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Re: Apple II slot assignments
In article <4nbq6h$511@wraith.cs.uow.edu.au>,
David E A Wilson <david@wraith.cs.uow.edu.au> wrote:
> dempson@atlantis.actrix.gen.nz (David Empson) writes:
> >The rules applied by ProDOS-8 2.0 and later are as follows.
>
> >3. If there are any devices which support the "SmartPort" firmware
> > interface, and have more than two devices available, then ProDOS-8 will
> > remap them into unused slot/drive positions. For the purposes of this
> > remapping, only disk I/O devices (5.25" controller or cards with a ProDOS
> > driver) are considered.
>
> You missed step 2 and a half:
>
> 2.5. If a Smartport with more than 2 block devices is found in slot 5 then
> drive 3 will map to S2D1 while drive 4 (if present) will map to S2D2.
I thought that ProDOS-8 2.x didn't bother with that any more. I've
just checked, and it does. My mistake.
> > All of the remapped devices are handled by a driver provided within the
> > language card by ProDOS, which converts the ProDOS driver call into
> > a SmartPort call, and routes it to the appropriate slot.
>
> This is the case for all remapped drives except for those dealt with
> in step 2.5 as all Smartport cards that support > 2 drives must
> handle the slot 2 -> 5 remapping themselves.
Yep, and it is done by calling the ProDOS driver on the card, not the
SmartPort driver. The card must recognise a unit number of $20 or $A0
and remap it internally to refer to drive 3 or 4.
> The rules are fairly simple:
>
> a) Slot/Drives are used in the following order:
>
> S4D1, S4D2, S1D1, S1D2, S2D1, S2D2,
> S5D1, S5D2, S6D1, S6D2, S7D1, S7D2,
> S3D1
Ah! I thought it just started at slot 1. I have my SCSI card in slot
4, so I never encountered the remapping into slot 4.
It seems like a rather odd rule - why bother with a fixed remapping
order at all?
> b) If a slot has a block device controller in it then no devices can be
> mapped to unused drives for that slot. ie: a Slinky RAMcard has 1 drive
> but no other Smartport drive can be mapped to that slots drive 2 position.
Yep, I knew that one. I have two wasted unit numbers because I have a
SuperDrive controller with a single drive, and a PC Transporter (RAM
disk only). I can move one of my Apple 3.5 Drives to the SuperDrive
card if I get desparate (leaving one on the slot 5 firmware).
The only reason I can think of for this restriction is that it will
minimise problems with programs that try to identify devices by
decoding the driver address and examining the ROM.
--
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand