On 7 December 2012 08:22, McKown, John <[email protected]> wrote:
> I'd lay good odds that most of the DCB oriented stuff will stay RMODE(24) 
> until the end of the age of mainframes. So much code is dependent on 3 byte 
> addresses that even if IBM wanted to update it, end users would revolt when 
> their applications which used 3 byte addresses from the 1980s abended. I 
> remember the nastiness when SWA went above the line and what was an address 
> became a token. Everybody had to either keep SWA below the line (an option), 
> or rewrite their code to use the SWAREQ(?) macro instead of "chain chasing".

Some even older of us will remember that in pre-MVS days those 3-byte
values were TTRs in SYS1.SYSJOBQ, and it was a pleasant if short-lived
and short-sighted thing to be able to just look at memory instead of
scheduling I/O.

Tony H.

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