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From: lane@dalcs.UUCP (John Wright/Dr. Pat Lane)
Newsgroups: comp.sys.ibm.pc
Subject: Disk Cache programs vs. BUFFERS=: Whats the diff?
Keywords: disk cache, DOS buffer
Message-ID: <3017@dalcs.UUCP>
Date: 6 Oct 88 12:46:22 GMT
Distribution: na
Organization: Math, Stats & CS, Dalhousie University, Halifax, NS, Canada
Lines: 28

What are the differences and what is the performance advantage in using
a disk cache program verses the DOS buffer system (controlled with BUFFERS=
in the CONFIG.SYS file).  Assume for the sake of argument that 640K RAM is
available.  I can see the following minor points:
-  Caches are typically larger (64K up) than, say 20 buffers (10K of actual
   buffer space), thus keeping more disk in RAM (faster access vs. less
   available memory).
-  Cache programs can usually be turned on and off or applied to specific
   drives.  Those that are resident programs (not installable drivers) can
   in some cases be removed from memory.
-  A cache program would have some memory overhead for the program; the code
   for DOS buffers is there whether you take advantage of it or not.
-  Some cache programs can put the cache in extended or expanded RAM which
   would be a major memory advantage.
So what would be the difference between defining BUFFERS=128 vs. using a 
64K cache?  If you have a disk cache are you just as well to set BUFFERS=3
or less?  Are some caches better than others?  Are caches in extended or
expanded memory significantly slower than those in base memory or DOS buffers?
How would DOS 3.3's FASTOPEN factor into this?

Thanks for any opinions?

...JW
-- 
John Wright      /////////////////     Phone:  902-424-3805  or  902-424-6527
Post: c/o Dr Pat Lane, Biology Dept, Dalhousie U, Halifax N.S., CANADA B3H-4H8 
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