Re: The Design of Design

Tim Rentsch wrote:

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

 

snip

 

The biggest fault of JCL is that it
is trying to solve the wrong problem.

 
What problem was it trying to solve and what was the "right"
problem?

 
The problem it was trying to solve is contained in its name:  Job
Control Language.  It tacitly accepted the non-interactive batch
model for what it needed to address.

You may be right, but correct me if I am wrong, there was no
non-interactive model in the mid 1960s when JCL was devised.  They
didn't address it because they couldn't forcast (obviouslyincorrectly),
that it would be a problem to solve.

The problem that was in need of addressing is interactive use.  I
think there are two reasons why JCL was so poor at that.  One is
that they knew that teleprocessing would be important, but they
tried to cram it into the batch processing model, rather than
understanding a more interactive work style.  The second reason is
that the culture at IBM, at least at that time, never understood the
idea that using computers can be (and should be) easy and fun.  The
B in IBM is Business, and Business isn't supposed to be fun.  And I
think that's part of why JCL was not viewed (at IBM) as a failure,
because their Business customers didn't mind.  Needless to say, I am
speculating, but for what it's worth those are my speculations.

Fair enough.  A couple of comments.  By the time TSO/360 came out,in
IIRC the early 1970s, they were already committed to JCL.  TSO ran as a
batch job on top of the OS, and handled swapping, etc.itself within the
region allocated to TSO within the OS.  It was a disaster.  Of course
this was later addressed by unifying TSO into the OS, but that couldn't
happen until the S/370s (except the 155 and 165) and virtual memory.
But the legacy of two control languages was already set by then.

As for "fun". I agree that IBM didn't think of computers as fun, but
there were plenty of reasons to support interactive terminals for
purely business reasons, a major one being programmer productivity in
developing business applications.





--
 - Stephen Fuld
(e-mail address disguised to prevent spam)