Date   : Wed, 20 Jul 2011 18:27:47 +0100
From   : robert@... (Rob)
Subject: Emulating the 80186 CoPro on an ARM CoPro

On 20 July 2011 17:15, Rick Murray <rick@...> wrote:
> Yes. Hit Reply on my phone, end up PMing you. Seems to me the Reply-To
> should point to the list...?

<dons flak jacket..>


> That's the one. Had its setup via a special system disc (what, no BIOS
> config!?). Can't recall how often dozy-bloke misplaced that floppy. ;-)

onboard bios config was very rare before '486s... hence:
http://www.irrelevant.com/cc/


> But, then, my first PC was a V30-based XT with ST506 harddisc (a
> whopping 10Mb!), dual serial cards, Hercules display (!) and some sort
> of interface that looked like a SCSI socket but I never figured out what
> it was [the board said IEEE and a bunch of numbers]. So I guess from

IEEE488 - a serial bus used mainly to communicate with laboratory
equipment, but also used, in a fashion, by Commodore kit for the link
between the computer, floppy disc drives, etc.

> that, pretty much anything was going to be more compatible. Most of the
> stuff I tried looked at the graphics card and aborted with a "WTF?"
> error. ;-)

Hercules was a fairly standard option, but never got quite the support
by games as CGA/EGA etc due to it being less suitable for them!

>
>
> Conversely the PC world where supposed compatibility is accepted, but
> the big rules are innovation and cost-cutting, often at the expense of
> this compatibility. We still see it today when such-and-such an
> interface has specific behaviour depending on where it is installed, and
> what with. Example - my Presario had a TV capture card and a network
> card. But I could NOT capture video and write it to a shared folder.
> Why? Interrupts.

Ah yes,EISA and PCI shared interrupts depending on which slots
expansion cards were put in.  Sometimes you could adjust the
interrupts allocated to particular slots in the BIOS.  More usually
you couldn't. Pain in the arse.

USB is only slightly better. Except when this laptop goes to sleep,
and I wake it up, nothing connected to a USB port works any more :-(


> Apologies if there are any obvious typos. The netbook is warm, and I'm
> constantly pushing the cat off - some summer this is turning out to be.

Somewhere (more on topic) I've got a photo of my then-cat stretched
out asleep atop a BBC "B"/6502 2P combination c.1989..

Rob