Date: Wed, 17 Dec 1997 10:13:11 +1300 From: physmsa AT cantua DOT canterbury DOT ac DOT nz (Mr M S Aitchison) Subject: Performance questions & Re: OD7.02B - Should I upgrade to it? To: opendos AT delorie DOT com Message-id: <199712162113.KAA12189@cantua.canterbury.ac.nz> Precedence: bulk Lots of small files imply lots of work scanning directories. One thing is to put the most important directories first in your path, another is to not have a directory with lots of data files yet only a few executables in your path (it may be more efficient to have a directory with batch files containing the exact pathnames early in your path, and possibly on a RAMDISK). I have found in the past that setting buffers to something significant, even with a cache, improves speed. Without a cache it is easy to tell the problem with anything doing findfirst/findnext (e.g. a directory listing) when the number of buffers is less that (number of entries in a directory/16), as soon as you go beyond what is in the buffers there is a huge amount of disk activity (it seems findnext has to go all the way through previously-read directory blocks just to get to the next one). With a cache, even though they should all be cached, it seems there is still enough system overheads getting previous dir blocks from RAM to make searching the path for commands take noticeably longer when there aren't enough buffers. (I should have tried it again to check, before saying that, but the important thing is that you can often easily increase high buffers to consume RAM in the HMA that would otherwise have been left unused after putting bits of the Kernel and share there - I find I can fit about 22 there without reducing the RAM for anything else). Does verify=on only apply to diskettes? I don't trust diskettes, and since the reason I use them is to carry small-but-important files a long way, I hate the trip to be wasted, so I agree turning it on is a good idea despite the performance hit on diskette writes. I find diskette reads slower under DRDOS/Novell DOS/OpenDOS (haven't tried the 7.02B yet properly, so I'm interested in technical information of the improvements like the original poster). If you specify FILESHIGH and there isn't enough RAM up there for all of them, do the file handles that are used *first* or *last* get put into the (sometimes faster) conventional memory? I used to have a driver that provided a combination of Disk cache and RAMDISK, where partially using the RAM disk would mean more RAM was lent to the cache. Does anybody know of a RAMDISK (VDISK) that could be used with NWCACHE to share unused RAM between cache, ram disk and other programs? ------------------------------------------------------------------------- Mark Aitchison, \_ Phone: +64 3 364-2947 home 337-1225 Dept of Physics & Astronomy,