| Re: binary, was Why the Soviet computer failed [message #416679] |
Wed, 14 September 2022 21:40  |
John Levine
Messages: 1405
Registered: December 2011
Karma: 0
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Senior Member |
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According to Andreas Kohlbach <ank@spamfence.net>:
> On Wed, 14 Sep 2022 17:57:06 -0000 (UTC), John Levine wrote:
>>
>> People were certainly aware of binary arithmetic but it took a
>> surprisingly long time to realize that the benefits of doing
>> everything in binary outweighed the cost of converting to and from
>> decimal for I/O. ...
> Wasn't one of the main reasons an unreliable voltage? So if you had bad
> (cheap) electronic parts, but expect them to produce either 0 or 5 V,
> some might produce 4, and other time it should have 0 but for some reason
> produces .8.
No. The circuits were all digital, even in the ENIAC 1-out-of-10
decimal, and digits were constructed out of bits on various ways. The
question was whether the programmer saw digits or bits.
There were analog computers too, that used continuously varying
voltages to represent values, but they disappeared in the 1960s as
digital circuits started to run at frequencies vastly higher than
anything an analog system could do.
--
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly
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| Re: binary, was Why the Soviet computer failed [message #416680 is a reply to message #416679] |
Wed, 14 September 2022 22:06  |
ERSHC
Messages: 12
Registered: May 2013
Karma: 0
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Junior Member |
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On Thu, 15 Sep 2022 01:40:42 -0000 (UTC), John Levine <johnl@taugh.com> wrote:
> There were analog computers too, that used continuously varying
> voltages to represent values, but they disappeared in the 1960s as
> digital circuits started to run at frequencies vastly higher than
> anything an analog system could do.
>
And they are coming back as sub-systems, in part because they are much
faster and more efficient at some things that AI cares about. Two
op-amps and some other bits will solve second order ODEs faster than a
digital system will, and consume a lot less energy in the
process. Matrix times vector stuff involving real numbers happens in
"real time". No need to wait for CPU cycles, just for the current (or
voltage) to get to the end of the wire. Cool stuff!
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