Friday, August 03, 2012

The TRS-80

35 years ago Radio Shack announced the TRS-80 Microcomputer. I ordered one two weeks later and finally got delivery just before Christmas.

1977 was an important year in computer history. Microcomputers are the parent of today's desktop computer. They had been around for a few years but mainly as kits. For $1,000-2,000 you got a case, one or more printed circuit boards, and a lot of parts. It was up to you to solder the right parts into the circuit board. Once you were finished you could expect to spend hours looking for places where some extra solder shorted out a circuit or you accidentally fried a transistor with your soldering iron (I'm repeating this from published how-to guides from the period). 1977 saw a new generation of microcomputers that were cheaper and were pre-assembled. This included the Commodore PET computer and the Apple II.

None of these had a fraction of the power of a smart phone. They were slow and had limited resources. Storage was limited to a cassette tape drive. Still, they were the first computers aimed at people who wanted a computer instead of an electronics project.

Radio Shack was trying to reinvent itself. A craze for CB radios had just ended and they were trying to improve their image. The TRS-80 was one of a line of new prestige products that were not expected to sell very well. Projections were that each store might sell one or two per year. Instead they sold their entire planned annual production the first day.

By the time that the TRS-80 was released I had a job and enough money (barely) to buy one. I went with the TRS-80 because it had a local dealer and because I could get an RF converter and hook it to a regular TV instead of paying $200 to them for a modified black and white set. I never regretted the choice. The Commodore had a non-standard keyboard and heat problems. The Apple was a nice computer for the time but the TRS-80 cost me $400 and an Apple was over $1,000.

The TRS-80 was cheaply produced. The expensive kits had multiple slots for memory and device drivers. The TRS-80 had a single motherboard. It looked like a thick keyboard. It came with 4k of ran and 4k of ROM which held its BASIC interpreter. The display was 16 lines of 64 characters. It also had a graphics mode made up of little white rectangles. Tandy saved money by only using 7 memory chips instead of 8 so it could only display upper case. It used the Z80 chip which could run at 4 megahertz but Tandy saved money by using an internal signal instead of adding a clock chip. This reduced its speed to around 1.77 megahertz. By any measure it was thousands of times slower than anything made today.

Within months Radio Shack announced upgrades. You could upgrade the 4k of ROM in your base unit to 16k, you could upgrade the 4k Integer BASIC to a 12k floating-point version from Microsoft and you could buy an expansion module. This plugged into the back of the original unit and allowed you to add another 32k of memory, a printer, and up to four disk drives. Suddenly the TRS-80 was a real computer able to compete with ones that cost thousands of dollars.

Radio Shack later renamed the original computer the Model I and introduced a Model II. This was a one-piece computer, monitor, and dual disk drives. Other models followed including one that eventually ran a version of Unix. By the early 1980s, microcomputers were competing with game consoles and were expected to have color and accept game cartridges. Radio Shack came out with three models of Color Computer for this market. The third one of these used the 6809 chip and could run an operating system known as OS-9 that was years ahead of anything that IBM or Apple offered.

By the mid-1980s Radio Shack had converted most of their lineup to IBM PC compatibles. By the late 1980s they decide that they could not keep up with the development costs and dropped their line of computers. Instead they began carrying ones from Compaq (now HP).

Commodore followed up their PET computer with the VIC-20 and the Commodore 64. Both were huge sellers.

Apple lucked out when the first "killer application", Visicalc was written for it. This was the first spread-sheet program and made the Apple II a must-have for business.

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