TRS-80 the "Trash-80"
|The Model III TRS-80
At the end of 1979, there were over a million personal computers operating in the United States. In fact, it was possible that over a million TRS-80s alone were sold. Radio Shack has never released the figures. One result of this was a marked increase in television interference in homes. A computer in operation generates AC interference at radio frequencies. This can be broadcast through the air, or transmitted through the power lines.
It is the job of the FCC to regulate electronic equipment to see that these emissions do not interfere with communications. They have a massive job to do, and by 1978, a large number of complaints were being received. The FCC published regulations covering personal computers and expected the manufacturers to comply. Most of the computers at that time were housed in metal cabinets which shielded them and made it easy to comply with the FCC regulations. Two computers were housed in plastic cabinets and they could not meet the FCC Regulations. These were the Apple II and the TRS-80 Model I. Apple managed to gain approval by coating the inside of the cabinet with a metallic finish and shielding the cable openings.
Radio Shack, however, could not make the TRS-80 Model I meet FCC regulations because of the separate units and the cable connections between them. As a result, they accomplished a complete redesign of the TRS-80 into a completely self-enclosed desk top cabinet. This was called the TRS-80 Model III. First ready in July 1980, in its cassette version it sold for $699 and incorporated many features that had been included in the Expansion Interface. The Model III had a 12-inch screen, which displayed the standard 96-character ASCII set with both upper and lower case characters. It also displayed 64 graphics characters and 160 special TRS-80 characters. The keyboard provided for entry of all the standard characters, including upper and lower case. There was also a 12-key numeric keypad. The Model III used the Z-80 CPU and from 16K to 48K of RAM. A parallel printer port was provided. Data storage was provided by either cassette or an optional floppy disk controller, and up to two internally mounted floppy disk drives. Additionally, two external floppy disk drives could be connected into the system. There was an option for installation of an RS-232C port for connection to a modem.
Model III BASIC and MODEL III TRSDOS were improved over Model I, but care was taken to make Mode III software compatible with Model I. If this proved impossible, conversion programs were often provided.
The TRS-80 Model III was one of the most successful computers ever built. It was used in schools throughout the United States, replacing the failing Commodores. It was used in offices, factories, and homes. By 1983, when it was replaced by the Model 4, a couple of million must have been sold. (Radio Shack has never given out the figures.) It was supported by the largest software libraries in existence up to that time, and several other operating systems were written for it. It became the standard grade school computer in thousands of school districts and the mainstay of small business.
TRS-80 Model 4
The TRS-80 Model 4 was the best of the mark and included many improvements that should have been made to the Model III during its years of manufacture. The Model 4 was probably the best 8-bit, Z-80 computer ever built. Unfortunately it came out too late, and had to compete with the IBM PC/XT and the onslaught of the clones. It remained in the catalog for a long time as a replacement for Model III's in schools and offices where they did not wish to lose their investment in software.
The most striking thing about the Model 4 was its white color. Charles Tandy had selected the metallic silver and gray colors, and after he died nobody in the company wanted to change it. To the outside world it looked old-fashioned and brought to mind the "Trash-80" image that competitors had tagged the TRS-80 with. Finally, they caught up with the times and made the necessary changes.
For the first time, the TRS-80 had an 80-column by 24-line screen, with an option to display high resolution graphics. The memory was expanded to 64K with an option to increase it to 128K. The disk drives were double density (184K,) and the keyboard was a full function with three programmable function keys. The operating system for the Model 4 was TRSDOS 6, which had been developed from LDOS, one of the independent operating systems. In addition, for the first time, standard CP/M was available for use on The TRS-80. Microsoft BASIC 2.0 was provided as the main language.
The Model 4 was designed to be compatible with the Model III. However, when operating with Model III software, the video display was 64-characters by 16-lines and the 48K memory restriction applied. The Z-80, which operated at 4 MHz as a Model 4, only ran at 2 MHz in Model III mode.
Radio Shack also introduced a portable version of the Model 4 called the Model 4P. This had a 9-inch CRT and two disk drives in a portable case.
An Evaluation of the TRS-80 Computers.
The TRS-80 family of computers has never received the credit they deserved as a cornerstone of the personal computer era. Mainly this is the fault of the Tandy Corporation, who failed to understand the importance of public relations in the development of a booming industry. While more TRS-80 computers were built and sold than any other kind, all the attention went to Apple, IBM, and even the small CP/M based machines, which never came close to TRS-80 in popularity and customer satisfaction.
Perhaps much of this was due to Tandy/Radio Shack's position as both manufacturer and retailer. They did not have to fight for shelf space in stores and woo the value-addled resellers. In addition, much of the TRS-80 sales went to schools and small businesses in the hinterlands of the U.S.A.
Not many major corporations were willing to trust their data processing to a "Trash-80" built by Radio Shack, no matter how good the technical people said it was. It was only when IBM made personal computers "respectable" did the data processing departments admit that there might be some value in these little computers.
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