Vijay Kumar wrote:
I have searched the net and not able to find which of the Jes version was
introduced first JES2 or JES3. I know Jes2 was evolved after HASP and Jes3
was after ASP.
Could anyone please let me know the specific dates or year in which these
two job entry subsystems were introduced.
DCS (Direct Coupled Systems) came in 1962. ASP came in 1966. HASP came
in 1967. JES came in 1972. JES2 and JES3 came in 1973.
Here is an excerpt from SHARE Session 2738 "JES3 40th Birthday Party"
(commemorating the 40th anniversary of ASP for OS/360), held last year
in both Seattle and Baltimore. These notes were provided by Wayne Rhoten
of IBM. Download the presentation if you want all of the details, dates,
etc.
http://shareew.prod.web.sba.com/client_files/callpapers/attach/SHARE_in_Baltimore/S2738PK170053.pdf
JES:
The third major version of spooling was in OS/VS1 (ed. after ASP and
HASP). It came out about a year before OS/VS2 came out. VS1 was derived
from the MFT configuration of OS/360. MFT and VS1 supported a fixed
number of tasks and job partitions. Endicott created a completely new
kind of spooling around JES, job entry subsystem. It was not called JES1
because there was no other JES but later some people referred to it as
JES1. It was Endicott's response to the success of HASP and ASP although
it was completely new code written in an earlier version of PL/X.
For VS1 JES, a new form of QSAM and BSAM was created. It was called JES
CI, which meant JES compatibility interface because it converted the DCB
requests to ACB requests. This is when VSAM was being designed and
everyone thought that soon all I/O would be done with ACBs and RPLs. JES
used ACBs and RPLs for all I/O. When JES read the job input stream from
a card reader, disk or tape or wrote sysout data sets to printers,
punches or tape, it used an ACB and RPL. JES CI was renamed to SAM SI,
sequential access method subsystem interface and it was adapted to use
the new SSI, subsystem interface, with the IEFSSREQ macro that is common
between JES2 and JES3. SSI and IEFSSREQ were new in MVS. SVS did not
have them.
Another component was used to do the reverse mapping. It was called RCI,
reverse compatibility interface. In this case JES opened an ACB, which
was handled by RCI, which used QSAM under the covers to do the real I/O
to read and write unit record, tape and disk devices. According to my
memory, a remarkable fact about RCI is that no APAR ever was received. I
understand that RCI was not copied to MVS.
OS/VS2 version of HASP and ASP:
OS/VS2 was derived from OS/360 MVT. When Poughkeepise put the first
release of VS2 out, they chose not to copy JES. They chose to use HASP
and ASP doing the same thing they did in OS/360. There was no JES CI or RCI.
JES2 and JES3:
I think the first releases of VS2 were 1.0, 1.6, 1.7 and 1.8. The
release after
that was a major enhancement (2.0) and deserved a new name, OS/VS2 MVS,
Multiple Virtual Storage, and the previous releases were retroactively
renamed
to OS/VS2 SVS, Single Virtual Storage.
Much to the irritation of purists, the system people renamed HASP and ASP to
JES2 and JES3, although they shared no code with the original JES. They
resisted and retained "HASP" in module names and message numbers.
JES CI was copied from VS1 with only a few changes. One such change was
a new concept called the subsystem interface, SSI. Another change was to
rename it to SAM SI, sequential access method subsystem interface. JES2
and JES3 each became a subsystem and SAM SI (emulating QSAM or BSAM)
called the subsystem.
--
Edward E Jaffe
Phoenix Software International, Inc
5200 W Century Blvd, Suite 800
Los Angeles, CA 90045
310-338-0400 x318
[EMAIL PROTECTED]
http://www.phoenixsoftware.com/
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