How to improve performance

I am currently executing a update query on a table with 150 K records.

The query is update customer set status = '1' where status is null;
Status is not an indexed field and 99% of the records will be affected.

Its been running for an 90 min already. If it finished now it would have
processed roughly 30 records per second. Is this reasonable? What can I do
to improve performance.

I would think this would be a disk bound process but vmstat is currently
showing about 4% CPU idle. This is on a P II 350 with 256 MB RAM and an IDE
hard drive. We are running Red Hat 5.2 (Linux 2.0.36) and Postgress 6.4.0.

Bryan White
ArcaMax Inc.
Yorktown VA
www.arcamax.com