In
<caarmm9qzhn7172t7zvtkpapp+qqkbdhzjxaaoyq5cztm_aj...@mail.gmail.com>,
on 06/18/2012
at 05:56 PM, Tony Harminc <t...@harminc.net> said:
>I don't know CICS, but HASP also used few of the available OS
>services. Here's an excerpt from a little 1970-ish course handbook
>(SR23-3697-0) that explains why, with some not so gentle jabs at the
>performance of the OS services. I'm sure many of the CICS reasons
>were similar:
Some of the alleged reasons are bogus, and the excerpt leaves out an
important legitimate reason ;-)
> The primary use of main storage in HASP is for buffering space for
>input/output purposes. These input/output purposes require that an
>Input/Output Block be associated with each segment of main storage
No.
>In a similar fashion the Direct-Access Device Space Manager (DADSM)
>provides flexible and comprehensive services for normal job
>processing requirements but fails to meet the requirements of HASP
>in the following areas:
The excerpt doesn't mention the DADSM overhead; HASP can allocate
space in SPOOL much more quickly, even if the DADSM modules are
resident.
>Since the unit-record Input/output units which the scheduler
>allocates to the jobs being processed in other partitions must be
>available for use by HASP, HASP must be responsible for the
>allocation of its own input/output units.
No. The scheduler would not normally allocate unit record equipment to
a user job except for PCP, and when it does, every other job must keep
its hands off of it. Without HASP, unit record equipment is normally
allocated to reader and writer tasks, not to user jobs.
--
Shmuel (Seymour J.) Metz, SysProg and JOAT
Atid/2 <http://patriot.net/~shmuel>
We don't care. We don't have to care, we're Congress.
(S877: The Shut up and Eat Your spam act of 2003)
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