Hi, I think the question "Which is better JES2 or JES3?" is one for the bigots, and is akin to "Which is better z/OS, z/VM or z/VSE?"
Many of the more senior members of the list will know that the two Job Entry Systems existed prior to MVS but were developed independently for different purposes. JES2 being developed from the Houston Automatic Spooling System (HASP), and JES3 was begat from ASP. As I understood it at the time HASP was classified as a Field Developed Product being created by IBM employees outside of the product cycle, whereas ASP was a bona fide development. (1969 was a long time ago so I now have Virtual Memory, in that I remember virtually everything.) One of the design constraints for ASP was to assist Attached Processor Support and aid scientific calculations which were CPU intensive. It therefore found favour in those environments. The biggest benefit of HASP that the installation I was at; was better use of printers without having to dedicated devices, as previously, or spool prints to tape for subsequent printing. All of these predated MAS and NJE. In terms of IBM preference, it is always difficult to be certain. On the one hand IBM did seem to adopt JES2, but shipped both arguably for compatibility reasons I guess. In the 1980s I did get involved with a small, 4381 site, which had been talked into purchasing JES3 even though it was unlikely that they would benefit from many of its features. (This was at the time there was a drive to move installations from VSE to MVS.) The real issue these days I think is, "Is there a need for both JES2 and JES3?" To what extent if any does SysPlex align the products such that IBM could concentrate development on only one? In the meantime it is horses for courses, although I doubt that anybody will convert from one to the other, as it is not necessarily a trivial exercise. Kind Regards - Terry Director KMS-IT Limited 228 Abbeydale Road South Dore Sheffield S17 3LA UK Reg : 3767263 Outgoing e-mails have been scanned, but it is the recipients responsibility to ensure their anti-virus software is up to date. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
