
Qui-binary arithmetic: how a 1960s IBM mainframe does math - JoachimS
http://www.righto.com/2015/10/qui-binary-arithmetic-how-1960s-ibm.html?m=1
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russell
I have fond memories of the 1401, although I never programmed one. In the mid
60s I worked for the Harvard Computer Center. We had a 1401 whose sole job was
a tape to print server for the 7094. It had attached a 1403 printer, a
screaming behemoth (literally) that could print 600 lines per minute.
[http://www.columbia.edu/cu/computinghistory/1403.html](http://www.columbia.edu/cu/computinghistory/1403.html)
compares the sound of a 1403 to a jet plane, an old jet, mind you, now one of
those whisper quite modern ones. There are stories of people writing music to
be played on a 1403, maybe even true. Another feature was the 1301 disk drive,
the size of two refrigerators, with an astounding 28 megabytes of
storage,whirling away at 1800 rpm. For a mere $2000 a month you could have
your own.

Computers tha one person can carry are for wimps.

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Perixoog
1403 music -
[http://wayback.archive.org/web/20070203125146/http://www.com...](http://wayback.archive.org/web/20070203125146/http://www.computerhistory.org/exhibits/highlights/)

~~~
omnibrain
I expected the link to be this:
[https://www.youtube.com/watch?v=_o_WF7N73Kw](https://www.youtube.com/watch?v=_o_WF7N73Kw)

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NelsonMinar
Shirriff has written several posts about the IBM 1401: his notes on SMS logic
cards are particuarly interesting. Sort of like a services architecture, only
instead of "real time database" as a component it's "three-way OR".
[http://www.righto.com/2015/03/a-database-of-sms-cards-
techno...](http://www.righto.com/2015/03/a-database-of-sms-cards-
technology.html)

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theoh
See also, for example, "what makes the 1401 so interesting?"
[http://www.zyvra.org/lafarr/ibm1401.htm](http://www.zyvra.org/lafarr/ibm1401.htm)

It's a shame there's no way to gather HN posts about the 1401 with a tag
"ibm1401".

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rdc12
Quite neat to be able to see, the logic on the board instead of being hidden
inside mass blob of transistors.

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tempodox
Shouldn't it rather be “bi-quinary” instead of “qui-binary”?

~~~
kens
As the first footnote explains, bi-quinary numbers are what an abacus uses:
one part is 0,1,2,3 or 4 and the other is 0 or 5. Qui-binary numbers are the
opposite: one part is 0,2,4,6 or 8 and the other part is 0 or 1.

