On Sat, 2 May 2020 at 15:50:27, Paul wrote:
[]
And the Green Switch might be a Sleep button, but I can't
be sure of that. PCs have had more than two switches on the
front, but I don't know what that was for. They also had
Power LED, IDE LED, as well as Message LED, where Message LED
might have lit up when an email poll picks up new mail. I don't
think I've owned a PC with that on it :-)

Paul

I've never had (or even seen, I think!) a PC with a message LED.

Two buttons: well, going _really_ far back (I _think_ to AT rather than
ATX, but there _might_ have been overlap): the other one was usually
labelled "Turbo", and controlled processor speed. (Sometimes there was a
two-digit LED display showing the MHz; I don't think I ever saw one
where there really was a counter, I think the switch just switched
segments, as well as the processor speed!) Anyone who had such a PC
nearly always ran it at the faster speed, of course. I believe when
faster (!) PCs _first_ appeared, the switch was there to reduce the
processor clock to the original PC clock speed, so that any software
that actually expected that (there allegedly was some such software -
maybe clocks before they started putting a cheap watch chip on the
motherboard? I don't know [oh, hang on - I think it was also some games,
which ran too fast if the processor did]), but on most of the PCs I
encountered that _did_ have a "Turbo" switch, _both_ speeds available
were faster than the original PC clock speed. (Which I think was some
commonly-available crystal - NTSC colour subcarrier or something? 4.77
MHz rings a bell, though I thought NTSC colour was three point
something.)
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

'It works for me' is not the same as it isn't broke - Kenn Villegas, 2010-2-19
in
https://rwmj.wordpress.com/2010/02/1...egistry-sucks-
technically/