"last reference" is the date of the last successful open of the file,
regardless of whether for input or output. Allocation without
opening the file does not change the last reference date.
Michael
At 03:30 PM 8/2/2024, Phil Smith III wrote:
Billy Ashton asked how to do the equivalent of a USS "touch" on a
z/OS data set.
I'm wondering if there's something like the C "DD:ddname" filename
specification hack that could be used. I know this would seem odd:
run a batch job that uses BPXwhatever to run USS "touch", but if
it's possible...?
This makes me realize that I don't know what "touch" actually does.
I mean, I know the effect, but what does it have to do to make that
happen? If it's some filesystem function, a minimal C program might
be able to use the "DD:ddname" hack and that function. Googling
suggests that it just opens the file and that that's sufficient to
update it, but there has to be more, since it can optionally update
just the last access time, without updating the last changed time.
In fact, the more I think about this, I now wonder what "last
referenced" even means; I assume it's time of last access, not change?
Billy wrote, in part:
> We don't want to do things like allocate, open, and print one record,
> as some of these files are huge (25-50GB).
Would you need to print a record to update "last referenced"?
Shouldn't reading a record suffice? Do you even need to do that? Why
does the size of the file matter here?
I'm sure these are dumb questions but my in-depth filesystem
knowledge is for other OSes, so I'm just knowledgeable enough to be curious...
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