8 Bit Computers

Radioshack/Tandy TRS-80 Model 1 - 1977

The TRS-80 (or Trash-80 as it was also known) was released in 1977 and was a very early 8 bit micro. It was very well built and aimed at business users. At an initial price of nearly £400, there were few others who could afford one! TRS stands for Tandy Radio Shack. Radio Shack were an immense US company in those days and they were persuaded that computers were the next in-thing. For the year, the specification was not bad. A proper keyboard, an unusual 64x16 display and its own black and white display. It was this display that was the reason for the high price. Incidentally, that funny screen size is understandable if you knew how screen memory was arranged. Most machines in those days set aside 1KB (1024 bytes) for the screen memory. 25 lines of 40 characters equals 1000 bytes. 16 lines of 64 bytes just happens to equal 1024.

The remainder of the computer was as expected for the time. Memory was either 4 or 16KB but expandable internally to 48KB. There was only a 4KB Level-1 ROM which provided a stripped down version of BASIC including being limited to integers as were many other computers of the time. It offered a "graphics" mode though this was limited to a second set of characters which were split into a 4 x 4 matrix with characters for every option of black and white for that matrix e.g.

By displaying the right characters in the correct order then pictures would appear in much the same way they use in Teletext which uses the same method.

A Level-2 ROM followed which was 12KB and offered floating point numbers plus many other additions making the TRS-80 a very competent though expensive computer. I remember seeing these in Tandy stores when I was younger though had never actually seen one in proper use.