44-bit 370 virtual addressing

Gideon Yuval

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Feb 21, 1988, 1:32:43 PM2/21/88

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IBM has just announced their 44-bit-virtual-address extension to the 370
architecture (known as ESA/370, short for Extended Storage Architecture).

Anyone got hard facts on what the ESA/370 architecture looks like?

--
Gideon Yuval, +972-52-522255 (work), -2-690992 (home), yu...@taux02.nsc.com

Stan Lackey

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Feb 22, 1988, 11:26:56 AM2/22/88

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In article <4...@taux01.UUCP> yu...@taux01.UUCP (Gideon Yuval) writes:
>IBM has just announced their 44-bit-virtual-address extension to the 370
>architecture (known as ESA/370, short for Extended Storage Architecture).
>Anyone got hard facts on what the ESA/370 architecture looks like?

This information was presented at the Supercomputer Conference last year.
The talk was to present the Vector Facility, but there was lots of
background information on the Extended Architecture given as well.

The 44-bit addressing applies to the Expanded Storage, a RAM-based paging
"device" behind the Central Storage unit (i.e., main memory). Physical
addressing in Central Storage is 2**31 bytes, while Expanded Storage is
architecturally defined as 2**31 PAGES (page size is 4K bytes). Expanded
Storage uses ports supplied in addition to the channels, and it was claimed
that paging between Central Storage and Expanded Storage averages over
60 MBytes/sec.

This accounts for 44 bits of physical addressing. If there is really 44 bits
of virtual addressing, it was beyond that that was presented.

-Stan Lackey

Henry Spencer

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Feb 22, 1988, 7:43:39 PM2/22/88

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> Anyone got hard facts on what the ESA/370 architecture looks like?

Long odds it looks a lot like an 8086. Barf.
--
Those who do not understand Unix are | Henry Spencer @ U of Toronto Zoology
condemned to reinvent it, poorly. | {allegra,ihnp4,decvax,utai}!utzoo!henry

grun...@uiucdcsm.cs.uiuc.edu

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Feb 23, 1988, 10:59:00 PM2/23/88

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Oh my, it would appear that IBM has discovered 'ECS' -- Extended Core Storage,
which has been used on Cyber systems for a number of years.

I used to work on the PLATO system, which ran on antiquated Cybers 73's at
the time. They had 2MW of ECS which they used for swapping (you didn't get
rolled to disk, ever) and when that wasn't enough they built AMS (Aux. Mass
Storage) which could go up to 4 or 8MW.

I don't know if NOS used ECS for roll-outs or not, since we never really used
NOS very much.

Rostyk Lewyckyj

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Feb 24, 1988, 11:11:49 AM2/24/88

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In answer to

> > Anyone got hard facts on what the ESA/370 architecture looks like?

he...@utzoo.uucp (Henry Spencer) writes:
>
> Long odds it looks a lot like an 8086. Barf.
> --

I would appreciate it if Mr. Spencer would expound more fully
on the details of the ESA extensions, and point out the similarities
with the (Intel?) 8086.

My only information so far is from reading the IBM customer announce
ment letters of February 16, and some comments on what was presented
at the Supercomputer Conference last summer.

-----------------------------------------------
Reply-To: Rostyslaw Jarema Lewyckyj
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