That's not exactly what I said, though it may have seemed that way. What I
said was that the basic unit wasn't much more than a toy, since the EI and
disk drives didn't come out until some time after the TRS-80 became avaiable.
The Radio Shack experience was pretty much the first one of its kind, i.e.
they put out what they thought met their "most likely to sell" criteria,
though they were pretty wrong about the concept in several respects, all
associated with packaging. They figure that out and fixed most of the
problems in the Model 3. They didn't fix all the problems, of course, such as
that inane display format and the slow cpu, but, they got the packaging
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
Sent: Friday, April 26, 2002 5:55 PM
Subject: Re: expansion differences (was Re: Micro$oft Biz'droid Lusers)
> > That certainly applies to all those
computers you claim are 'toys'. I
> > don't think you ever had to write code yourself to get the
> > computer-manufacturer's disk drive to boot/run the
> > computer-manufacturer's chosen OS. Certainly not with the Apple ][,
> > TRS-80 (any version), C64, Pet, etc. You just plugged it all together
The Apple][ didn't really need a lot of plugging. It was designed to be a
computer, though its predecessor, the Apple I had signal names on its
I really can't see why you claim the Apple ][ was designed as a computer
and the TRS-80 (say) was not.
The obvious distinction is in that the Apple ][ was intended to be expanded
with cards you could buy. Like the other "toy" vendors, which came along
somewhat later, RS figured you should buy expansion hardware exclusively from
them, so they didn't provide a generalized expansion interface, but, rather,
just the memory and limited I/O expansion they thought appropriate. This
follows the same model as the later "toy" makers, but the TRS-80, based on
their advertising and other features, didn't intend the majority of their
users to be gamesters, exclusively. Most notably, this is illustrated by
their inclusion of the ROM basic.
FWIW, to add a disk drive to the Apple ][, you :
Plugged the disk drive cable into the disk interface card.
Pulled the top off the apple, plugged the disk interface card into an
expansion slot, put the top back on.
Put the DOS disk in the drive and turned on the Apple.
To add a disk drive to the CoCo, you :
Plugged the disk drive cable into the disk interface cartridge
Plugged the cartridge into the side of the CoCo.
Turned on the machine (the OS -- really extensions to BASIC to allow you
to load/save programs and data, format disks, etc -- was in a ROM in the
cartridge so you didn't need a boot disk).
If you wanted to run OS-9 you stuck the disk into the drive and typed
I can't see much difference between those 2 upgrades...
one difference between the two "models" that were followed was that the
became avaiable quite some time before any expansion hardware was available.
This follows the same model as the Commodore machines and a few others, whose
vendors seemingly figured they'd sell the main box to raise money to fund the
development of the expansion hardware if there was going to be any. In many
cases, this was a great favor to the purchasers, since they immediately could
begin to see what they'd bought. If it was useful to them, they stuck with
it, if not, well, instead of having a couple of k-bucks invested, they only
had a few hundred and could move on to something that they liked better.
> schematic that clearly indicated it was intended as a video device more
> as a general purpose computer. That was probably
> had to be slaved to the video refresh timing.
The TRS-80 was in the
nearly a year
before the expansion interface, disk drives, and OS were
Was the Disk II avaiable as soon as the Apple ][ was released? (I don't
know the answer, Sellam?)
I don't think so, but it wasn't long after the ][ came out. Most of the
I saw were actually ][+'s.
available. I don't know what the story on
the PET was, as there were no
outlets for them here in the Denver area that kept 'em in stock. They
IIRC, the very first version of PET BASIC had a bug in it which meant the
only mass storage you could use was the cassette recorder.
> > > When you opened the box with your COCO, what useful work would it do
> > Depends on what you consider useful work :-)
> > > $399 you had just spent? Could you write a letter? Could you write
> > Write a letter? There was a word processor ROM (Color Scripsit Program
> > Pak) that you could plug in. I have it somewhere. I think it came out
> > long after the CoCo itself
> The latter was my point, though in any case, it wasn't included in the
> bundle. The hardware preceeded any useful
application, though it was
Apart from pre-packaged business systems, very few micros came with word
processing software. It was always an optional extra.
Yes, but if, by way of comparison, you bought an Ampro "Little Board"
only preceeded the CoCo by a few months (?), you had your choice of several,
aside from the line-editor that came with the OS, which was included with the
Little Board. I don't remember what inexpensive 2-sided 5-1/4" drives cost in
'83, but I do remember that the Ampro could use the already-available
distribution disk format of the Kaypro and Osborne machines, though it wasn't
native to Ampro.
> long after there were microcomputers with plenty of useful software
> While I've never maintained that the
"$399" CoCo was incapable of anything
> enough equipment was added, it's clear that
you can't compare the CoCo as
> purchased in, say '82, if it was even available that early, with a
> system, e.g. the Ampro Little Board, costing, I
think <$200 (as a kit, of
> course) including the OS on floppy disks. It required a serial terminal,
> course, but provided the ability to run anything
CP/M. As usual with
> 5-1/4"-diskette-based systems, there was a media issue, but that could be
ed out by
means of Modem7.
So, you needed to buy the Little Board, a serial terminal, at least one
disk drive (I can't believe $200 included the drive), and probably a PSU
and a case. And then get it all working. Fine if you knew what you were
doing. Not so good if you were starting out.
And presumably using Modem7 to transfer programs from 8" disks (the
_only_ standard CP/M format) to the Little Board implied you had another
CP/M computer with 8" drives. You know, this is starting to sound expensive.
Well, if you bought a new terminal, it meant an outlay by 1983 of somewhere on
the order of $550. If you got one second-hand, $100 might do it. If you
wanted to use a modified TV-set, Digital Research of Texas (Ferguson) (the
guys who sold the BigBoard) sold a ~6"x8" board that allowed you to do that,
and you had to provide a parallel-interfaced keyboard. Those were pretty
cheap too, certainly more so than today. Frankly, I suspect the BigBoard was
a better buy if you intended to use a TV and a keyboard, since the display
circuit was already on the board. What's more, it worked with 8" drives,
which were, after all, the CP/M standard, so there's another option.
> > > compile a Fortran program? Could you save your work in any meaningful
> > I know of no home computer that had Fortran in ROM. The CoCo (of course)
> > had a BASIC interpretter in ROM, so you could type in and run programs
> > (it came with a fairly good BASIC tutorial manual).
> ROM wasn't the issue. The fact that the CoCo would run only software on
You clearly don't know much about the CoCo.
The CoCo could run software from RAM (of course). In fact it was one of
the few micros at that time which had both BASIC in ROM and the ability
to 'turn off' the ROM and have a memory map that was almost entirely RAM
(the only exception being the I/O devices). Most machines had either
BASIC In ROM that was always there (and which got in the way if you
wanted to run a real OS), or just had a little boot ROM (which was often
'turned off' after the OS had been booted), but which therefore needed a
disk drive to work at all.
There was a fair amount of CoCo software sold on ROM Paks because they
were quicker to load than cassette tapes (they were also harder to
pirate...). But you certainly could run software loaded from tape (I have
a few CoCo games that were sold on cassette).
My recollection of the CoCo, quite limited for sure, since it wasn't very
widely popular around here, but one of my colleagues had one, suggests that
the appearance of runnable code for the CoCo was not contemporaneous with its
introduction. My recollection is that there wasn't much available in terms of
expansion hardware or ROM software until the CoCo was no longer particularly
important on the market, not that it ever was. However, the PC came down in
price to where one could have a complete PC/XT clone for well under $1k by
1985, which badly hurt the makers of machines like the CoCo, etc.
> puts it in a different category than that of a general purpose computer,
> it only became after the addition of additonal
hardware. That, BTW, was
> In 1983, which was the last year in which I purchased any CP/M software,
> had no fewer than 6 different 'C'
compilers, 4 Pascal compilers, 2 Fortran
> compilers, PL/1, 3-4 BASIC interpreters and compilers, several assemblers,
> a number of cross-assemblers, not to mention many
other tools of various
> sorts. None of these were on ROM. All were from different vendors and
So? The CoCo had plenty of software available if you added a disk drive
an OS-9. Presumably all the software you mentioned also needed at least
one disk drive.
Yes, but when?
It sounds as though you are moaning that the CoCo was not a CP/M machine.
Well, of course it wasn't. It used a 6809 processor. If you wanted a CP/M
machine, then fine, buy one. But OS-9 was a much nicer OS than CP/M (I've
used both seriously...) OS-9 felt more like unix (yes, I know it was very
different internally). And the I/O system was nothing short of beautiful
(I wish it was as easy to write device drivers for other OSes). If you
added a piece of homebrew hardware to the CoCo (let's say a parallel
printer interface), then you could write a device driver in a few lines
of assembly code, assemble it, load the resulting 'module' at the command
prompt and have the device available to all programs on the system. Now
of course you don't like unix (and prefer MS-DOS) which might explain why
you also prefer CP/M to OS-9
> Unfortunately, by the time you could buy a complete, OS-9-ready CoCo
> I'd bet you could by an MS-DOS capable system
for about the same money
You probably could. But I actually chose a CoCo 3 system over a PC-clone
for a birthday present one year. And I have _never_ regretted it.
> > The serial port was intended to be used as a printer port. For some
> > reason it ran at 600 baud by default, but.... I suppose you believe that
> > all printers have a parallel interface? I do not!
> The serial printers of the time seemed to work fine at low baud rates
> they were most often the daisywheel types. Those
cost WAY more than a
save money on a $399 CoCo would have wanted to pay.
There were plenty of cheap-ish serial dot matrix printers around at the
> > > CPU chip and start from scratch rather than having to work around all
> > > stupid, Stupid, STUPID hardware they
used? ... hardware you had to
> > Actually, the CoCo hardware was pretty nice, apart from the display (you
> > seem to regard this as being the most important part of a computer, I do
> > not). The hardware did _not_ generally get in the way of homebrew
> > (I speak from a lot of experience here,
I've built all sorts of add-ons
> > for the CoCo).
> It IS the most important part of the computer, since it's what you saw.
Sorry, I have to disagree with you there. Many of my computers don't even
have any form of video output. The think I look for when choosing a
computer is the _processor_ and _OS_.
I've long (very long) considered a display of fewer than 24 lines of 80
characters pretty useless. True, 80 column lines in pages of 24 date back to
the U.S. military "coding forms" developed in the U.S. Navy and later
proliferated throughout the industry. It seemed to me to be one of a very few
things the military got right.
> user interface seems, still, to be the primary issue in deciding on one
> over another for home use. It's like the
speakers in your sound system.
> normally tell people to spend at least half their
home stereo budget on
> speakers, half the remainder on their receiver/amplifier, and the
Seems reasonable. But that's because the purpose of a Hi-Fi system is to
produce sound with minimal distortion, and most of the distortion comes
from the speakers. The purpose of a computer is not just to output video.
It's to do processing as well.
True, but it's got to tell what the outcome of your processing task was.
> > There was one big advantage to starting from a home computer rather than
> > just a CPU chip. You had a 'base system' that included enough software
> > PEEK/POKE bytes to your homebrew add-on for
testing. That alone made
> > a lot easier when you were starting out.
> If you were smart enough to build anything at all. you were smart enough
get a monitor
program for some other system and build your hardware so it
could execute that monitor. You had to start with something. True, a
Well, if you're just starting out you have to get a lot right just to run
that monitor. All the bus connections correctly wired and no shorts. CPU
clock running. Memory map as you (and the monitor ROM) expect it. ROM
correctly programmed. I/O devices where the monitor expects them. And so on.
None of this is impossible, or even that difficult. But for a first time
project there's a lot that can go wrong, and you might well then not know
how to look for the problem. If you started with a CoCo (or whatever) you
had a base machine that would work. If your device stopped the machine
from even starting up it was a fair bet you'd got a short between 2 bus
lines. If it didn't repsond to the right addresses, you'd mis-designed
the address decoder. And so on. It was a lot easier to get your first
hardware project working that way.
removing the CPU and using switches to set the addresses was an easy enough
way to check whether a CPU communicated properly with an I/O decoder and the
downstream hardware. It wasn't instantaneous, but it didn't take long to set
8 addresses. I could have taken the thing to work and used the 'scopes and
other lab equipment, but I got it working without them. Later on, I was
occasionally seen to bring my computer to work so I could use it there as a
tool to stimulate or monitor other hardware.
I guess I consider it pretty simple because that's how I got my first computer
working. I took a memory map from an existing architecture and, because I was
too impatient to wait for boards to become avaiable, I built my own from
wirewrap materials. It took a weekend and, when I was done, it worked. I'd
built a small box, about 6" tall with a small SONY TV-set in it and a PSU in
it, and mounted a 12-slot passive backplane in the thing, and away we went.
I'd picked an architecture for which software and hardware already existed, so
I could replicate what I needed and steal the driver and application software.
That was before disk drives were cheap, so it used an audio cassette for
storing and retrieving data. It didn't take me long to tire of that.
resident ROM was handy, provided you could make
it go away.
You could. Look at the SAM data sheet.
I was hoping to avoid that ...
> > Well, I guess the Multi-Pak was designed to have 4 cartridges plugged in
> > at once so you didn't have to keep on unpluging them when you wanted to
> > change programs. But I can assure you that most of them were used as
> > expansion backplanes so as to have the disk controller, serial port and
> > couple of other hardware add-ons plugged in
at the same time.
> That's something I wasn't aware of, though I still maintain that RS really
> didn't intend for it to be used for 3rd party hardware. They certainly
At least in the UK you could buy 'off the rack' in the local Tandy shops
(Radio Shack Stores :-)) prototyping boards to fit the CoCo cartridge
port (basically a PCB with a gold plated edge connector at one end,
power/ground distribution and pads to fit standard DIL packages) along
with plastic boxes to take that board and fit nicely into the CoCo or
MultiPak. So it appears they _did_ expect you to do some homebrewing.
Homebrewing fit their business model at the time, but, aside from the fact the
IBM PC was taking over the world of microcomputing, there still wasn't much
interest in 8-bitters that took up a whole table top. The last major trend in
CP/M computers, for example, was typified in the move from
box+terminal+drive_box+hard_drive_ box to luggables such as the Kaypro,
Osborne, and Otrona. In '84 I had a pretty big system at the house, but
hauled a modesltly proportioned barebones system based on the Ampro with me
wherever I went, and it had a hard disk and a floppy, along with an integrated
display (using the small Ferguson Engineering terminal board) all crammed into
a box about as large as an Otrona. It didn't have a handle or an attachment
for the keyboard, both of which would have been convenient. I doubt much of
their competitors' hardware was available in the Radio Shack.
One of my client companies sold an OS for the TRS-80, called NewDOS-80. I
doubt it pleased the RS guys to have people ask for it in their stores.