If those tape drives were on a 7090, they were probably 729's. They went
on 7080's, 7090's, and 7094's mostly. Some 1610's IIRC.
Long time ago. First machine I fixed as an FE. Equitable Life in NYC.
1973 I think.
Doug Fuerst
------ Original Message ------
From "Phil Smith III" <[email protected]>
To [email protected]
Date 11/7/2025 16:31:55 PM
Subject Re: Ancient history: 3420s
Ah, sorry, I meant to say: it was a physical label on the tape. Kinda an important detail I
omitted! So it wasn't "security" per se, more like the Luhn on a credit card, to avoid
entry error (in this case, "grab error").
-----Original Message-----
From: IBM Mainframe Discussion List <[email protected]> On Behalf Of
Paul Gilmartin
Sent: Friday, November 7, 2025 4:28 PM
To: [email protected]
Subject: Re: Ancient history: 3420s
On Fri, 7 Nov 2025 14:42:59 -0500, Phil Smith III wrote:
Lots of unlabeled tapes, especially on VM.
This was a backup for that.
How was that "4-character hash " communicated to the operator?
On 11/7/2025 9:52 AM, Phil Smith III wrote:
The 3420 reminds me: back at UofW, they had a system that would create a
4-character hash (I assume) from the tape number. So when you asked for tape
1234, the operator would pull it and when they responded to the mount request,
they had to enter that 4-character value. If they'd accidentally pulled 1235
instead, there would be a mismatch and it would tell them to try again.
--
gil
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