Re: Ram disk --> Slot 7?

[dempson@atlantis.actrix.gen.nz (David Empson)]

In article <3hvuel$s27@cville-srv.wam.umd.edu>,
Geoff Weiss - The Doctor <iigs@wam.umd.edu> wrote:
> In article <2185.UUL1.3#25274@ace.com>, Luigi <luigi@ace.com> wrote:
> > Somebody else wrote:
> > >Sure you can, I have a RAM disk in slot 6. Of course, there just
> > >happens to be an Apple slinky card in slot 6.
> >A what?
> 
> A slinky RAM card is a RAM card that can go in slot 1 through slot 7
> (with the possible exception of slot 3, but that is another issue).
> The Typical AE RAM Card that goes in a peripheral slot fits in this
> category of RAM Cards.

That's the RamFactor.  Apple made the original card of this type
(Apple II Memory Expansion Card).  The PC Transporter uses the same
technique (the Apple device driver must be installed in the card to be
able to access it from the Apple side).

> GS/OS has a driver to make a RAM DISK out of this RAM Card.

That is the A2.RAMCARD driver.  It significantly increases the speed
at which the card is accessed.  Without the driver, GS/OS will
generate one anyway, but it will be slower.

> I have a PC Transporter in my slot 6.  Since I have the A2.RAMCard
> driver installed, I can use the RAM on the PCT as a GS/OS RAM disk.

I haven't had much success using the A2.RAMCARD driver with the PC
Transporter.  It gets a strange error at boot time (on entry to
Finder), claiming that there is a duplicate volume online.  I
investigated this a little and found out that something was causing
the first 256 bytes in block 2 of /RAMAEPC to be cleared.  This only
happened if A2.RAMCARD was installed.

> >Woah... what does that mean? What do I have to do do move it to another
> >slot? (How did you do it?) What is a "driver vector"?
> 
> Basically, there is a "device driver vector" in both GS/OS and ProDOS 8
> that tells the OS what disk device (and other items) are in which slot.

Not in GS/OS, only ProDOS-8.  GS/OS has a list of device drivers, and
each driver can support multiple drives.  There is a device
information block for each drive, which contains the slot and drive
number.  You cannot tell GS/OS to pretend a drive is in another
slot (you shouldn't need to do this).

> You would have to rewrite (i.e. make many patches) to make either OS
> think the /RAM5 (or even the /RAM for ProDOS8) is located in another
> slot and/or drive.

Actually, moving a drive to another slot in ProDOS-8 is reasonably
easy, in _some_ cases.  It depends on whether you are using ProDOS-8
1.9 or earlier, or 2.0 or later.  It also depends on the
implementation of the ProDOS block driver in the card's ROM.

If the ProDOS block driver ignores the slot number portion of the unit
number (bits 4 to 6), and only pays attention to the drive (bit 7),
then it should be possible to patch the device table to put the vector
in another slot.

With ProDOS-8 2.0 and later, SmartPort drives cannot be moved in this
fashion unless you patch the undocumented internal table that is used
by the SmartPort driver to remap unit numbers to SmartPort slot and
drive numbers.


I still don't know what the original poster is trying to achieve, and
on what computer.

Can he or she please elaborate on what they want to do, and why?
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand