On Sun, 12 Jan 2020 19:41:07 -0500, Matt Hogstrom wrote:
>That was my thinking too Paul. We should be able to mask a lot of this in
>software and not have to do a lot of unnecessary “busy” work.
>
>Part of the challenge is to identify some behaviors that could be deprecated.
>We have a lot of baggage in the z/OS wagon. The defrag comment got me to
>thinking about possibilities that we at Ibm might start to consider
>
"we at Ibm"? But I see no IBM in your return address. But some prefer to
avoid such identification.
---------------------------------------------
On Mon, 13 Jan 2020 10:21:22 -0600, Tom Marchant wrote:
>
>..., as long as z/OS still allocates data set space in a small number of
>extents when the data set is defined, these are still issues.
> ...
>Can the pointer to the next track be on a different volume? One might
>argue that the notion of volumes is no longer as useful as it was with
>emulated volumes. That might be a valid argument, though eliminating the
>notion has consequences for things like spool volumes, page volumes.
>
Paging needs to be close to the hardware for performance. Spool
less so. Early OS just used Classic data sets for spool. There were
operational problems, addressed by HASP. IBM, characteristically,
did not make such enhancements generally available, but restricted
them to HASP/JES.
>What happens when additional drives are added to a DASD subsystem? Can
>a data set be spread across multiple DASD subsystems?
>
>It is not clear to me that this kind of architectural change would be an
>improvement, especially for data sets that can be accessed randomly.
>
Tunnel vision. Indexing?
https://en.wikipedia.org/wiki/Btrfs
As readers familiar with my biases, I'd urge that such enhancements
ignore older conventions and concentrate on PDSE and zFS which have
already overcome some of the older limitations.
Does PDSE versioning exploit CoW?
-- gil
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