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This article makes two important errors, unless I am much mistaken. [0] First: the ZX81 was not a "Timex Sinclair" product on the day of its launch because Tim

This article makes two important errors, unless I am much mistaken. [0] First: the ZX81 was not a "Timex Sinclair" product on the day of its launch because Timex didn't get a licence to manufacture it in the USA until the following year. Second: Sinclair Research was never (again, unless someone can correct me) a "Timex Corporation"! If it had been, it wouldn't have gone conclusively bust and been given a new life by Grumpy St Alan of Sugar, the brave champion of British national technology pride. "Timex Sinclair" was the US licensing venture (not the maker). Timex pulling out of that deal (because the Spectrum was understandably too British in spirit to easily flog to a market that had birthed the Apple II and where the C64 was cheaper) is arguably the start of Sinclair's slow-building battle against the tide. -- [0] Important in the sense that I, as a Brit of a certain age, must correct them in the interests of a kind of battered and timeworn national pride. I would put these corrections in comments on the original article, but that would mean having a Disqus account, and in my experience that ultimately means encounters with trolls.

helsinkiandrew 5y ago
Timex Sinclair was a joint venture to market the ZX81 in the US. I don't remember Timex ever being used in the UK at the time? https://en.wikipedia.org/wiki/Timex_Sinclair https://en.wikipedia.org/wiki/Timex_Sinclair
- unfocussed_mike 5y ago
  > I don't remember Timex ever being used in the UK at the time? No, indeed it wasn't -- perhaps my initial comment wasn't clear. (Some of that might be the latent British rage of the overlooked) I've amended a bit. (In fact I doubt the Timex Sinclair devices even worked here, and vice versa, hence the need for a manufacturing deal that dealt with needing NTSC and 60hz power etc.)
  - scoot 5y ago
    NTSC just needed a different modulator; and the ZX81 used a simple transformer/bridge rectifier/smoothing capacitor brick to convert to 9v DC, with a regulator in the computer to convert down to 5v, so 60Hz wouldn't have been an issue, although the mains power connector is obviously different. So, there's nothing special about a machine for the US market that required it to be manufactured there. Presumably it was commercially preferable to do so. You're correct though that a US model wouldn't work in the UK without modification, and vice versa.
shever73 5y ago
Absolutely correct. Thank you for typing it out in such an eloquent, yet curmudgeonly, fashion. It saved me from having to do it!
shever73 5y ago
Although, Timex (technically) was the manufacturer. The ZX Spectrum, at least, was built in the Timex factory in Dundee [0] [0] https://www.bbc.co.uk/news/business-29122873 https://www.bbc.co.uk/news/business-29122873
- unfocussed_mike 5y ago
  Yes -- though this was under contract, I guess. (Like how the Raspberry Pi is manufactured under contract by Sony in Wales)
  - shever73 5y ago
    Yes, exactly. The article is still very wrong.
- ZeroGravitas 5y ago
  And some trace the history of Grand Theft Auto and Lemmings back to this factory and the local boom in computers it produced, with one of the Rockstar North founders working in the Timex factory before creating his first game: https://www.nostalgianerd.com/from-dma-to-gta-the-story-of-dma-design/ https://www.nostalgianerd.com/from-dma-to-gta-the-story-of-d...
  - rwmj 5y ago
    Also - https://www.youtube.com/watch?v=RbAVNKdk9gA https://www.youtube.com/watch?v=RbAVNKdk9gA
krallja 5y ago
It also claims that “the Z80 CPU at 3.25 MHz was actually faster than the Apple II processor (1.08 MHz).” This is, pedantically, true, in that the oscillator is ringing faster. However, the 6502 completes more work per clock cycle than the Z80 does. A single-byte instruction (such as “increment the A register”) takes 2 clock cycles on 6502, 4 cycles on the Z80. More complicated instructions can take up to 7 cycles on the 6502 and 20+ on the Z80. The estimate I use is that a 6502 is approximately 3x faster clock-for-clock than a Z80. Also, the Apple II CPU didn’t spend 70% of its time drawing the screen! It had separate video hardware that transparently interleaved with the unused back half of the CPU clock cycle. The ZX81 was tricked into “executing” sequential screen-memory addresses in a very tight loop by falsifying its data bus with a NOP instruction. Fancier computers would use dedicated DMA hardware. Not Sinclair!
- unfocussed_mike 5y ago
  Right. They were really simplified, and up against US economies of scale that meant less simple machines could be made at competitive prices. I think Timex's main projection was that the Sinclair machines would be affordable over the long term. But I guess in the USA, the competition became cheaper much faster than they expected. Over in the UK, as well as more expensive imported Commodore machines, the native competition included the very expensive BBC Model B and its cousin the Acorn Electron, the beloved and excellent Dragon 32, the quite inexpensive Jupiter Ace (think ZX81/Spectrum but running FORTH natively!), and Tangerine's Oric-1, which was adorable, and as with the Amstrad CPC sold well in France, expanding its market size a bit. The Spectrum 48K did well against them on price-performance, though the Oric-1 was often cheaper and is arguably the better device. In the USA, much larger economies of scale meant that the C64 was more affordable, and for cheaper machines the Spectrum was up against the VIC-20 and Atari 400, and even Mattel wanted a chunk of the low-end in that same period of time with the Aquarius (which is similarly simple Z80 stuff).
  - krallja 5y ago
    BTW, the Jupiter Ace and ZX81 both have excellent iOS emulators, written by Kevin Palser.
zabzonk 5y ago
Timex did manufacture the ZX81 in the UK at their Dundee factory: https://www.thecourier.co.uk/fp/past-times/2030845/dundee-watchmakers-started-making-sinclair-computers-at-timex-in-1981/ https://www.thecourier.co.uk/fp/past-times/2030845/dundee-wa...

helsinkiandrew 5y ago

Timex Sinclair was a joint venture to market the ZX81 in the US. I don't remember Timex ever being used in the UK at the time? https://en.wikipedia.org/wiki/Timex_Sinclair https://en.wikipedia.org/wiki/Timex_Sinclair

unfocussed_mike 5y ago
> I don't remember Timex ever being used in the UK at the time? No, indeed it wasn't -- perhaps my initial comment wasn't clear. (Some of that might be the latent British rage of the overlooked) I've amended a bit. (In fact I doubt the Timex Sinclair devices even worked here, and vice versa, hence the need for a manufacturing deal that dealt with needing NTSC and 60hz power etc.)
- scoot 5y ago
  NTSC just needed a different modulator; and the ZX81 used a simple transformer/bridge rectifier/smoothing capacitor brick to convert to 9v DC, with a regulator in the computer to convert down to 5v, so 60Hz wouldn't have been an issue, although the mains power connector is obviously different. So, there's nothing special about a machine for the US market that required it to be manufactured there. Presumably it was commercially preferable to do so. You're correct though that a US model wouldn't work in the UK without modification, and vice versa.

shever73 5y ago

Absolutely correct. Thank you for typing it out in such an eloquent, yet curmudgeonly, fashion. It saved me from having to do it!

shever73 5y ago

Although, Timex (technically) was the manufacturer. The ZX Spectrum, at least, was built in the Timex factory in Dundee [0] [0] https://www.bbc.co.uk/news/business-29122873 https://www.bbc.co.uk/news/business-29122873

unfocussed_mike 5y ago
Yes -- though this was under contract, I guess. (Like how the Raspberry Pi is manufactured under contract by Sony in Wales)
- shever73 5y ago
  Yes, exactly. The article is still very wrong.
ZeroGravitas 5y ago
And some trace the history of Grand Theft Auto and Lemmings back to this factory and the local boom in computers it produced, with one of the Rockstar North founders working in the Timex factory before creating his first game: https://www.nostalgianerd.com/from-dma-to-gta-the-story-of-dma-design/ https://www.nostalgianerd.com/from-dma-to-gta-the-story-of-d...
- rwmj 5y ago
  Also - https://www.youtube.com/watch?v=RbAVNKdk9gA https://www.youtube.com/watch?v=RbAVNKdk9gA

krallja 5y ago

It also claims that “the Z80 CPU at 3.25 MHz was actually faster than the Apple II processor (1.08 MHz).” This is, pedantically, true, in that the oscillator is ringing faster. However, the 6502 completes more work per clock cycle than the Z80 does. A single-byte instruction (such as “increment the A register”) takes 2 clock cycles on 6502, 4 cycles on the Z80. More complicated instructions can take up to 7 cycles on the 6502 and 20+ on the Z80. The estimate I use is that a 6502 is approximately 3x faster clock-for-clock than a Z80. Also, the Apple II CPU didn’t spend 70% of its time drawing the screen! It had separate video hardware that transparently interleaved with the unused back half of the CPU clock cycle. The ZX81 was tricked into “executing” sequential screen-memory addresses in a very tight loop by falsifying its data bus with a NOP instruction. Fancier computers would use dedicated DMA hardware. Not Sinclair!

unfocussed_mike 5y ago
Right. They were really simplified, and up against US economies of scale that meant less simple machines could be made at competitive prices. I think Timex's main projection was that the Sinclair machines would be affordable over the long term. But I guess in the USA, the competition became cheaper much faster than they expected. Over in the UK, as well as more expensive imported Commodore machines, the native competition included the very expensive BBC Model B and its cousin the Acorn Electron, the beloved and excellent Dragon 32, the quite inexpensive Jupiter Ace (think ZX81/Spectrum but running FORTH natively!), and Tangerine's Oric-1, which was adorable, and as with the Amstrad CPC sold well in France, expanding its market size a bit. The Spectrum 48K did well against them on price-performance, though the Oric-1 was often cheaper and is arguably the better device. In the USA, much larger economies of scale meant that the C64 was more affordable, and for cheaper machines the Spectrum was up against the VIC-20 and Atari 400, and even Mattel wanted a chunk of the low-end in that same period of time with the Aquarius (which is similarly simple Z80 stuff).
- krallja 5y ago
  BTW, the Jupiter Ace and ZX81 both have excellent iOS emulators, written by Kevin Palser.

zabzonk 5y ago

Timex did manufacture the ZX81 in the UK at their Dundee factory: https://www.thecourier.co.uk/fp/past-times/2030845/dundee-watchmakers-started-making-sinclair-computers-at-timex-in-1981/ https://www.thecourier.co.uk/fp/past-times/2030845/dundee-wa...