A "Heads Up" (warning) message to all users of UIDE and UIDE2 --
Some time ago, I considered "Read-Ahead" for UIDE/UIDE2. But effective
Read-Ahead requires knowing file sizes, to prevent reading too FAR ahead
and losing time! File sizes demand DOS calls, and I want UIDE/UIDE2 to
remain "generic" (no DOS calls) and continue to use only Int 13h.
In any case, I did revise the drivers' "UdmaIO"/"DoDMA" routines, to put
more setup logic in "DoDMA" so it could be an "internal driver" for Read
Ahead. This created a "bug"! For disks, the "SetAdr" subroutine that
detects "64K UltraDMA boundary" crossings is now being called BEFORE the
"IOLen" byte count is set for requests! "SetAdr" must know that count!
CD/DVD requests, and the non-caching UIDEJR driver, were not affected.
Easy to fix, simply re-arrange UIDE/UIDE2's logic to what it was before.
However, what this "bug" IMPLIES has left me rather DISGUSTED!
I shall NOT believe that all DOS kernels/programs do disk I-O using only
perfectly-aligned buffers with no "64K UltraDMA boundaries"! Many such
kernels/programs were written BEFORE 1994, when UltraDMA was thought-up!
So, the only way recent UIDE/UIDE2 drivers could run O.K., without users
seeing a LOT of data errors, is that "64K UltraDMA boundaries" NO-LONGER
EXIST! Newer DMA controller chips likely increment all 32 address bits
after DMA byte/word transfers, not just the LOWER 16 bits as in the 1994
Intel "Bus-Master" Specs. That was what created such "64K boundaries"!
And NOBODY in Santa Clara, California nor in Redmond, Washington told ME
one word about all this, that UIDE need no-longer "worry" about UltraDMA
boundaries! This despite comments about UIDE "showing up" all the time
on MSN and others of their "forums"!
So, pardon me, if I am really left DISMAYED and DISGUSTED by the current
"computer industry", that PROVES all-the-time how they only want DOS and
efforts like ours to just "go away"! Small wonder, that my computer is
unchanged past 2006, and my software is unchanged past 1994 V6.22 MS-DOS
and 1998 V4.0 Windows/NT. I too can play their little "go away" game,
or as my late Mother might have said, "So SCREW them"!!!
I have the "bug" fixed in my personal drivers, and I shall soon issue an
updated DRIVERS.ZIP file through Johnson Lam's website, when he recovers
from another type of "bug" called the FLU!
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