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1401, 1410 Successors
A Blog

- Snyder to 1401 Restoration Team, February 6, 2008 at 12:02:22 PM
- Worthington to Snyder, February 6, 2008 at 3:33:03 PM
- SMD to Gardner & Cheponis, February 6, 2008 at 7:29:52 PM
- Cheponis to Snyder, February 6, 2008 at 2:05:45 PM
- Gardner to Cheponis, February 6, 2008 at 6:59:17 PM

From: Van Snyder
Subject: [1401_team] 1410 successor?
Date: February 6, 2008 at 12:02:22 PM PST
To: 1401 Restoration Team <>
I heard a story that a successor to the 1410, to be called 1480, was in the works at one time. I understand that it evolved into the 360/25, which was (so I am told) substantially different from other members of the 360 line.

Any truth to this story?

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From: Bill Worthington
Subject: Re: [1401_team] 1410 successor?
Date: February 6, 2008 at 3:33:03 PM PST
To: Van.Snyder
Cc: 1401 Restoration Team <>
The successor to the 1410 was the 7010. The former was announced in 1960 and the latter in 1962. It increased the main memory and added a few features but was really a performance enhancement to the 1410.

I believe that the 1480 was planned to be a successor and was then scrapped because the S/360 family was too close to announcement. S/360 was announced on April , 1964 (-- or was it March 38, 1964 since I heard a rumor it was supposed to be a first quarter announcement? :-D )

I suspect the 360/25 discussion is really meant to be about the 360/20. The former was a true member of the S/360 family and was announced in `968. Its memory maxed out at 48K and it had fewer channels than the 360/30. We had OS/360 PCP running on one in the Boston Datacenter back in the early 1970s -- even though it was not officially not a supported processor.

The 360/20 was not a full-function member of the S/360 family. It was the entry machine for what became the General System Division within IBM. It had a Multi-Function Card Machine (affectionately known as the M-F Card Mangler) which had two input stackers and five output selectable stackers. You could punch into cards from either input. You could also merge the two inputs into a single stacker if you were verrrry careful.


From: SMD
Subject: RE: [1401_team] 1410 successor?
Date: February 6, 2008 at 7:29:52 PM PST
To: 'Van Gardnerí, 'Mike Cheponis'
I had the "pleasure" of working for a while on a 360/20. I don't know that it was suited for anything. It was frustrating working with it because everything you knew about the 360 and expected it to work the same way didnít. A charmless machine. They should have just released the 1470 instead.

From: Mike Cheponis
Subject: Re: [1401_team] 1410 successor?
Date: February 6, 2008 at 2:05:45 PM PST
To: Van Snyder
I have also heard similar stories, and I'd also really like to know The Rest of The Story...
Thanks! -Mike

From: Van Gardner
Subject: Re: [1401_team] 1410 successor?
Date: February 6, 2008 at 6:59:17 PM PST
To: Mike Cheponis
The 360/20 was the model that was so different from the rest. The cheapest model was the 360/20 with as little as 4K of core memory, eight 16-bit registers instead of the sixteen 32-bit registers of "real" 360's, and an instruction set that was a subset of that used by the rest of the range. The Model 20 was suited to smaller businesses.
The Model 25 can operate as an IBM 1401, 1440, or 1460. It also can process a full range of System/360 Model 30 jobs, both scientific and commercial - - and users can convert to larger System/360s without reprogramming. There is a good picture and write up at:
Emerson Pugh's book "Building IBM Shaping an Industry and Its Technology" on page 273-274 tells of a 1401 system built out of SLT cards. The proposed product, tentatively designated the IBM 1470, was scheduled for announcement in February 1964. The development of a 1401 emulator with no software portion that ran on the 360/30 killed all the 1401 architecture projects. I could not find any mention of a 1480 in any of Pugh's three books.
Van Gardner