chris@mimsy.umd.edu (Chris Torek) (08/20/90)
In article <38254@ucbvax.BERKELEY.EDU> edward@ucbarpa.Berkeley.EDU (Edward Wang) writes: >A result of a study I did a while ago is that failed lookups often >repeat ... and caching this information brings the hit rate ... up >quite a bit. (The cache would contain files known not to exist.) >My impression is that BSD does not do this. >Does anyone here know why? 4.3BSD and 4.3BSD-Tahoe do not, but 4.3BSD-Reno does. As to why... probably because Kirk did not think to do it at first. It is easy enough to add: just make a cache entry with a nil inode/vnode pointer. (The 4.3BSD code panic's on such an entry, which provides an existence proof that none now exist :-) .) -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163) Domain: chris@cs.umd.edu Path: uunet!mimsy!chris (New campus phone system, active sometime soon: +1 301 405 2750)