ETXTBSY

[Fairlight]

Simon--er, no...it was J. P. Radley--said:
> 
> | However, like all diamonds, it has flaws.  ETXTBSY is no longer
> | supported.  This is pretty much a result of one of the key aspects
> | of the VM design, which is that there is only one copy of a given
> | file page in the system for all uses.  Thus, any attempt to put back
> | ETXTBSY is going to be so expensive that it's not going to be worth
> | it unless there is some huge revenue opportunity that is going to be
> | lost simply because ETXTBSY is not supported.  This seems an unlikely
> | scenario.

Use a hash of binaries with pages currently in memory, and check against
the list of currently-running binaries before allowing the procedure.  If
it's in use, generate the error.  Increment the hash entry's counter value
every time a new one starts, and decrement it when one exits.  Delete the
hash key entirely when the counter reads zero.

Given that they only have -one- copy in memory at a time, a hash table
should remain small, fast, manageable, and inexpensive.

mark->
-- 
There is no "I" in TEAM.
This would be the primary reason I've chosen not to join one.