RE: MVT COBOL under MVS3.8j.

Thanks for the nomenclature clarification Tony. Not sure where I'd heard the
term "bulk core". In any case, we never had a 2361, but I used to read
everything I could get my hands on, so I'd at least read about it !
 
Shelby
 


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From: [email protected] [mailto:[email protected]] 
Sent: Friday, September 13, 2019 9:53 AM
To: [email protected]
Subject: Re: [H390-MVS] MVT COBOL under MVS3.8j.


  

On Thu, 12 Sep 2019 at 04:13, Giuseppe Vitillaro giuseppe-yuD/ahkh7LvrZ44/[email protected]
wrote:

> REGION=(nnnnnxK[,nnnnnyK])

Shelby provided the answer. But just for historical interest (if such
exists here), the term was LCS (Large-Capacity Storage, though I've
also heard Large-scale Core Storage). This was a separate stand-alone
box, model 2361, with anywhere from 1MB to 8MB of core, addressable
exactly like normal storage, but running much slower.

We had one of these as late as 1975, and the box had glass windows on
two sides of a corner, through which you could actually see the very
large (and therefore slow) cores easily with the naked eye, so this
was always a feature on machine-room tours, along with whirling tape
drives. They looked like small washers strung on wires. The 2361
connected to certain models (IIRC /50, /65, /75, and maybe the rarer
/85 and /195). The connection was by pairs of channel cables, though I
don't think the channel was involved in any way; the cables and
connectors were just nice familiar technology for IBM to repurpose.

BTW, the cycle time for LCS was 8 uS! And I just found a fuzzy picture
of the 2361 with the windows in the System/360 System Summary on
bitsavers.

There was another JCL keyword (strictly speaking, a subparameter of
the DCB= keyword) that refers to LCS: HIARCHY= {0 | 1} on the DD
statement. (Note the strange spelling to make hierarchy fit into 8
chars. Maybe it also aligns conveniently with the way some Americans
pronounce hierarchy...) This was to tell the xSAM access methods where
to allocate buffers from.

Tony H.