[geeks] Oldest OS Still Developed

Wed Oct 18 16:38:38 CDT 2006

On Wed, Oct 18, 2006 at 09:58:42PM +0100, Mike Meredith wrote:

> Well some of the early 360s had a hardware(?) emulator for the 1401
> (from 1959). I have a distant memory (so very suspect) of that being
> replaced with a software emulator, so it is feasible that 1401 code can
> still be run on a modern IBM mainframe ?

The first 360 the 360/30 was a microcoded machine. There was a 1401 emulator
that could be loaded that took over the computer and ran as a 1401.

There were several models in the 1401 series. I've seen a 1401, 1410 and 1460.

You had to IPL (the IBM term for boot) a 1401 operating system.

I once had to fix a 1401 autocoder (the name for assembly language in those
days) program that ran under the IBM 1401 emulator on a 370/168 running MVS.

Geoff.

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