> Date: Wed, 28 Mar 2001 19:36:07 +0100 (BST)
> From: ard_at_p850ug1.demon.co.uk (Tony Duell)
> Subject: Re: ZX80/81 expansion
>
> > My ZX80 came with a ZX81 16K RAM pack and it works fine;
> ISTR physical
> > differences aside the only real difference between the 80
> and 81 was the ROM
>
> I thought the ZX81 hardware provided some kind of interrupt
> to the Z80 to
> allow for 'simultaneous' processing and display, and that you
> couldn't
> get this on the ZX80 simply by dropping in the new ROM. There were
> various circuits (a couple of TTL chips IIRC) to add this
> feature to the
> ZX80, though.
Yah, the ZX80 couldn't think and talk at the same time so it blanked the
screen while it was processing! In the ZX81 this was known as FAST mode,
with the slower SLOW mode being able to do both. However, this still meant
that in SLOW mode the machine was 4 times slower than in FAST! Probably
sometime tonight I'll upload the Your Computer reviews of the ZX81, Jupiter
Ace and a couple of others for your reading pleasure, unless you've already
got them round somewhere. Oh, hang on, you're text only aren't you?
> Keyboard overlay I think. The keyboards were somewhat different
> physically, weren't they -- the ZX80 used contacts on the
> main PCB, the
> ZX81 had a separate membrane keyboard linked up with tapewire.
<thinks>. Yep. Looking at the pic on the museum site the keyboard is part of
the main PCB, whereas on the ZX81 it was separate. I still think its funny
to look at the design for the ZX80 and compare it with the heath-robinson
nature of the Issue 1 Spectrum :o)
> I have an Ace, but it's not 'spare' if you see what I mean.
Bugger :)
> ------------------------------
>
> Date: Wed, 28 Mar 2001 22:21:07 +0000
> From: jpero_at_sympatico.ca
> Subject: Re: MacOS on CD-ROM? (was Re: Mac SE/30)
>
> The biggest difference this Basilisk II is freeware where other
> emulators you talked about ( saw them ) are payware.
I think I need to get my paws on that then......
--
Adrian Graham MCSE/ASE/MCP
C CAT Limited
Gubbins: http://www.ccat.co.uk (work)
<http://www.snakebiteandblack.co.uk> (home)
<http://www.binarydinosaurs.co.uk> (The Online Computer Museum)
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Received on Thu Mar 29 2001 - 03:05:56 BST