Introducing myself - Commodore PET

From: Bob Lafleur <bob_lafleur_at_technologist.com>
Date: Sun May 12 03:33:48 2002

In late 1977, I began to hear about small computers that could fit on a
tabletop. My grandfather, who was a very generous man, used to take me
on Saturdays to various places, such as shopping, to the airport to
watch the planes, etc. and one day I suggested we might go check out a
new ?computer store? that had opened in Windsor Locks, CT (about 20
miles from my home). We went there several times, and marveled over the
computers they had for sale (I believe they initially had Altair
computers, and eventually started selling the Apple II). The Apple II
seemed quite interesting, but was also quite expensive (for a 14-year
old). Somehow we heard that a local store (called NEECO, which stood for
New England Electronics Company, and primarily sold calculators) would
soon be getting a new ?computer? in that was made by Commodore. Each
week or so I?d stop in and see if they had it yet, and each week the
answer was ?not yet, we?re still waiting?. Finally, they got one, and
they gave me a demo of it. I couldn?t believe how compact the whole
thing was, with the built-in monitor, keyboard and cassette drive. And
it had a BASIC programming language that I liked. Yes, the Apple II also
had BASIC (only Integer basic at that time, I suppose) and one of the
main reasons I really felt at home with the PET is because the prompt it
gave was ?READY?, which was like the RSTS/E prompt ?Ready? which I was
familiar with. It sounds crazy, but that one little word gave me a warm
feeling about the PET and made it so that I could identify with
something I already knew. The Apple II ?>? prompt seemed very foreign to
me.

I spent many Saurdays down at NEECO talking with the others who came to
marvel at the PET. The owners of the store were very generous in
allowing us to congregate there, and chat about computers in general. I
guess it was sort-of like a computer club, but we never formalized it as
such.

May of 1978 came. My grandfather came one Saturday, and I planned to go
on our usual trip to NEECO. But, my grandfather opened the trunk, and
out came my 15th birthday present, an 8K PET 2001 of my very own.

One of the things I really liked about having a PET was that it was MY
computer. I didn?t have to listen to some privileged system manager tell
me what I could or couldn?t do. If I wanted to try something that might
crash or lock up the computer, that was just fine. I felt in control of
the system.

NEECO did very well selling the PET computer. I believe they were one of
the main sellers in New England, as they had a printed catalog which
they mailed out, showing the systems, and software they had for sale. I
don?t know for sure, but I think they did a fair amount of mail order
business. Some of the people who spent their Saturdays at NEECO started
writing software that went into the NEECO catalog, and the author would
get a commission on every copy sold. One such program I fondly remember
was Hal Wadleigh?s ?WAR GAMES? package, which had 4 games; one was an
anti-aircraft firing game, one was a depth charge game, and I don?t
remember the other two. These were interactive games which made good use
of the PET graphics and I was awed by how someone could write a program
in BASIC to make these games work.

My dad and I wrote a game we called ?Masterbrain?, which was basically
the game Mastermind. We put that in the catalog for sale. I wrote a
shooter game I called ?Star Wars?, where fighter ships would come into
your screen, and you?d have to align the gun onto them and fire. I was
only 15, and I was very na?ve about things like name copyrights and
trademarks. I probably made a couple hundred dollars total on
commissions for the Star Wars game, but for a 15-year old in 1978, that
seemed like an awful lot.

One of the guys who spent some time on Saturdays at NEECO was Ted Scott.
He was not only a good software developer, but he was also an electrical
engineer and knew a lot about the hardware side of things. He developed
a device for the PET which he called the ?Music Box?. It connected to
one of the external ports, and had a speaker, and special software. One
of the programs actually displayed music on a staff and played it on the
Music Box. It was only one note at a time (monophonic) but this was
quite a while before people starting using the ?CB2 line? (I think
that?s what it was called) for sounds. The main difference between the
Music Box and the later CB2 approach was that by poking a memory
location, you?d only get a ?Click? out of the speaker, and you had to
write timing loops to get different pitches. The CB2 approach used the
6522?s internal registers to determine what frequency to generate ? just
set the frequency, and turn it ?on?, and then back ?off? when you wanted
the sound to stop.

One of the things the PET allowed me to do was go beyond BASIC
programming. I started to learn about things like 6502 assembly
language, and direct screen writing by store data into ?screen memory?.
I did a little hacking with the Music Box to figure out what made it
work. I then started writing my own 6502 routines which made sound
effects from the speaker of the Music Box. I incorporated some of these
sound effects into a newer version of my ?Star Wars? game and advertised
it as supporting the Music Box for sound. As I recall, I don?t think I
ever asked Ted Scott for permission to do this ? I just did it. But, I
didn?t use any of his code ? just used the hardware if it was there ? so
I may have sold some Music Box units for him.

I wrote an awful lot of other programs for the PET. Many of them were
just tinkerings, but they helped teach me many concepts about
programming and computers. I got very interested in writing 6502
routines that could be called from a BASIC program, to do things faster
than BASIC could do. I didn?t have a 6502 assembler that I liked ? the
only one I had was tape based, and very cumbersome to use. So I learned
to hand-assemble 6502. At one point, I had a good portion of the
instruction set memorized. I could disassemble 6502 instructions in my
head, and have a good idea of what a routine might do just by looking at
the hex opcodes. One of the things the PET did not support was
?blinking? text on the screen, yet it had normal, and reverse letters.
One of my neatest routines I wrote (in my mind, anyway) was a routine
that would create blinking text. There was an area in memory where you?d
POKE in the start row/col and length of the text you wanted to blink,
then activate the routine, and it would cause that area to blink
steadily (?in the background?). The routine hooked itself into the video
interlace interrupt on the PET. You could change the flashing areas
simply by POKEing new values into memory.

One of the other programs that I wrote and sold through NEECO?s catalog
was a word game called ?PROBE?. The basic idea was that each player (the
human and the computer) would pick a word, and then try to guess the
other player?s word. I entered a whole bunch of words from the
dictionary for the computer to use, and also did some analysis on these
words to give the computer some smarts when making guesses. For example,
if the opponent had a ?T? showing with nothing before it, the computer
knew what the most likely letter to precede ?T? is, and it would guess
that. If that failed, it might try the second-most likely letter to
precede ?T?, or see what other letters the opponent had showing and try
to guess a letter before or after that. The logic worked quite well, and
many games were evenly matched.

One of the neatest things I recall is that Ted Scott took apart a Texas
Instrument ?Speak & Spell? game and created an interface between it and
the PET. He created some software that would access the Speak & Spell?s
vocabulary and the computer could cause it to talk. He loaned me this
modified Speak & Spell for a few days, and I modified my PROBE game to
speak the letters as they were guessed. Could this possibly have been
the first TALKING game?

My dad and I worked on a Backgammon game. We devised a routine for the
computer to make educated moves. I was the ?graphics guru? and my dad
was the logical thinker, so we worked well on this project together.
Unfortunately, the 8k PET memory didn?t give us enough space to refine
our backgammon playing strategy as much as we wanted. Fortunately, a
company called CompuThink was coming out with a memory expansion board
that you could mount inside the PET to expand the memory up to 32K.
NEECO ?loaned? (that?s what they said, but I often wonder if my
grandfather purchased it) us a 24k expansion board to refine our
Backgammon game. The CompuThink board also had 2 expansion ?slots?, and
they soon came out with a floppy disk drive that you could plug into the
board. This drive was out before Commodore?s floppy disk drive. I got a
CompuThink disk drive which made my life much easier. Many ended up
buying the Commodore disk drive, but I much preferred the CompuThink
dual drive system for the PET.

My dad got frustrated with not being able to get enough time for himself
on the PET, and ended up buying an Apple II for himself. At first, I
didn?t pay much attention to the Apple II, but over time I became
intrigued with it?s graphics, capability to run a modem (which I
couldn?t do with the PET), and a friend asked me to write some software
on the Apple II for him, so the PET started to get less use. NEECO moved
their store from Springfield to Needham, MA (near Boston) and our little
Saturday informal group more or less broke up.

I still have my PET, although I?m sure it is not operational. I did have
some power supply problems at one time, which Ted Scott fixed. It ran
fine for a while, but I believe the problems came back and that?s when I
finally stopped using the PET. It has probably developed other problems
that would keep it from running now also. I don?t think the CompuThink
memory board is installed anymore, but I probably still have it. I know
I still have the CompuThink disk drive. I can take some pictures of this
equipment if anyone is interested.

I?ve been able to restore some of my games that were saved to tape into
a current PET simulator program by playing the tapes into a PC
soundcard, and having a decoder program decode the sound on the tapes
and store it in disk files. Unfortunately, most of my later (and better)
PET work was saved on floppy disks. I believe I still have the disks,
but have no idea if they still contain data, or how to go about getting
them read into a PC.
The programs I know I have recovered are PROBE, STAR WARS, and some
version (I?m sure not the ?latest and greatest?) Backgammon.

   - Bob Lafleur
     Springfield, MA USA
Received on Sun May 12 2002 - 03:33:48 BST