How does filling a disk to capacity affect performance?

[Mark Rosenthal]

In article <1508 at se-sd.sandiego.NCR.COM> rns at se-sd.sandiego.NCR.COM (Rick Schubert) writes:
>"cp" may be "dumb" (not meant to be derogatory to "cp" or to people who
>are unable to speak) enough not to check whether or not a write was successful
>(I haven't bothered to test whether or not it is because that's not my point),
>but it doesn't have the permission to start writing over blocks that are not
>free

Just a side note.  As I understand it, checking the return value of write()
does not really tell you what you want to know, due to the fact that write's
happen asynchronously.  All the return value can tell you is whether the data
was successfully copied into the kernel's buffer.  Then when the disk is not
busy and kernel gets around to it, the actual write happens, by which time your
process is off doing other things, or perhaps has already exited.
-- 
	Mark of the Valley of Roses
	...!{harvard,ima}!bbn!aoa!mbr