DOS ain't dead

New Slightly-Faster UIDE Driver Available. (Announce)

posted by Jack , Fresno, California USA, 20.05.2010, 15:30

Johnson Lam has posted a new DRIVERS.ZIP file, dated 19-May-2010,
and containing a slightly faster UIDE driver, on his website at:

<http://johnson.tmfc.net/dos/driver.html>

The XMGR, RDISK, and UIDEJR drivers are unchanged and have merely
been re-dated 19-May-2010 to "match" the new UIDE driver.

In UIDE, doing both a "get" and "put" while updating cache least-
recently-used (LRU) indexes was not needed! Only one 2-byte LRU
index changes in such updates, and the driver need not handle the
full 12-byte entry. UIDE now computes where an LRU index is, in
XMS memory, then issues only a 2-byte "put" (at label "LRUPut" in
UIDE.ASM). This AVOIDS also doing two "gets" from XMS memory of
the two LRU indexes in every cache block, making UIDE run faster.
My apologies to all -- I should have realized this idea long ago!

Also, for a "hair" more speed in protected-mode, the /K switch is
again available in UIDE. /K causes a direct "call" to the logic
in JEMM386 that does an XMS move, which is slightly faster than a
regular "Int 15h" that needs full protected-mode "trap handling".
However, as noted in the driver README file, /K is NOT for use on
Win95/98/3.11 systems and will demand TESTING if other protected-
mode or VCPI/DPMI handlers besides JEMM386 or EMM386 are present!

I did complete a "memory only" version of UIDE, but it needed TOO
MUCH memory, up to 119K for a 511-MB cache! Thus, I decided to
keep the current UIDE, but include the above minor speed changes.
Not a large speed increase, but such small changes do add-up over
time! I will continue trying to find faster UIDE "schemes".

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(Account disabled on user's request.)

Complete thread:

• New Slightly-Faster UIDE Driver Available. - Jack, 20.05.2010, 15:30 (Announce)
  • A "White Paper" On Using UIDE. - Jack, 21.05.2010, 17:38