In <[email protected]>, on
10/27/2011
at 12:20 PM, glen herrmannsfeldt <[email protected]> said:
>As I understand it, Fortran variables, and DS in assembler, generate
>holes in the object program (no TXT record for that position), and
>are filled in either by the linkage editor or program fetch.
Not quite. The exact processing depended on the region size, but in
general the Linkage Editor packaged program data into text records,
with gaps when going to new csects. There might or might not be a gap
for a DS, depending on the size of the text record being built. So the
area for a DS might have residual data in a text record, or it might
have residual data from the storage allocated by Fetch.
>I believe that early OS/360 versions left whatever happened to be
>there, either in the linkage editor buffer or, for program fetch, in
>that memory location. At some time later, possibly for security
>reasons, this was changed to initialize to zero, or maybe something
>else (such as X'81').
I'm not aware of IBM making any such change. Perhaps you had a local
mod from, e.g., SLAC?
--
Shmuel (Seymour J.) Metz, SysProg and JOAT
ISO position; see <http://patriot.net/~shmuel/resume/brief.html>
We don't care. We don't have to care, we're Congress.
(S877: The Shut up and Eat Your spam act of 2003)
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