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Craig Sawyers · 18th May 2017, 7:02 pm

The Uncle Clive effect. Back in the day, Sinclair negotiated hundreds of kilos of reject transistors from manufacturers. The staff at Sinclair would test them to find the few percent that worked well enough to go into a product (tiny radio, amplifier etc). Rumour has it that the vast majority of really defective transistors were used as hard core under Sinclair's drive.

At one stage I had a Sinclair Scientific calculator. You could ask it to find the arcsine of an argument greater than +/-1. The LED display would start to flash randomly and intermittently for several minutes - after which a result would appear! Of course such an answer exists - it is a complex number. The Sinclair Scientific knew nothing about complex numbers, however ;-)

I can't remember whether it was the ZX81 or the Spectrum that a mate bought new. He stuck in a programme which included the square root of two. The result was very close to being close, but had an error. He changed it so that it was finding the root of (2.0001) and got a much much closer answer.

Basically to save computing time, they had put commonly used constants into RAM. But they had entered root2 incorrectly! So any programme that used root2 had an error. However if you put in something that was not quite 2, it used an algorithm to calculate it.

18th May 2017, 7:02 pm	#4
Craig Sawyers Dekatron Join Date: Nov 2010 Location: Oxford, UK. Posts: 4,976	Re: Sinclair ZX81 The Uncle Clive effect. Back in the day, Sinclair negotiated hundreds of kilos of reject transistors from manufacturers. The staff at Sinclair would test them to find the few percent that worked well enough to go into a product (tiny radio, amplifier etc). Rumour has it that the vast majority of really defective transistors were used as hard core under Sinclair's drive. At one stage I had a Sinclair Scientific calculator. You could ask it to find the arcsine of an argument greater than +/-1. The LED display would start to flash randomly and intermittently for several minutes - after which a result would appear! Of course such an answer exists - it is a complex number. The Sinclair Scientific knew nothing about complex numbers, however ;-) I can't remember whether it was the ZX81 or the Spectrum that a mate bought new. He stuck in a programme which included the square root of two. The result was very close to being close, but had an error. He changed it so that it was finding the root of (2.0001) and got a much much closer answer. Basically to save computing time, they had put commonly used constants into RAM. But they had entered root2 incorrectly! So any programme that used root2 had an error. However if you put in something that was not quite 2, it used an algorithm to calculate it.