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Re: UIDE Unloading And Cache-Sizes. (Announce)

posted by Jack E-mail, Fresno, California USA, 07.06.2010, 05:30

>> I consider UIDE to be a "hard" SYSTEM driver, one which caches
>> essential devices like the system hard-disk and CD/DVD drives,
>> and thus people should NEVER want to unload it! ...
>
> The only reason (IMHO) to unload would be to free up precious memory
> without requiring a reboot. And most users don't have any shortage
> of RAM, esp. for DOS apps.
One has to be "Quite DESPERATE!" for memory, if saving the 944 bytes
of upper-memory used by the current UIDE is actually THAT important!

> However, I still think 15 MB used of 32 MB is too much, which you
> suggested once; heck, I even tested it, couldn't find any speedup,
> so I stick to 5 MB on that old clunker.
"The theory" of UIDE's caches is that, if possible, you should set a
cache TWICE the size of your largest data file, PLUS extra memory so
a reasonable amount of DOS directories can remain "in cache" and not
get discarded, when more new data arrives. Keeping DOS directories
"in cache" is the GREATEST advantage of using UIDE, as DOS otherwise
does only SLOW "designed in 1981" single-sector directory handling!

Using a 5-MB cache, if you have no files larger than about 2-MB, you
can copy such files using 4-MB of cache (2 for input, 2 for output),
and you still have about 1-MB left for directories. When DOS wants
to copy another file or load a new program, it loses NO speed, since
the directories were not discarded due to too-much "new" cache data.

Many DOS-only systems (NO Windows!) have only such small files, thus
a 5-MB UIDE cache is still useful for them. However, try copying a
BIG 100-MB file or more with only a 5-MB cache, and you will "see" a
speed loss, which you would NOT see if using a 250-MB cache or more!
The loss is small, and UIDE re-inputs discarded directories quickly.
But for BEST speed, do set UIDE cache sizes using "the theory" above!

---
(Account disabled on user's request.)

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