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WalterBright 3 days ago

> The negative responses from clients were instant.

Back when I was designing TTL circuits, the TTL specifications gave a min and max time for the delay between the inputs and the outputs. I was instructed to never rely on the min delay, as the chips kept getting faster and the older, slower replacement parts will not be available anymore.

The IBM PC was frustrating to many hardware engineers, as too much software relied on timing loops and delays in the original design, which made it difficult to make the hardware go faster.

WalterBright 3 days ago | parent | next [-]

On older cars, like my '72 Dodge, the system voltage varied between 12 and 18 volts. But the dash instruments needed 5 volts. This was achieved with a clever "buzzer" circuit using an electromagnet and contacts. The circuit would open when it was above 5 volts and close when it was below. This created 5V, but was a noisy 5V.

Many people decided to improve this with a semiconductor voltage regulator, which would nail the output at 5V. But the instruments wouldn't work! The problem turned out to be the instruments relied on the noisy 5V to "unstick" the needles on the instruments.

So the electronics guys had to add a "noise" circuit to the voltage regulator circuit.

P.S. Watch an old aviation movie, where the pilot getting ready to fly would tap the instruments to unstick them.

mike_hearn 3 days ago | parent | prev [-]

Ah, the Turbo Button!

I think by the time I got my first IBM PC the button no longer did anything, but it was still there on the case for some reason. I remember pushing it repeatedly, puzzled that nothing went faster.

WalterBright 2 days ago | parent [-]

I have one in my car. It doesn't do anything, either.