Re: Continuations

Stephen Fuld <SFuld@alumni.cmu.edu.invalid> schrieb:

Regarding EDIT, etc., I think there are three possibilities:
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1. They were a bad idea from the start and never should have been put
into S/360.

Probably not, given the environment at the time.

2. Putting them into S/360 was the right decision at the time, but the
changing technology (i.e. they wouldn't fit into the initial CISC
microprocessors and RISC showed the functionality could be done other
ways) made putting them into newer designs a bad idea.
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3. Putting them into S/360 was the right decision at the time but the
workloads changed. There was less requirement for things like actually
printing checks and general ledger reports, and programmers moved away
from COBOL, which was where EDIT was a natural fit, to languages where
there wasn't as natural fit, so not putting EDIT into newer CPUs was
the right decision.

I think it mostly has to do with the decimal machines that IBM sold
previously, and that the /360 should do everything that the old
machines could do.  (They messed up with floating point, which
was much worse than for the 704ff, as previously discussed).

Plus, microcode was cheapter these days than the hideously expensive
main storage (less work for reading, because the cards for microcode
didn't have a destructive read, and no magnetic cores with wiring).

If you wanted to read a punched card into a decimal number which
is encoded on a punched card and read in as EBCDIC, or print out
a decimal number, you didn't want to spend many instructions in
precious core memory on that task.

Tasks changed, memory became cheaper and bigger, and decimal
arithmetic was not so important any more.

I suspect it was mostly number 3, but I think number 2 was a part of it.

So, basically I agree.

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