Tim Ledgerwood wrote:

>He would like to install the DBMS software on several machines.
>
>Each DBMS engine looks at the same database (in IB/FB terms, the GDB file)
>file over the network.
>

If we had a current VMS port, and if he had a VAXCluster, then it would
work fine. The problem with clusters is to prevent the different
servers from stepping on each others' changes. On a single system, in
Classic mode, the various client processes use the lock manager to
indicate that they need exclusive control of a page before writing it
out. The trick in a cluster is to have some similar process that
manages locks between all servers in the cluster. VMS has one. There
are other clusters with lock managers, and with a certain amount of
pain, our lock semantics could be grafted onto theirs. The question is
whether the lock manager would be such a bottleneck that the whole thing
would be slower than a single processor...

Regards,


Ann