phipps@fortune.UUCP (Clay Phipps) (04/28/84)
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The long-awaited-but-cancelled IBM Future Systems (FS) line of mainframes
supposedly incorporated the concept of "single-level store", essentially
what the original posting described. It reportedly used 64 bits of address.
It was to be a "capability machine".
I am personally convinced that the "Mass Storage System" ("Son of Data Cell")
was designed for FS, but later grafted onto the S/370 line when FS was canned.
MSS takes the place of tape archives, using a LRU algorithm (flawed in MVS)
to select files to migrate to MSS, and demand-restoring absent disk files
to disk when they are referenced.
The IBM System/38 implemented many of the rumored FS concepts.
It has a "single level store" that uses a 48-bit address,
which gave every one of the 281 trillion bytes of data on the system,
regardless of where it was stored, a unique address.
The addressing scheme uses hash tables to avoid having the 1 billion bytes
of resident page tables that the S/38 would conventionally require
for addressing. I doubt that this scheme is very speedy, however.
One description of this is in
Merle E. Houdek and Glen R. Mitchell (both of IBM GSD):
"Hash Index Helps Manage Large Virtual Memory",
*Electronics*, March 15 1979, p. 111 ..113.
IBM also published a collection of papers under a name something like
"System/38 Technical Description" during the same time period.
I believe that the British (English Electric ? ICL ? U of Manchester ?) Atlas
had a "single level store", and was (if my memory serves) the first computer
with paged virtual memory, back around 1960. The file and memory system
was fairly simple, with paging used primarily to avoid memory fragmentation,
so I'm not sure that it matches your description.
It's described in the 1st edition of Bell & Newell [which I don't have
available right now, naturally].
Of course Burroughs has probably done work in this area, too.
I believe that they had logically independently segmented memory
before anyone else.
-- Clay Phipps
--
{cbosgd decvax!decwrl!amd70 harpo hplabs!hpda ihnp4 sri-unix ucbvax!amd70}
!fortune!phippskoved@umcp-cs.UUCP (04/28/84)
A description of the IBM System/38 can be found in the second edition
of the Bell & Newell book. There are 3 articles on the system and
its architecture. I have tried to get a copy of a series of articles
about the System/38 (published roughly 1978, IBM Publication S580-0237),
but it appears to be an obsolete publication, and may be out of print.
Does anyone have a copy?
I have talked with one of the original engineers of the System/38, and
he tells me that it works, and the customers love it (so much for the
propoganda). For those people who don't know what a System/38 is, it
is a medium sized business machine (it seems such a waste....it could
do so much more!!). It uses message passing for device independent
communication, and hardware descriptors for addressing and capabilities.
--
Spoken: Larry Koved
Arpa: koved.umcp-cs@CSNet-relay
Uucp:...{allegra,seismo}!umcp-cs!koveddyer@wivax.UUCP (Stephen Dyer) (04/30/84)
Yeah, when I heard that S/38's biggest programming language was RPG-II, I began to wonder whether all this fancy underlying architecture was worth the trouble. -- /Steve Dyer decvax!bbncca!sdyer sdyer@bbncca
lincoln@eosp1.UUCP (Dick Lincoln) (04/30/84)
> Yeah, when I heard that S/38's biggest programming language was > RPG-II, I began to wonder whether all this fancy underlying > architecture was worth the trouble. By now they're all using RPG-III, and you should take a look before you knock it. RPG-III bears almost no resemblance to the original IBM "rippage" that was so correctly ridiculed. You can do just about everything in RPG-III that you can in C. COBOL has also long been a supported System-38 product, although I'm no fan of "cobolty-wobbilty". Although IBM wouldn'T tell anyone this, the *real* reason for the fancy "capabilities" System 38 architecture was for IBM, so they could afford to develop tons of software for the 38 in a protective and properly diagnostic environment. Compared with its competition, it really does have a mass of direct vendor-supplied software that works. It's also one of the few systems you really can learn without manuals (self programming aside) once you learn how to log on and get the first Help menu.