirable either (see the remark about
> PIO modes above).  Therefore two things are recommended:
> First, plug in as much RAM as the board can handle (you
> can get old SIMM modules on eBay), and second, compile a
> reduced kernel that contains only the things that you
> really need.  Manual tuning of various parameters (e.g.
> maxusers) instead of relying on automatic settings might
> also be worth a try.  Use "-Os -fno-strict-aliasing"
> as your CFLAGS and COPTFLAGS for compiling to reduce
> code size.  If you need to compile things on the 486
> itself, do not use the default "-pipe" option.  There
> are more things you can do to save memory; a quick search
> on Google or freebsd.rambler.ru should give some results.

Does routing need a lot of RAM? What packet throughput speed can I expect when 
it's juggling data between RAM and HDD?

> Another note:  To install the machine with sysinstall (i.e.
> from a standard installation CD), a minimum amount of RAM
> is required (I think 24 or 32 MB); the Handbook doesn't
> seem to be up-to-date on this matter).  If you don't have
> that much RAM, you either need to prepare a special CD
> for installation without sysinstall, or temporarily put
> your hard disk in another machine with more RAM for
> installation.  Once the system is installed, it will run
> with less RAM (the above mentioned requirement only applies
> to the sysinstall program).

Good idea. Thanx! I'll try that.
But doesn't FreeBSD configure things for specific hardware when installed on 
one computer? And does it work if install on a new generation 386?

> By the way, I replaced my 486 with newer hardware only for
> the reason of energy efficiency, because a 486 isn't really
> energy-saving.  My new machine (a VIA EPIA board with C3
> processor) doesn't only use less power, it's also a lot
> faster, supports DMA for disks and has more RAM, saving me
> significant amounts of time and troubles.  Unless you have
> some historical interest in that 486 machine, I recommend
> you replace it with something better, too.

I've asked some friends about old hardware, nothing. I don't want to spend 
money on buying a new board, yet. However, I may decide to do so (maybe some 
used 386s). What's better&cheaper? A quality hardware router, or a FreeBSD router?



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