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Your Problems. (Miscellaneous)

posted by Jack, 29.10.2007, 22:29

> Yes, I also think that write caching is not needed in this moment. We all
> know how dangerous it can be. F.e. combination of driver Hyperdsk.exe and
> (beautiful) game Furry of the furies always resulted in damage of game
> files.
UIDE uses "Write Through" caching. Output data is cached but is written to
disk immediately, saving MUCH logic. Subsequent reads of the same data are
from cache (XMS memory), not from the disk, for faster speed. "Write Back"
caching is different. Writes are delayed in case the same disk sectors are
updated again quickly, as with databases, etc. This does save time. But,
it is VERY complex and RISKY, as you've noted! UIDE shall remain "simple"!

> Anyway - there is a huge room for improvements in FreeDOS kernel for it.
I agree. All other DOS kernels but ROM-DOS (bad XMS/EMS drivers!) do allow
UIDE to put its cache logic and binary-search tables in the HMA. This lets
UIDE reside in only 1.75K of upper-memory. FreeDOS does NOT permit any HMA
usage by drivers loaded through the CONFIG.SYS file. They should fix this.

> But I see two points which could be improved in UIDE:
> 1) Option for disabling the CD/DVD module. Why: it doesn't work with my
> LiteOn DVD drive if it contains a DVD disc. (for CD discs is it OK)
> Now I have a different DVD drive, so it is not so important for me ...
> ...And this issue is not specific only for UIDE - many others CD/DVD
> drivers has problems with LiteOn.
I agree. LiteOn is known as an "El Cheapo" brand, with MANY problems! So
I will not put more code in UIDE "only for them". Their problem, not mine.

> 2) add option for creating cache above 4MB of memory. Why: SB emulation
> drivers use this area (under 4MB boundary). When is it already occupied
> by UIDE (UIDE loaded by config.sys, SB by autoexec.bat or "on-demand") SB
> emulation will not start.
If SB drivers demand memory below 4-MB, can you not load them before UIDE in
CONFIG.SYS, even if "DEVLOAD" or similar must do such loading?? I had such
a scheme in QCACHE but removed it from UDMA/UIDE, since it required "playing
games" with the XMS driver! UIDE just asks for one block of XMS memory, to
remain SAFE with whatever XMS driver is used. I dare NOT "trust" them all!

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