Stupid CP/M question

From: Dean Billing <drbilling_at_ucdavis.edu>
Date: Fri Jan 15 14:34:33 1999

At 08:03 PM 1/15/99 +1, you wrote:
> ...
>> The first hard disk was made by IBM around 1956, and I assume it didn't
>> take them much longer to write a DOS for it, but I don't know when they
>> did or what it was called.
>
>Didn't they already use the term DOS ?

The first commercially available IBM disk system was the IBM 305 RAMAC, but
I believe the disk was just a peripheral device like a tape drive, not a
system disk like we view it today. There certainly was no operating system
stored on the disk and I doubt they even stored a program on the disk. It
was pretty small electronically although it was physically huge, and
incredibly slow because it only had one read/write head that had to be moved
from disk platter to disk platter.

Since all IBM computers of the era, the 700's and 7000's were punch card fed
machines, the programs were stored on punched cards and loaded each time
they were to be run. Tape drives held intermediate results and input and
output data, but not programs. At some point the the 7000 series life I
believe there was a primitive "Tape Operating System", or TOS, developed so
that once a program was debugged, the compiled binary version could be
stored on tape, and a punch card "IPL" program could read that tape, load
the program and then the machine would continue on just as if it had read
the program from punched cards.

After the 305 RAMAC was designed, a disk drive that I believe was called the
2305 was developed and it was hooked to the 7000 series machines. At some
time around 1964 IBM coupled a 2305 to a 7044 which had a Direct Couple
interface to a 7094 and used the 7044 to stage and control program loading
on the 7094. A primitive "DOS" was developed called IBSYS, but all it did
was que programs and data on the disk to be run on the 7094, one program at
a time. This greatly minimized operator setup time and kept the very
expensive 7094 humming. I don't think it was until the delivery of the
S/360, in the 1968 time frame, that IBM had an operating system that they
called DOS, but maybe there is an IBM expert in the group that could comment.

-- db
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Received on Fri Jan 15 1999 - 14:34:33 GMT