The Big Three: 30 Years of Mass-Produced Home Computers
By James Grahame
It has been thirty years since the first wave of mass-produced home computers ignited a revolution. 1977 saw the introduction of the so-called "Big Three": The Apple ][, Tandy/Radio Shack TRS-80 Model I and the Commodore PET 2000. These machines dominated the North American market for several years.
I was still a kid when these machines were released, but I spent considerable time with each system in the early 1980s. Sadly, I never warmed to my dad's Apple; it seemed a tad clinical and "professional" for my taste. We had a couple of PETs at school, but my first love was a clunky TRS-80. I bought one with my paper route money and spent many hours with Dancing Demon and writing games in BASIC. And then I discovered girls and forgot how to count.
Tandy Radio Shack TRS-80 Model I: The Zilog Z80-based TRS-80 Model I was shipped as a ready to use $599 system. This little system took Tandy completely by surprise by significantly outselling sales projections, in part because of Radio Shack's extensive sales network throughout North America. The main board was built into the keyboard unit and shipped with a plug-in B&W monitor and portable cassette recorder for storage.
The base unit could support up to 16K of memory, although an expansion dock (shown above) was available that increased memory to 48K and controlled two floppy drives. I loved the crisp 64 character x 16 line display, although there were no lower case characters in ROM. The cassette-based storage was somewhat finicky, because you had to be careful to set the volume just right to ensure a successful program load.
Radio Shack introduced a number of popular machines throughout the 1980s, but they eventually found it impossible to compete with a tide of inexpensive IBM-PC clones. The TRS-80 name is now ancient history and Radio Shack now markets a "me too" lineup of name-brand PCs and notebooks.
Apple ][: This $1298 workhorse was based upon the low-cost 6502 processor and could support a then-incredible 48K of RAM and dual 5 1/4 floppy drives. It incorporated a good BASIC language interpreter and bit-addressable color graphics.
Perhaps most important from a hardware perspective, the system featured a backplane system that made it possible to attach a diverse range of peripherals such as the Mountain Computer sound card. The machine became surprisingly popular in business circles thanks to VisiCalc, the world's first spreadsheet program. The Apple II lineup remained in production until October, 1993 because of its dominance in the educational market.
Commodore PET 2001: The PET was also based upon the MOS 6502 processor. Unlike the Apple, the unique self-contained cabinet included a built-in tape deck for program storage, along with a 9-inch monochrome monitor and an absolutely flat keyboard that seemed to have been stolen from a supermarket checkout.
The standard PET didn't include bit-addressable graphics, but a range of somewhat useful icons were included in the character ROM. Later versions included a far better keyboard and eliminated the tape drive in favor of a standalone floppy drive.
Commodore went on to introduce a diverse range of 8-bit computers for the home market, including the VIC-20, Commodore 64 and the incredibly versatile Amiga series.