Apologies for my "late" response re: UIDE v.s. VirtualBox. Had to have
my (infected!) gall-bladder removed, 25-Jun-2011. NASTY episode, and I
am still recovering and "moving a bit slow" on driver work! Re: recent
EDR-DOS forum posts, I say the same as our author Mark Twain once did --
"The rumors of my demise are greatly exaggerated"!
As I have noted, UIDE is designed to run real "hardware" PC systems, not
software "emulators". Full-and-complete emulators like VMWare cause no
problems. But, from the error reports, VirtualBox seems not to emulate
ATA "Identify Device" commands (gives long timeouts!) and may not handle
all EDD BIOS requests (gives "EDD BIOS data ERROR" messages!). UIDE is
written to "match" EDD BIOS disk I-O addresses with those same addresses
from its PCI controller scan. Only the PCI BIOS "knows" which UltraDMA
addresses it assigned to each controller. If such a "match" fails, any
affected hard-disks are IGNORED, as UIDE cannot use UltraDMA for them!
With VirtualBox, or other similarly "incomplete" emulators which prevent
UIDE's hard-disk setup logic from succeeding, UIDE can use its "call the
BIOS" logic instead, like it does for diskettes and for any non-SATA/IDE
disks that may be in use. I am assuming VirtualBox does NOT affect how
the normal BIOS disk I-O routines operate, which would be truly IDIOTIC!
So, I have added a /E ("emulator") switch to UIDE and UIDE-S. /E makes
the drivers "call the BIOS" on every hard disk I-O request. This means
UIDE can "go around" most of its hard-disk setup logic and simply assume
the BIOS "knows what it is doing" with disk drives. CD/DVD drives that
were never part of the PC BIOS still require UIDE's setup logic to work,
or they will not get "detected" and used. /E causes a minor speed loss
(5% or less) in UIDE's cache speed, due to calling another "driver" (the
BIOS) and since disks will be unable to use UIDE's XMS cache buffers for
direct I-O. But, unlike /N1 which totally ignores hard disks, /E still
allows hard-disk data to be cached after BIOS I-O requests, and it ought
to let VirtualBox run O.K. with UIDE and UIDE-S. I don't use and don't
want VirtualBox, so I must let users tell me if /E works as intended.
But, one BIG problem -- Many "El Cheapo" BIOS programs (including mine!)
have no DOS "Virtual Data Services" logic that tells a driver the 32-bit
address of I-O buffers. When a DOS system uses protected-mode (JEMM386
etc.), no VDS logic says the BIOS can only do slow "PIO mode" transfers!
On my system, using JEMM386 and UIDE /E, file copies run 6 times slower,
even with UIDE's cache trying to help! Since I don't live in Taiwan or
speak Mandarin, there is little I can do re: how mainboard makers design
their (wretched) BIOS programs. Thus, users who require VirtualBox and
desire to run UIDE /E with it should avoid enabling protected-mode, when
possible, to prevent serious "El Cheapo BIOS" speed losses!
I have sent an updated 22-Jul-2011 DRIVERS.ZIP file to Johnson Lam, with
the /E switch added in UIDE and UIDE-S, for Johnson to test. He is my
"partner" in these drivers (and a better software "tester" than me!), so
the latest UIDE will not be "official" until he accepts it. Johnson is
unavailable this weekend, so anyone who wishes to try the new UIDE /E on
a "test basis" can E-Mail me, and I will send you the file. Do give me
an E-Mail address for you that accepts .ZIP files -- GMail and others do
NOT accept them, due to spammers/abuse! My complete E-Mail address is:
gykazequios "at" earthlink "dot" net
Also, Japheth tells me VirtualBox has been updated, and his XDMA32 "JLM"
driver is now O.K. with JEMM386 and the new VirtualBox release. None-
theless, I still intend to offer UIDE /E for all users, as there may yet
be other "emulator" problems, and since using "call the BIOS" logic with
hard disks could be valuable in other "odd" cases as well.
Jack R. Ellis
------------------------------------------------------------------------------
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