Retro Computer Memories: TRS-80 Model 100

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TRS-80 Model 100 is one of my favorite computers from my vintage computers collection.

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Although build in 1983 it’s in so cute and compact form that you immediately fall in love when you look at it.

This is the mother of all Notebooks and Laptops 🙂 with of only 1.4 KG with the batteries (4xAA 1.5V type) and size of only 300x215x50mm.

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It was designed by Kyocera under the name Kyotronic 85, this model was so well designed for it’s time that Tandy, Olivetti and NEC decided to license the design instead to make their own.

More than 6 Million units were sold just by Tandy in US and Canada.

The processor inside TRS-80 Model 100 is 80C85 running at 2.4 Mhz. The RAM memory is humble 8K expandable up to 24K by slots inside and at the back of the computer.

The LCD display is 240×64 pixels 8 lines x 40 characters, there is build-in 300 bps modem, parallel printer port, RS232, bar-code reader, cassete input, RTC, external CRT connector.

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The firmware is inside of 32KB ROM and contain Microsoft BASIC interpreter with good support for all hardware.

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here is our Hello World program written in Basic:

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What is remarkable with this firmware is that the Model 100 firmware was the last Microsoft product that Bill Gates developed personally, along with the Japanese hardware developers.
According to Gates, “part of my nostalgia about this machine is this was the last machine where I wrote a very high percentage of the code in the product”.

When introduced, the portability and simplicity of the Model 100 made it attractive to journalists,who could type about 11 pages of text and then transmit it using the built-in modem for electronic editing and production. The batteries allow up to 20 hours of work without connection to external power supply.

The Model 100 was also used in industrial applications as a programming terminal for configuration of control systems and instruments.

This is how main board looks inside:

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and this is the LCD and keyboard board which is connected to the main board with ribbon cable:

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This 30 years old machine is so well build, that works fine even today, all it need is 4 x AA batteries!