8 Jun
2000
8 Jun
'00
5:40 a.m.
This is what happens to you when you study biochemistry all week.
I had a perverted idea of building a DOS emulator on a C64 -- i.e., have
the C64 emulate the 8086 in software, either in real time or some sort of
JIT compilation method.
How little memory could you run something like, say, DOS 3.3 in? All I
would be supporting is a basic command set like COMMAND.COM, EDLIN, DEBUG,
maybe XCOPY, etc. And are the INTs documented anywhere?
Just a perverted idea, like I said.
--
----------------------------- personal page: http://www.armory.com/~spectre/ --
Cameron Kaiser * Point Loma Nazarene University * ckaiser(a)ptloma.edu
-- "Garbage in -- gospel out" -------------------------------------------------
8 Jun
8 Jun
6:15 a.m.
How little memory could you run something like, say,
DOS 3.3 in? All I
would be supporting is a basic command set like COMMAND.COM, EDLIN, DEBUG,
maybe XCOPY, etc. And are the INTs documented anywhere?
You could execute from disk, requiring just enough memory to hold a
disk sector. I.e., instead of reading memory by indexing into an
array like:
Instruction = Memory[ IP ];
do something like:
Block = IP >> 7; /* 128-byte sector, anyone? */
Offset = IP & 0x7f;
read( File, Block );
Instruction = Memory[ Offset ];
--
Roger Ivie
TeraGlobal Communications Corporation
1750 North Research Park Way
North Logan, UT 84341
Phone: (435)787-0555
Fax: (435)787-0516
6:20 a.m.
How little memory could you run something like, say,
DOS 3.3 in? All I
would be supporting is a basic command set like COMMAND.COM, EDLIN, DEBUG,
maybe XCOPY, etc. And are the INTs documented anywhere?
I'd guess 128k and certainly in 256k. the Command.com itself is some 27k
or 33k alone.
Allison
7:17 a.m.
::> How little memory could you run something like, say, DOS 3.3 in? All I
::> would be supporting is a basic command set like COMMAND.COM, EDLIN, DEBUG,
::> maybe XCOPY, etc. And are the INTs documented anywhere?
::
::I'd guess 128k and certainly in 256k. the Command.com itself is some 27k
::or 33k alone.
That was the thing I was worried about. Maybe I'll write Command.com natively
instead.
Someone suggested emulation from disk, and that's exactly how I was thinking
of doing it.
Where can I find a list of INTs DOS uses? I checked a couple of bookstores
but most of them aren't too helpful with low-level DOS.
--
----------------------------- personal page: http://www.armory.com/~spectre/ --
Cameron Kaiser * Point Loma Nazarene University * ckaiser(a)ptloma.edu
-- UBAX vs lbh ybir EBG-13 ----------------------------------------------------
8:12 a.m.
Where can I find a list of INTs DOS uses? I checked a
couple of bookstores
but most of them aren't too helpful with low-level DOS.
There's a file floating about the net somewhere called "the interrupt
list". It's a comprehensive list of the ints used by PC software. I have
a very old copy saved somewhere; let me know if you can't find it. Warning;
it's huge.
Barring that, "Undocumented DOS" and "Dissecting DOS" are
the ones on my bookshelf. "Dissecting DOS" presents the source code
for a DOS clone in C. I'm not seeing "Undocumented DOS" at fatbrain,
though. "Dissecting DOS" is at
http://www1.fatbrain.com/asp/bookinfo/bookinfo.asp?theisbn=020162687X
Looks like there are other interesting books as well, although I
don't know that I would buy them without getting a chance to look at
them first:
"Caldera DR-DOS Complete"
http://www1.fatbrain.com/asp/bookinfo/bookinfo.asp?theisbn=1889492035
includes a CD-ROM that I would assume probably includes the source
code for the DR-DOS kernel. That's the sort of assumption I'd like to
check out by looking at the book before I plunk down my hard-earned
cash, though. On the other hand, I already have the source to the
DR-DOS kernel lying about...
Caldera _used_ to have almost all of the DR-DOS documentation online.
I'm not finding much now (I'm sure glad I downloaded a copy of it
while it was available; now if I can just figure out where I saved it...);
there's a page at http://www.drdos.com/, but all it offers is a download
of a DOSEMU disk image for use under Linux.
"FreeDOS Kernel"
http://www1.fatbrain.com/asp/bookinfo/bookinfo.asp?theisbn=0879304367
looks to be a competitor to "Dissecting DOS".
"Uninterrupted Interrupts"
http://www1.fatbrain.com/asp/bookinfo/bookinfo.asp?theisbn=0201409666
appears to be a hardcopy of the famed "interrupt list".
--
Roger Ivie
rivie(a)teraglobal.com
Not speaking for TeraGlobal Communications Corporation
8:14 a.m.
Check out the freedos project, they've got src for their open source, GPL'd
command.com available.
http://www.freedos.org/
----- Original Message -----
From: "Cameron Kaiser" <ckaiser(a)oa.ptloma.edu
To: <classiccmp(a)classiccmp.org
Sent: Thursday, June 08, 2000 12:17 PM
Subject: Re: Perverted DOS idea
::> How little memory could you run something like,
say, DOS 3.3 in? All I
::> would be supporting is a basic command set like COMMAND.COM, EDLIN,
DEBUG,
::> maybe XCOPY, etc. And are the INTs documented
anywhere?
::
::I'd guess 128k and certainly in 256k. the Command.com itself is some 27k
::or 33k alone.
That was the thing I was worried about. Maybe I'll write Command.com
natively
instead.
Someone suggested emulation from disk, and that's exactly how I was
thinking
of doing it.
Where can I find a list of INTs DOS uses? I checked a couple of bookstores
but most of them aren't too helpful with low-level DOS.
--
----------------------------- personal page:
http://www.armory.com/~spectre/ --
Cameron Kaiser * Point Loma Nazarene University *
ckaiser(a)ptloma.edu
-- UBAX vs lbh ybir
EBG-13 ----------------------------------------------------
9:31 a.m.
On Thu, Jun 08, 2000 at 09:17:20AM -0700, Cameron Kaiser wrote:
Where can I find a list of INTs DOS uses? I checked a
couple of bookstores
but most of them aren't too helpful with low-level DOS.
People have already pointed you at Ralf Brown's wonderful interrupt list
(which BTW is available in webified form at http://ctyme.com/rbrown.htm),
but just to point out the obvious: it doesn't matter! If your emulation is
accurate enough to be useful, DOS will take care of itself. You'll probably
want to provide your own BIOS though, and for that the IBM PC or AT Tech Ref
manuals are wonderful. Computer Reset used to have NOS tech ref books at
very good prices, don't know if that's still true or even if they're still
in business. Anyway, obviously the BIOS is your chance to substitute some
native I/O w/o having to muck with DOS itself.
John Wilson
D Bit
11:25 a.m.
::>Where can I find a list of INTs DOS uses? I checked a couple of bookstores
::>but most of them aren't too helpful with low-level DOS.
::
::People have already pointed you at Ralf Brown's wonderful interrupt list
::(which BTW is available in webified form at http://ctyme.com/rbrown.htm),
::but just to point out the obvious: it doesn't matter! If your emulation is
::accurate enough to be useful, DOS will take care of itself. You'll probably
::want to provide your own BIOS though, and for that the IBM PC or AT Tech Ref
::manuals are wonderful. Computer Reset used to have NOS tech ref books at
::very good prices, don't know if that's still true or even if they're still
::in business. Anyway, obviously the BIOS is your chance to substitute some
::native I/O w/o having to muck with DOS itself.
Well, it would be a sullied implementation. I'm thinking of having a native
6502 IO.SYS and MSDOS.SYS (and probably COMMAND.COM), so the INTs would need
to be simulated by that: hence the list :-)
--
----------------------------- personal page: http://www.armory.com/~spectre/ --
Cameron Kaiser * Point Loma Nazarene University * ckaiser(a)ptloma.edu
-- Laughter is the closest distance between two people. -- Victor Borge -------
6:25 a.m.
I had a perverted idea of building a DOS emulator on a
C64 -- i.e., have
the C64 emulate the 8086 in software, either in real time or some sort of
JIT compilation method.
:))
How little memory could you run something like, say,
DOS 3.3 in? All I
would be supporting is a basic command set like COMMAND.COM, EDLIN, DEBUG,
maybe XCOPY, etc. And are the INTs documented anywhere?
If you'd like to boot DOS 2.11 (my recomendation) 128 K is sufficient
for DOS and most tools. It should be possible to strip it down to run
in as little as ~96 k, but below 64 K not even a complete boot is possible.
DOS 1.X is able to run in 64 K, although it will be hard to find programs
still able to run - after the introduction of DOS 2.0 everybody switched
for the new file I/O (Unix style, without FCBs).
CP/M 86 may be an alternativ way to go - way faster boot :)
Also, based on my experiance of a 8080 emulator I did on the KIM in 1979,
it will be hard to get a decent performance... I think the effective
speed on a C64 will be something like or below a 0.1 MHz 8086 (my 8080
emulation archived an equivalent of a 0.10-0.25 MHz 8080), depending on
the instruction mix of course
Say, wouldn't a Software CP/M system more aprobiate for a first step ?
Gruss
H.
--
VCF Europa 2.0 am 28./29. April 2001 in Muenchen
http://www.vintage.org/vcfe
http://www.homecomputer.de/vcfe
8:20 a.m.
New subject: H89 Computer For Sale - $10?
I'm selling my H89 computer. I built it but never used it much. Consequently, it is
really in mint condition. I've placed it on EBay with a starting bid of $10.
Here's a picture and more info if anyone is interested.
http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=352955051
The computer is located in Seattle.
Mark
9:26 a.m.
On Thu, Jun 08, 2000 at 05:25:00PM +0200, Hans Franke wrote:
If you'd like to boot DOS 2.11 (my recomendation)
128 K is sufficient
for DOS and most tools. It should be possible to strip it down to run
in as little as ~96 k, but below 64 K not even a complete boot is possible.
DOS 1.X is able to run in 64 K, although it will be hard to find programs
still able to run - after the introduction of DOS 2.0 everybody switched
for the new file I/O (Unix style, without FCBs).
FWIW, PC-DOS V2.0 runs OK in 64 KB. You can't fit much else in there with
it, but it does come up OK.
John Wilson
D Bit
10:55 a.m.
New subject: Z-Fest
Since it's only one month away, a small reminder for the anual
Z-Fest 2000
on Saturday, Sunday 8th and 9th of July in Gueglingen
(near Heilbronn, Germany). Two days of fun, among die
hard CP/M nerds. From old 8-Bit stuff to brand new
_superpowered_ Z280 systems in a cosy seting.
http://www.zfest.de/
Gruss
H.
--
VCF Europa 2.0 am 28./29. April 2001 in Muenchen
http://www.vintage.org/vcfe
http://www.homecomputer.de/vcfe
8815
days inactive
8815
days old
11 comments
7 participants
participants (7)
-
allisonp＠world.std.com -
ckaiser＠oa.ptloma.edu -
Hans.Franke＠mch20.sbs.de -
jbmcb＠hotmail.com -
mark.champion＠am.sony.com -
rivie＠teraglobal.com -
wilson＠dbit.dbit.com