Weekly Classic Computer Trivia Question (20141205)

Michael Holley swtpc6800 at comcast.net
Sat Dec 6 21:13:43 CST 2014

Several early IBM computers used decimal addressing; the IBM 1401 at the
Computer History Museum in Mountain View CA is an example. I think is has
16,000 locations.  If BCD addressing had won out there would not be a
problem with disk vs RAM capacity.

-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Noel
Sent: Saturday, December 06, 2014 6:55 PM
To: cctalk at classiccmp.org
Cc: jnc at mercury.lcs.mit.edu
Subject: Re: Weekly Classic Computer Trivia Question (20141205)
Main memory has pretty much _always_ been sold in blocks that were exact
powers of two, for obvious reasons (at least, powers of two of the word size
of the machine in question)...

(Although occasionally, back when, one used to see things that were 1.5
times a power of two, e.g. on a 16-bit machine, 12KB, 96KB, etc - physical
and cost constraints tended to produce those. I don't recall the last time I
saw something that wasn't a power of two - probably those 96KB jobs.)

With disk drives, on the other hand, one can get all sorts of arbitrary
sizes, produced by the number of cylinders, numbers of heads, etc, etc.


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