On Thu, 12 Jul 2007 15:09:47 -0500, McKown, John wrote:
>
>> I thought one of the reasons why IBM came up with AVGREC and the
>> other new SMS allocation parameters was to get rid of the idea of
>> tracks and cylinders concept. I went on the band wagon years ago to
>> change over. I was totally unsuccessful. People (I think) are
>> used to
>> doing it the old way and do not want to change.
>> Ed
>
>Same here! Their reason: "I understand what a track and a cylinder is!"
>Like they didn't understand allocation by number of records for some
>reason. Or in MiB or GiB. Nope, gotta be in tracks or cylinders because
>they understand how big that is. HUH???
>
Yes. However the JCL designers, of whom my opinion is well
known in this group and much reinforced by the convoluted syntax
of space allocation parameters, appear to have gone out of their
way to make it incomprehensible. I'd like to be able to allocate
a 27GB file by:
SPACE=(1,27000000000),AVBLK=3120
(my allocation unit is 1 byte, and I need 27G of them). AVBLK
is meaningful because it informs allocation how much to allow
for interblock gaps. But AVBLK=0 should be accepted as an
indication that I wish to trust SDB. Or, even:
SPACE=(1,27G),AVBLK=3120
But what must I do instead? And why? Is it because the JCL
parser uses only halfword arithmetic and can't deal with
numbers larger than 32767? This is a royal pain when trying
to generate JCL from a program and needing to generate the
not-quite-base-1024-floating-point that the notation seems
to be. And why is the keyword denoting the multiplier the
utterly counterintuitive "AVGREC"?
Decades ago, I attended a presentation by an IBM salesman for
a new online service for ISVs for electronic delivery of
products and service packages. The entry level package allowed
one megabyte of online storage (sic; imagine!). One of
my colleagues quickly asked, "What would that be in tracks or
cylinders?" I hope (I don't recall) the salesdroid answered
by asking that it depends on how big the tracks or cylinders
are on the device under consideration.
-- gil
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