parnes@eniac.seas.upenn.edu (Gary Parnes) (12/16/89)
Sorry! I guess what I was intending to ask about is not what I meant. What I was really looking for was a way to turn extended memory into disk caching memory. Or is this automatic? Using Dos 3.x right now... Gary /=============================================================================\ | "You're obviously misinformed... everything | Gary Parnes | | EAST of the San Andreas Fault is going to | Computer Science Engineer | | fall into the ATLANTIC Ocean." | University of Pennsylvania | | *** parnes@eniac.seas.upenn.edu *** | *NOT* Penn State, Dammit! | \=============================================================================/
kaleb@mars.jpl.nasa.gov (Kaleb Keithley) (12/16/89)
In article <18166@netnews.upenn.edu> parnes@eniac.seas.upenn.edu (Gary Parnes) writes: >Sorry! I guess what I was intending to ask about is not what I meant. > >What I was really looking for was a way to turn extended memory into >disk caching memory. Or is this automatic? > >Using Dos 3.x right now... > Upgrade to 4.01, which includes SMARTDRV.SYS, a disk cache device driver. Performance index, as returned by CORETEST went from 6 to 30, before and after cacheing. Transfer rate went from 800,000 bytes/second to 5Mbytes per second. SMARTDRV works in extended memory, and may work in expanded memory, but I'm to lazy to look in the book to see. Chewey, get us outta here! kaleb@mars.jpl.nasa.gov (818)354-8771 Kaleb Keithley
cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) (12/17/89)
In article <18166@netnews.upenn.edu> parnes@eniac.seas.upenn.edu (Gary Parnes) writes:
$What I was really looking for was a way to turn extended memory into
$disk caching memory. Or is this automatic?
When it comes to extended memory, nothing is automatic. And there is a _big_
difference between a ramdisk and a disk cache. HAving said that ...
Recent versions of DOS have, I believe, been shipped with either IBMCACHE.SYS
or SMARTDRV.SYS (I know all the PC-DOS 3.30s and above at work last summer
had IBMCACHE), which will work in extended memory. If you have a recent
version of PCTools, it includes PC-Cache. I forget who Central Point
licences that from, but whoever it is has an even better version (is it
PC-Kwik, the shareware disk cache?). There are also lots of disk caches on
many BBSs.
--
Stephen M. Dunn cs4g6ag@maccs.dcss.mcmaster.ca
<std_disclaimer.h> = "\nI'm only an undergraduate!!!\n";
****************************************************************************
If it's true that love is only a game//Well, then I can play pretendcs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) (12/17/89)
In article <2418@jato.Jpl.Nasa.Gov> kaleb@mars.UUCP (Kaleb Keithley) writes:
[using SMARTDRV.SYS]
$Performance index, as returned by CORETEST went from 6 to 30, before and after
$cacheing. Transfer rate went from 800,000 bytes/second to 5Mbytes per second.
Transfer rate figures are next to meaningless when you have a disk cache
installed, because they work by repeatedly reading a small number of tracks,
so with a cache they only actually get read once and then they are read from
the cache. Most of the time in the real world, this is a very unrealistic
assumption. My hard disk without a cache performs at about 200K/s; with a
384K cache in expanded memory, that jumps by a factor of ten. However, I
haven't noticed my compiles getting anywhere near ten times faster (try
maybe 40-50% ... just a guess).
The only time you even begin to approach that kind of performance boost
is if all of the files you're accessing (including any executables if you're
jumping back and forth between programs) total less than the size of the
cache and you're not writing too much data back to disk. Other than that
sort of situation, the numbers generated by CORETEST (or any other similar
program, for that matter) can be thrown into the recycling bin.
--
Stephen M. Dunn cs4g6ag@maccs.dcss.mcmaster.ca
<std_disclaimer.h> = "\nI'm only an undergraduate!!!\n";
****************************************************************************
If it's true that love is only a game//Well, then I can play pretend