Documentary - The Sinclair ZX80, ZX81, and Timex Sinclair 1000
The 8-Bit Guy・2 minutes read
In the late 1970s and early 1980s, personal computers like the ZX-80 and ZX81 by Sinclair Research aimed to provide affordable options in the emerging computer market, offering basic capabilities and limited storage options. These early models featured minimal design, low resolution screens, and were priced competitively to expand the reach of computing technology to a broader audience, despite their limitations and lack of advanced features.
Insights
- The Sinclair ZX-80, priced at 79 pounds, was a pioneering attempt at an extremely affordable personal computer, featuring minimal design and limited capabilities like a 32x24 character display and cassette storage.
- The ZX81, an upgrade to the ZX80, offered improved functionality with a larger ROM, enhanced BASIC capabilities, floating-point math, and primitive graphics, all at a lower price point of 49 pounds in the UK and under a hundred dollars in the USA, showcasing advancements in cost-effective computing solutions.
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Recent questions
What were some early personal computer options in 1980?
Apple II, TRS-80, Commodore PET, Texas Instruments TI99/4, Atari 400.
What was the price of the Sinclair ZX-80?
79 pounds for a DIY kit or $140 pre-assembled.
What were the key features of the Sinclair ZX-80?
Z-80 microprocessor, 1K RAM, 4K ROM chip, minimal design.
How did the ZX81 differ from the ZX80?
Cheaper, larger ROM, improved BASIC, primitive graphics.
What challenges did the Timex Sinclair 1500 face?
Market failure due to strong competition.
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Summary
00:00
Early affordable personal computers: Sinclair ZX-80
- In 1980, personal computers like Apple II, TRS-80, and Commodore PET were available but still expensive.
- More affordable options like Texas Instruments TI99/4 and Atari 400 emerged in 1979, costing around $550.
- Sinclair ZX-80, designed by Science of Cambridge (later Sinclair Research), aimed to be extremely cheap.
- The ZX-80 was priced at 79 pounds for a DIY kit or around $140 for a pre-assembled unit.
- The ZX-80 featured minimal external design, with only a video output port and power and tape recorder jacks.
- Internally, the ZX-80 had a Z-80 microprocessor, 1K RAM, and a 4K ROM chip for BASIC and I/O routines.
- The ZX-80 lacked audio capabilities and used a shift register for video output, limiting it to 8 pixels at a time.
- The ZX-80's screen could only display 32x24 characters, using most of its 1K RAM for screen memory.
- Programs exceeding 256 bytes intruded into screen memory, causing the screen to shrink from the bottom up.
- The ZX-80 stored programs via cassette recorder, lacking other storage options or game cartridges due to cost-saving measures.
11:49
Evolution of Z80-based microcomputers: ZX80 to ZX81
- Both boards use the Z80 processor, with the new system having an 8K ROM compared to the 4K ROM of the other board.
- A custom chip called ULA consolidates various logic chips in the new system, reducing costs.
- The ZX81 was sold for 49 pounds in the UK and under a hundred dollars in the USA, making it cheaper than the ZX80.
- The ZX81 has a larger ROM and significant changes to BASIC, now capable of floating-point math and primitive graphics.
- SLOW mode in the ZX81 allows multitasking, enabling video generation while executing program code.
- Sinclair offered an upgrade path for ZX80 owners to switch to the ZX81, costing about 20% of buying a new ZX81.
- Timex marketed the Timex Sinclair 1000 in the USA, featuring 2K of RAM and a unique master chip replacing multiple chips.
- The Timex Sinclair 1500, a later version, had 16K of RAM and a better keyboard, but faced market failure due to strong competition.
