Re: David Caminer (1915-2008)
- From: wdonzelli@xxxxxxxxx (William Donzelli)
- Date: 30 Jun 2008 13:00:04 -0700
No, the writer is quite technically astute and meant that the vacuum
tube circuits with their chokes, coils, etc. were ELECTRICALLY noisy.
But knowing that their audience wouldn't have a clue (as the editor
didn't either) and so cut all that out so that it just said that the
vacuum tubes were noisy (since the editor's only exposure to vacuum
tubes are at their bank's drive-in).
</extreme sarcasm>
Noticing the sarcasm, but...
Tubes used in computer applications can indeed be noisy, but that is
not the issue. The noise can be tolerated quite easily in those high
voltage digital circuits. In fact, most computer tubes of the 1940s
and 50s were more or less standard radio types, maybe souped up a
little in some areas, but were tested using less stringent noise
tests. Likewise, computer tubes often were tested with less stringent
tests concerning balance of sections and hum. These qualities, like
noise, just did not matter in a mainframe logic module.
Noise was more of an issue with the early semiconductors. They were
really rather poor performers, especially the British types, so noise
started to become a big issue. The low voltage everything operated at
in the transistor machines meant that external and internal
interference could result in garbage on the signal lines that could
get uncomfortably close to logic thresholds - flipped bits.
The article basically gets it wrong.
--
Will, wanting a 709
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