What are typical buffer manager I/O overheads?
 

Dear All:

I was reading Stonebraker's paper on Operating System support for databases, and came across a statistic - "For a PDP-11 UNIX system, it takes the buffer manager 5000 CPU instructions to fetch a 512 byte block from disk, and about 1800 to fetch a single byte." Does anyone have an idea as to similar statistics for contemporary Linux/UNIX systems?

-Regards and Thanks,
Suman.