Did they punt the 6847+SAM in the COCO3?
Dick
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <classiccmp(a)classiccmp.org>
Sent: Wednesday, April 24, 2002 4:26 PM
Subject: Re: Micro$oft Biz'droid Lusers (was: OT email response format)
>
> I haven't looked at the insides of the COCO2 I've got sitting here, but I
> don't see any place for a FDD or a HDD. Are there serial ports anywhere
that
On the right hand side of the main PCB is an edge connector, officially
called the 'cartridge port'. Although originally designed for ROM
software cartridges, it's essentially the 6809 system bus, and you can
connect an FDC or HDC here (both were sold by Radio Shack, BTW)
As for serial ports, there's a bit-banger built into the machine (it's
the 4 pin DIN socket on the back of the PCB). As a bitbanger, it's best
used for output only (to drive a serial printer, for example), but I used
OS-9 as a 2 user system with a 300 baud terminal connected there for a bit.
More reasonably, you'd connect an 6850 or 6551 to the cartridge
connector. There was a Radio Shack cartridge to do this (also containing
a dumb terminal emulator in ROM). Hardware hackers built multiple serial
port cartridges, particularly if they ran OS-9 seriously.
There's also a think called a Multi-Pak interface that connects up to 4
cartridges at the same time. It was common to use one of these to connect
an FDC, HDC and serial cartridge to the CoCo.
I can use? How much R/W memory does it have?
How do you expand it to do
CoCo 1 : 4K, 16K, 32K (or 64K with simple mods)
CoCo 2 : 16K or 64K
CoCo 3 : 128K or 512K
> something useful?
>
> ... see what I mean? You have to do so much to the thing that RS sells
you
> that it takes up a whole tabletop just to get to
what's in the PC's box,
and
Well, the fact you can buy it in sections is actually an advantage if you
can't afford it all at once. I bought the CoCo first, then the disk drive
and OS-9 about 6 months later. And I then built my own multi-pak
backplane and serial ports.
And it's not impossible to repackage the CoCo into a PC-clone case.
Plenty of people did.
> The worst you have to do with a PC, PDP11, or whatever computer you buy,
is
plug in what
you want to use.
Ditto with the CoCo if you bought all the Radio Shack hardware you
needed. Just plug the multi-pak into the CoCo, then plug in a disk
controller and serial port, etc.
I ran OS-9 on my CoCo for many years. It was the first multiuser system I
owned, and I learnt a heck of a lot from it. And it cost me a lot less
than any PC clone at the time.
>
> With the COCO, you're better off starting from a wirewrap panel and a
bucket
of parts,
since the video on the COCO is not "up to snuff," i.e. 80x24
characters-capable. It uses that ridiculous 6847, IIRC, and even at 32
To be honest, I'd rather use OS-9 on a 6809 from a teletype than (say)
MS-DOS on an 8088 and a 80*24 video display. Video performance is not
something I care too much about on a _computer. In any case firstly you
could use an exernal video terminal with the CoCo under OS-9, And
secondly the CoCo 3 has an 80*25 text mode.
-tony