On 6/12/2020 10:54 PM, Thomas Mueller wrote:
support still is larger and slower than a 386 kernel on 386, so
you are just needlessly tempting 386+ owners to run extremely
retro-compatible, less optimized kernels ;-) Also, FAT32 is not
just a module which could easily be unloaded, it is the entire
set of MS DOS 7.10 compatibility things compared to MS DOS 5/6
and using 8086 FAT32 kernels wastes a lot of memory on the 99.99%
of PC-XT which have less than 2 GB disk size, while using 8086
kernels of any type on 386 or newer CPU is generally not cool.
Oh, I just meant for the 8086 kernel.
And yes, without that being the intent prior to creating the support for
FAT32, it would probably be a major pain to restructure it into an
easily loaded/unloaded driver.
some facts, from my head, and 19 years old. your exact mileage may vary,
depending on compiler, 86 or 386, but the general outline should be
still correct.
FAT16, FAT12 and FAT32 code are the mostly the same; there is no separate
FAT32 driver. there is some code for FAT32 where FAT32 is really
different from FAT16/FAT12.
most of the size increase (~3,5 K) is because a CLUSTER is no longer
16 bit, but 32 bit as required for FAT32, so the code can be used for
both FAT16 and FAT32.
some size increase (~1,5 K) comes from actual FAT32 specifics, that at
least theoretically could be unloaded.
a hugely better investment of programmer time would be to teach FreeCOm
to swap to disk (instead of swap to XMS), reusing the code for XMSSwap.
probably easier, and easier to debug (it's a mostly normal program)
for the benifit of 60+K instead of ~1K.
still, my personal opinion remains:
if a virtual PC allows 8086 CPUs, it should give them 256 KB memory
and at most 20 MB disk space and at most 8 MHz performance.
8086 PC's are museum pieces, and should be running MSDOS 2.01 or
whatever they happen to have installed.
Tom [Ehlert]
I took a computer course at now-defunct Kentucky Polytechnic Institute (KPI) in
1990.
They used 8086 PCs with 30 MB hard drives and MS-DOS 3.31; 640 KB, or was it 1
MB, RAM.
So why should a virtual PC be limited to 256 KB memory and 20 MB disk space, if
indeed an 8086 or 8088 PC is really worth emulating?
First PC I had was 386 SX CPU with 40 MB MFM hard drive; OS was MS-DOS 4.01.
Tom
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I got my first pc in 1994. It was an XT with a meg of ram, 60meg hard
drive, dos 5.0 upgraded to 6.0. I bought it off a friend who had
(obviously) upgraded it over the years.
It's one thing to recommend a specific configuration to recreate a
certain period in time. It's another thing to say "things ought to be
one way, and one way only".
Even looking back, the hardware wasn't that limited. For example:
https://en.wikipedia.org/wiki/IBM_Personal_System/2#Models
From what I'm able to tell (reading the wikipedia article) DOS 3.3
seems to be what came with them.
I semi-evangelize 86Box, in part because it emulates so many different
models and configurations. If it was the PC and nothing else that would
get very boring, very quickly.
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