From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Given <dg@cowlark.com>
Subject: Re: Help Wanted!
Date: Tue, 27 Sep 2005 22:48:14 +0100
Message-ID: <200509272248.17224.dg@cowlark.com>
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On Tuesday 27 September 2005 22:06, Hans wrote:
[...]
> Why not?

The short answer is because the BIOS is not reentrant, which means it can o=
nly=20
do one thing at a time. Remember the bad old days when accessing the floppy=
=20
disk would make the system freeze? That's the BIOS' fault.

Also, the BIOS is *extremely* basic. The BIOS elevator algorithms for MFM h=
ard=20
disks sucked hugely; I once ran big Linux on a 386 with an MFM drive, and w=
as=20
amazed at just how much faster Linux' disk access was, simply because it wa=
s=20
scheduling the I/O transfers more efficiently. I'm not even sure the BIOS=20
does DMA. Remember that the B stands for Basic...

Now, it *might* be possible to multitask during a BIOS call provided only o=
ne=20
task was accessing the BIOS at any time. You still wouldn't be able to, e.g=
=2E,=20
access the hard disk while the floppy drive was in use, but at least the=20
system shouldn't just freeze.

[...]
> I would forget about ARM since they have a very good uCLinux port and gcc
> support.

Yeah, but uCLinux is still very large compared to an ELKS kernel.

(BTW, someone has told me via email that they have Minix 2 running on a i86=
=20
machine, but the TCP/IP stack tends to eat most of the available memory. So=
=20
it does actually work.)

=2D-=20
+- David Given --McQ-+ "Information wants to be free, but my mail client
|  dg@cowlark.com    | does not want to be chock-full of herbal pot
| (dg@tao-group.com) | alternative spam." --- Sant Lupus on Slashdot
+- www.cowlark.com --+=20


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