jim@fritz.UUCP (Jim Gilbert) (12/12/85)
Burroughs "large" mainframes are a segmented architecture. Compilers on these
systems map COBOL SECTIONs, and designated collections of Algol
procedures to segments. Their Algol compilers automatically
segment arrays out via dope vectors. Programs using single
data objects through multiple applications views, e.g.
a FORTRAN program which EQUIVALENCEs a 5000x1 array atop a 20x250 one
begin to need to worry about the segmentation. Most others
do not. I am not aware of a compiler for C on these systems.
They do support COBOL, FORTRAN, Pascal, Algol, PL/I, and BASIC.
There is, unfortunately, no popular desktop implementation of this
architecture.
For what it is worth I believe that the architectural limit on the
number of bytes in a single procedure in the Burroughs Large Systems
architecture is 8192 bytes.
I am not aware of an 64K limit on individual segments however.
These magnificent machines have been much overlooked. Elliot
Organick wrote a pleasantly instructive book about them.
They run Algol like the wind. It would not be much of an exaggeration
to say that they ARE Algol in hardware.
In 1961 the ancestor of these machines supported symmetric multiprocessing,
segmented virtual memory, and an all high level language operating system.
A shame it took so many of these ideas so long to catch on.
I now wait to see what interesting flames this draws. How many of
you folks have an "I Touched a B-5000" button? How many of you even
know what the book named "The Descriptor" is, let alone have read it?
Whomever answers, "Who cares?" chooses to ignore a fair amount of
interesting architectural pioneering.
Technology advances have changed many of the economic tradeoffs around
which these systems were designed. I, for one, believe that anyone
who wishes to speak on the pro's and con's of segmented architectures
should do their homework on computing history. Microprocessors were
not invented at the beginning of time.
Jim Gilbert
FileNet Corporation
ihnp4!trwrb!felix!jimgrr@unirot.UUCP (George Robbins) (12/15/85)
In article <4338@fritz.UUCP> jim@fritz.UUCP (Jim Gilbert) writes: > >Burroughs "large" mainframes are a segmented architecture [lots of details and praise] >I am not aware of a compiler for C on these systems. >They do support COBOL, FORTRAN, Pascal, Algol, PL/I, and BASIC. Is there a 'real' C compiler for big Burroughs machines out there? > >There is, unfortunately, no popular desktop implementation of this >architecture. > The HP3000 series architecture is essentially a 16/32 bit implementiation of the Burroughs B5500 architecture. HP's operating systems implementation language seems to be based on ESPOL. I know there were some Burroughs type hackers working for HP, but would really like to hear a little of the story behind this... > [more praises] >Technology advances have changed many of the economic tradeoffs around >which these systems were designed. I, for one, believe that anyone >who wishes to speak on the pro's and con's of segmented architectures >should do their homework on computing history. Microprocessors were >not invented at the beginning of time. > > Jim Gilbert FileNet Corporation > Well, I cut my teeth on a B5500, found out about real languages with ALGOL, and learned about OS's and virtual memory from the MCP, unfortunately, a RISC architecture with some supporting software can do the same tricks for much less money. The microcoded machine concepts used in the B1600-1700 machines are more interesting. I think a *fast* chip level implementation might prove to be a possible general solution to the Pascal/Forth engine problems. -- George Robbins uucp: {unirot|tapa}!grr P.O. Box 177 Lincoln U, PA 19352 [Any ideas herein are not responsible for themselves!]