vidpal - what and where
Brian D. Botton
botton at i88.isc.com
Wed Feb 28 16:14:39 AEST 1990
Hello again Unix-PCers,
Brad and I have been getting a @#$%$^() load of mail asking what is
vidpal and where to get it, so here it is once again. BTW, the current
port of Mgr requires the vidpal kit and unless someone writes a window
device driver that is significantly faster it will stay that way.
What is it?
Vidpal fakes the memory management unit in your 3B1/7300/S4 into thinking
its ok to write to video ram. Normally you get a bus error and a core dump
when you do this, but vidpal tells the system you are in kernel mode when
you access video memory. To do this, the SUPV signal off of the 68010 is
intercepted along with the address signals. When you address in the video
ram range a PAL asserts SUPV, telling the MMU to let you do what your heart
desires, otherwise SUPV is left untouched. Because the address signals are
monitored, only the video ram is made accessable to user level programs.
Since user level code can manipulate the video ram, you don't have to write
a device driver, like wind.o, for each window manager you want to port, like
Mgr or X.
In order to intercept the signals a little daughter board has to be inserted
between the 68010 and the mother board. This method was used because it
DOESN'T require ANY modifications to the mother board so you don't have to
worry about messing anything up.
To make things easier I am selling a partial kit, I stopped selling full kits
because it was too much work keeping parts in stock. It may seem trivial, but
I have purchased over $1200 in parts in the last 6 months just for vidpal kits!
Anyway, the kit includes the three most difficult parts to optain, a PC board
with solder mask, a programmed PAL, and complete instructions, including part
numbers and source for the rest of the required parts. Cost of the partial
kit is $10 and the additional parts are in the $15 range from Newark
Electronics.
Where do you get one of these babies?
Send a check for $10 made out to me and a return mailing label to the
following address:
Brian D. Botton
4715 Old Oaks Dr. #3B
Lisle, IL. 60532
I plan on providing these kits for the foreseeable future, so you don't have
to worry about support disappearing.
I am also providing the P5.1 upgrade kit that allows you to access more than
eight heads on a disk drive. The kit inludes a PAL, socket, capacitor, and
complete instructions. You will need to get a WD2010? elsewhere to get more
than 1024 cyclinders. Also, if you don't have the extended diagnostics disk,
you will need one in order to format your drive correctly. Below is a price
list for all of my kits.
P5.1 kit only $6
P5.1 + extended diagnostics disk $7
extended diagnostics disk only $2
vidpal partial kit $10
NOTE: Lenny and Gil (ICUS Software) sell a kit that allows access to two hard
drives and also provides the functionallity of the P5.1 mod. While the P5.1
doesn't hurt anything, it is a no-op when you use their kit.
As always, feel free to send me questions about the vidpal or P5.1 kits.
If you have a question about Mgr, you should pass them on to Brad. Mgr is
available via anonymous ftp.
Brian
--
... ___ ***
_][_n_n___i_i ________ ******* Brian D. Botton
(____________I_I______I_I_______I laidbak!botton or
/ooOOOO OOOOoo oo oooo oo oo laidbak!bilbo!brian
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