Iron History: 40 years ago, the TRS-80 personal computer went on sale

On August 3, 1977, Tandy Corporation, together with Radio Shack, released one of the first personal computers in the world - TRS-80. Partners, of course, wanted to succeed in selling their products. But both companies did not even imagine that this computer would not only become popular, but would go down in history. The management that managed this project set a maximum sales plan of 1,000 units per month, not too hoping for its implementation.

Reality exceeded all expectations. Once the six hundred dollar TRS-80hit the shelves, they began to disassemble it, like hot cakes. It can be said that it was this model that led to the emergence of computer enthusiasts in the United States and other countries “from the people,” and not from academic organizations. A new era has begun, in which computers play a major role.

TRS-80 itself was not bad, although work with it was complicated by the need to perform many operations to solve relatively simple tasks. But this did not stop anyone. In the first month, the number of sales of this PC model was ten times higher than expected. It became clear that ordinary people are already ready to use a fairly complex technique.

Of course, this model was not the first personal computer to go on sale. Prior to this, the MITS Altair microcomputer was introduced.. First published by Popular Electronics in 1975. Then IBM and Apple began to produce their own versions of personal computers. But only the TRS-80 can be called one of the first computer systems, which, immediately after being installed on the user's desk, was ready for use. It is fully assembled, it did not need to be modified, adding any nodes and elements, there was no need to solder anything.

This computer did not have a hard drive, and it could also boast of four kilobytes of RAM. But it was a fully-fledged computer. Not so many applications were released for him, but there were already some specialized programs and even games. Some time after the release, this system was called Model I. The kit included a cassette recorder that allowed you to write data to tape and then read them.

The motherboard and computer keyboard were combined in one case. The processor here worked at a frequency of 1.77 MHz, the system used Zilog Z80. Later models were delivered already with Z80A processors. Also, after some time, the developers increased the amount of RAM - from 4 KB to 16 KB.



The video controller of the system supported a quite good text mode for that time with 16 lines of 64 or 32 characters per line. The resolution was 128 * 48 pixels. Video memory was installed separately, its volume was 1024 * 7 bits. In this case, the lower 6 bits determined the code of the ASCII character, or they were displayed directly in the form of a grid of 2 * 3 blocks. In subsequent models, including the TRS-80 Color Computer , a “semi-graphic mode” was added, where low-resolution graphics were emulated using special characters.

Included except Radio Shack CTR-41, included a black and white CRT monitor, which was a slightly modified RCA XL-100 TV. His screen glowed in a light blue color, which weary eyes. For this reason, some users installed green or yellow color filters on the display, or simply replaced a whole picture tube. Realizing the problem, the developers began to produce a monitor with a green glow.

All user data due to the presence of a cassette recorder was recorded on a compact tape. The computer, namely its tape interface, was sensitive to changes in the recording level of the signal. It was difficult to understand that the recording was going on correctly, so users recorded their data several times on different tapes, quite reasonably believing that one of the recorded copies of the data would be read later.