IBM 5120 at the local thrift store

From: Eric Smith <eric_at_brouhaha.com>
Date: Wed Oct 14 16:45:12 1998

I wrote:
> Does IBM reuse model numbers? I suppose they must, or four-digit numbers
> would have been exhausted long ago.

Doug replied:
> Are you suggesting that IBM has produced over 10,000 different computer
> models? I doubt it!

The IBM numbers are 'Type' numbers. For instance, for the Type 729 tape
drives, there are Model I, II, III, etc. For the Type 360 computer, there
were initially Models 30, 40, etc. The IBM AT was Type 5170, but had many
Models, such as the famous 339.

However, for computers, each box generally had its own Type number. When
you talk about an IBM Type 7090 Data Processing System, that's actually just
the type of the main processor. The memory, the I/O channels, even the
control console each have their own type number, from the same name space.
Even a 360/30 has a Type number for its CPU, although I don't recall offhand
what it was.

They've definitely had more than 10,000 Types, and probably more than 100,000
Models. But not every Type is a "computer".
Received on Wed Oct 14 1998 - 16:45:12 BST