winscape 2261

Here in alt.folklore.computers,

Just a word from the peanut gallery, but that's our working definition of "re-entrant" in the Unisys transaction (TIP-HVTIP) world. A shared copy of either an instruction bank (IBANK) or data bank (DBANK) that is kept resident in core and reused, or concurrently used, or both (since the machines typically have 2 or more IPs and often have a half-dozen or more copies of some transactions running, almost anything goes).

Even in the ancient basic mode TIP (UNIMATIC) environment I played in at NWA we could typically lock both the instruction and data banks in core for specified transaction(s), saving a little bit of load time at each transaction start for either or both types of banks, but of course concurrent use of those memory areas could be a bit problematic on the applications side without a programmer doing proper testing. :-)

That's why we always explicitly initialized all our local buffers and such by convention in each program, and why screen templates and work areas were normally kept quite separate in the data area -- we never modified static data areas because you could step on other copies of yourself! First copy the screen template into a working buffer, and *then* populate the screen template with live data.

Reentrancy-timing problems can be interesting to solve, tho, at least once you figure out how to reproduce the damn things...

-- OS-2 + eCS + Linux + Win95 + DOS + PC-GEOS + Executor = PC Hobbyist Heaven! WARNING: I've seen FIELDATA FORTRAN V and I know how to use it! The Theorem Theorem: If If, Then Then.