Oh Master, tell us.. how did you defeat Spanky?

(For those who don't know what Spanky is, there now follows a brief description.
 This was written days before U8win was released.)

Ultima 8 is a DOS program.  Traditionally, DOS programs had a limit of 640K.
To get around this limit, you could either piss about with EMS and XMS memory,
or you could use a DOS extender,made popular by DOOM and company.
U8 came before DOOM, and so before DOS extenders were popular, and so it uses
a strange old 286 DOS extender. This I know for a fact because I had a look
inside it.

According to Jason Ely, ex-Origin engineer, Ultima 8 also uses 386 instructions
to speed up the graphics and various other tasks.  The problem with using 386
stuff in a 286 program like this is that when the DOS extender handles
interrupts,
for timing the game and also the sound system, the 16-bit extender only saves
half
of the 32-bit registers used by the game.

The net effect is that the game is happily doing something and then suddenly the
registers it was using get mashed for no obvious reason and it crashes.

To solve the problem, an evil piece of work called 'Spanky' was written by
John Watson and Tony Z. (See the U8 credits.. DOS extender kernel hacking)
But to preserve the registers it has to take complete control of the CPU, which
Windows obviously doesn't allow.

If you can disable SPANKY the game should naturally run, because the Windows DOS
extender will preserve registers correctly (or Windows would die itself).
Removing something as deeply embedded as SPANKY isn't going to be trivial.
The alternative is to do like U7run and emulate some of the CPU, but you would
have
to do MUCH more for U8.. you would also have to emulate the interrupt
controllers
too at the very least.

--
JP Morris - aka DOUG the Eagle (Dragon) -=UDIC=-  d...@it-he.org
Fun things to do with the Ultima games            (http://www.it-he.org)
Developing a U6/U7 clone                          (http://fly.to/ire)
d+++ e+ N+ T++ Om U1234!56!7'!S'!8!9!KA u++ uC+++ uF+++ uG---- uLB----
uA--- nC+ nR---- nH+++ nP++ nI nPT nS nT wM- wC- y a(YEAR - 1976)