Hmm... RedHat 7.0 is a solid 2 years old if not more.. I did a search and easily found messages from people installing it in 2000. Since then there have been 7.1, 7.2, 7.3, 8.0 and even now a beta 8.1 release of RedHat Linux. Upgrades are quite easy and almost always painless (YMMV but I've done more than a dozen).
7.0 uses a 2.2 series kernel, has no journaling filesystem support, etc... It's really dated at this point. Newer versions are free if you download and burn the ISO yourself or <$200 to purchase the boxed version which comes with manuals, etc...
Having said that, sorry no I don't know how to change the semaphore value. I did a quick search on "redhat 7.0 oracle" on yahoo though and found this:
http://jordan.fortwayne.com/oracle/8161.html
it lists some "issues" with installing on RH 7.0 so be warned...
