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"Enlightenment" (Announce)

posted by Jack R. Ellis E-mail, 28.09.2007, 15:31

> If Japheth or anyone else doesn't appreciate the miracle of the newer
> drivers, then enlighten them. Insulting people for nothing does not
> open their minds.
Very well!!

Try a simple test. Run whatever DOS variant you like with NO EMM386,
JEMM386, or anything equivalent, and with NONE of my UltraDMA drivers.
Run whatever set of disk copies/compares you like, and note the speed.

Then, reload your DOS system using exactly the same configuration, and
do exactly the same test again. But THIS time, use "Debug" and patch
location 0:47Bh from 014h to 034h, BEFORE you run your test. I would
bet you "Dollars to Navy-Beans" that by adding the 020h bit at address
0:47Bh, your second test runs 5 or 6 times SLOWER!

What does the 020h bit at 0:47Bh denote? That "Virtual DMA Services"
are active, which many usual "El Cheapo" BIOS programs DO NOT support!
Without VDS, i.e. with no ability to find the "virtual 32-bit address"
of a user I-O buffer, a "cheap" BIOS must use only "PIO mode" for data
transfers! I hope I do not have to tell you how SLOW "PIO mode" is!!

Who must set the 020h bit at address 0:47Bh?? ANY driver that sets a
system in "protected mode" and so demands "virtual 32-bit addressing",
i.e. EMM386/QEMM/386MAX ... and JEMM386!! This is why my README file
for XMGR/UDMA/UDVD no-longer recommends running ANY hard disk in a DOS
system using only BIOS I-O. Too many people DO load "protected mode"
memory managers that require "VDS services", and too many "cheap" BIOS
programs will then RUIN your hard-disk speed!!

About caching, and despite comments by others that SATA disks are fast
enough that they do not NEED caching, I shall only say: Try your OWN
tests of whatever DOS you like, with and without caching. My system
performs TWICE as fast writing files and slightly faster reading them,
when I do load UDMA, even using its 5-Megabyte "minimum" cache. But,
don't just "take my word" -- TRY IT YOURSELVES, before you believe any
BULL**** that SATA disks now do not require caching in DOS!!

As for caching CD/DVD drives, in the face of their miserably SLOW seek
times, do try copying "loaded" 635-MB CD platters (I use an old NVidia
Driver CD) from CD to disk. Just use "XCOPY F:\*.* C:\TEST /S" or an
equal /S command, which copies EVERYTHING from CD to a disk directory.
Note how fast it runs using UDMA/UDVD and caching (usually 125 seconds
for me). Then, try it WITHOUT caching, i.e., use UDVD but do not use
UDMA. 195 seconds for me, and I bet "Dollars to Navy Beans" that you
get a similar LOW speed with your systems. With no caching of CD/DVD
directories, CD/DVD seeks will MURDER you!!

But again, don't just "take my word"!! TRY all this, for YOURSELVES,
especially setting the 020h bit at 0:47Bh!! THAT should prove to you
the kind of total CRAP that most mainboard vendors put in their BIOS!!
After that, if you still wish to believe "False Prophets" re: the need
for UltraDMA drivers and for caching, I have a Bridge in Brooklyn that
might be of interest to you!!

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