Introducing The Friendly Computer!

When Commodore introduced the VIC-20 they called it The Friendly Computer.  This is probably more because of the manual they included with it than because of anything else.  The book was really easy to understand.

Here is my own VIC-20.  This is an early one, with the squared off keys and the two-prong power plug.  I've got it plugged into a Sylvania TV using an RF modulator.

If you look closely at the screen it reports CBM BASIC V2, and 3583 BYTES FREE.  The computer comes with 5K RAM, but it uses some of that to map the screen, and some more for managing the BASIC interpreter.  If they had thought to provide 8K RAM this would have doubled the amount the programmer has access to.  This would have made the VIC-20 a lot more powerful.

Nowadays people wonder how anything could every be written with only 3.5K RAM, but we were so used to this back then.  You might be surprised how much can be done with a little ingenuity.  As a comparison, the original Atari 2600 VCS game console had only 128 bytes of RAM.  The VIC-20 has 28 times more RAM!  In addition, you could plug a RAM expansion cartridge into the VIC-20 to add more RAM.  Commodore made several sizes up to 16K RAM, and other companies made bigger ones.

I also have a Commodore C2N cassette drive.  I also had one of these in the 80's.  I have been using the tape drive to save some small programs.  This is nothing like a floppy drive, but you can save programs by name, and it sure beats retyping in programs every time you want to use them.

I also have a Commodore 1571 floppy drive.  These are great, but they don't make it possible to send and received programs to and from other people on the Internet because the disks have a format that can't be read on Macs or PCs.  I want to share what I'm doing, so I have purchased a kit to build my own SD flash memory adapter that will behave like a floppy drive and also let me use the SD card to copy files to other computers so I can share with others.  I'm very excited about that and I'll blog about it also.

Trouble with the Floppies

In my first years of computing my experience with floppy drives was pretty good. I had used several computers for thousands of hours total, and had seen hardly a hiccup reading and writing floppy disks.

The computers I had experience with floppies included:

Apple II+
IBM PC
Heathkit H-89

These used brands like Shugart and Tandem for their floppy drives.

Working with Patrick Alessi there was little trouble. He did smoke a pipe constantly around the equipment but this didn't seem to cause any problems.

At C.F.C. it seemed like floppy disks were more temperamental. Not that they weren't reliable enough for day to day use but they would cause problems just enough to be annoying. Maybe it was the industrial environment, or maybe the quality level for drives and floppy disks was falling. I dunno. Some of our disks came from customers and were formatted by their computers, so maybe that also had something to do with it. Floppy disks had become cheap and didn't have the same quality they did a couple of years earlier.

Some floppy drives could be calibrated using software and a screwdriver. I did try some of that, but I can't say I remember it being very successful.

The Osborne 1

The Osborne 1 was a portable CP/M computer with a Z-80 processor. It looked like a portable sewing machine. You tip it on its side and undo the latches and the end would come off revealing a keyboard which was attached to the rest of the machine by a wide ribbon cable. Removing the keyboard revealed two large floppy drives, a tiny 5 inch screen, cubbies for floppy disks, and a bunch of ports. We would plug the RS-232 cable from the paper punch into one of the ports.

The 5 inch screen could only display 52 characters wide, but it could scroll. You had to have a tolerance for reading very small type to use this machine. I was okay with it, but today I probably wouldn't enjoy it.

Aside from editing CNC programs, we also had MBASIC on these machines and so we could do a little programming to help us with our work. Bob knew how to write in BASIC and he had written a few things. For example there was a program for spitting out a simple routing program for a rectangular board. You just punch in the size of the board and it would generate a file. Anything more complex than that required manual coding.

One problem we had with the Osborne 1 machines we had was that the keyboard bezel was metal and it wasn't grounded well. If you walked up to the computer and touched the keyboard it wasn't unusual to discharge some static electricity and reset the computer, losing whatever work you were doing.

Floppy disks

In the early micro days we used cassette tapes and floppy disks. Floppies were better for many reasons but they were expensive. The Apple Disk II drives were $495 including the controller. Once you had one of these babies you still needed floppy disks. I remember pretty clearly in the early 80's spending $80 for a box of 10 floppy disks. These were Dysan disks, and were of very good quality.

However these disks probably exceeded the quality required. Later on some less expensive floppy disks became available from the likes of Maxell and memorably named Elephant Memory Systems. These were $2.50 or so per disk. The disk surfaces weren't as polished, and some cheap brands didn't have a reinforced mount but no matter really. The cheap disks were pretty much as reliable as far as anybody could tell.

Disk drive systems themselves were all quite different from each other. Apple's legendary Steve Wozniak had managed to create the ultimate in economy of design for a disk controller with a small card having only 5 ICs. Most other disk controllers were long circuitboards with 2 to 3 dozen chips. Monsters. ;-)

Some of these floppy drives used hard sector disks, meaning that there was an index hole in the media for each sector on the disk. So, if the disk was meant for a 16 sector drive, the disk would have 16 timing holes cut out of it evenly around the inner part of the disk. This would be read by an LED and a sensor. The Apple II used soft sector disks where there was only one hole cut in the disk, and the drive controller itself decided how many sectors to put on the disk by doing careful timing.

I remember that my father's H-89 had hard sector disks. The drives also made a strange clunking noise as they operated. The Apple II's drives made the much more familiar brrrr, brrr, mmm, mmm sound of most floppy drives and they were faster than the H-89 drives.

Applesoft BASIC

So settling down to programming on the Apple II+, we had several books to help me with the process. Of course there was the standard green covered Applesoft book, and Mr. Alessi also has another book but I can't remember the title. I tried to find a shot of the book cover on Google but no luck.

Before we started writing inventory management software I tried my hand at creating some graphics. The Apple II had hi-res graphics (for that day), and Applesoft had high level commands for drawing so you didn't need to POKE and PEEK as much as in other BASICs. We had only a green phosphor monitor without color, but this was appropriate for business software development.

When editing a program in Applesoft BASIC, you could type some escape sequences to move the cursor around. If you moved the cursor up to the start of a line on the screen you could then reenter the line by moving the cursor to the right, and you could substitute some characters to change the line of code. This was crude compared to the way you did things on a VIC-20 where you just moved the cursor to the line you wanted to edit, changed just what was needed and hit Return.

Also, I had never written software before that used a floppy disk. This was another thing that I needed to become comfortable with. Our Apple II had 3 floppy drives, each was 143K. We also had a 16K card and a Z80 Softcard so the machine could run CP/M, but this was something we rarely did.