John,

First, you do realize that you are running your dev server at the
absolute minimum memory requirements for Win2K Adv Server. I suspect
that you have virtually no free memory for applications/server or
file/disk cache.

Second, I would recommend that you change the DATABASE_CACHE_PAGES
setting in the IBConfig file to a value of at 2048, perferably 4096.

Third, what is the page size of your database file? It should be at
least 4096 in size. In some cases, a large page size (16KB) will also
improve performance.

Fourth, is your system a multi-CPU unit? If not, why are you running
Win2K AdvServer instead of Win2K Server? (Just curious on this one)

Next, try restating your statement, to use the SQL-92 join syntax as:

UPDATE ENROL E
SET REVENUE_NO = (
SELECT REVENUE_NO
FROM REVENUE_FACULTY RF
Join STUDENT S on S.OS = RF.OS
WHERE S.STUD_NO = E.stud_no
AND RF.CRT_NO = E.crt_no


Sean