💾 Archived View for mirrors.apple2.org.za › archive › ground.icaen.uiowa.edu › MiscInfo › Prodos › v… captured on 2023-01-29 at 10:12:18.

View Raw

More Information

-=-=-=-=-=-=-


Robert Steinmetz <not-rsteinmetz@mindspring.com> writes:
>I understand that Prodos limits the number of volumes to 14, 2 
>for each slot and that there is an allocation scheme so that if 
>you have more the 2 volumes on one device these will be assigned 
>to unused slots.

>Can someone please explain the rules for allocation of slot and 
>drive numbers to additional volumes and under what versions of 
>ProDOS or ROMs these rules operate.

OK. If you look at ProDOS Technote #23 it describes the changes made
to ProDOS from version 1.0 to 2.0.3 (provided you find a recent version).
You can divide ProDOS 8 into 3 groups based on how it handles volumes.

A) ProDOS v1.0 to v1.1.1 - two drives per slot
B) ProDOS 8 v1.2 to v1.9 - two drives per slot except that slot 5 can have
   4 volumes if slot 2 does not have a disk controller card in it.
   The 3rd volume becomes S2,D1 and the 4th S2,D2. This remapping relies
   on the disk controller firmware knowing what to do when passed a unit
   number for slot 2 when it is in slot 5 - any controller supporting more
   than two volumes must support this.
C) ProDOS 8 v2.0.x - up to 13 volumes on a SmartPort capable disk controller
   (/RAM takes up 14th position S3,D2)

Note that the V2.0.x remapping can only use vacant slots - if you had a 1MB
memory expansion card in slot 4 which is a single volume (S4,D1) the remapping
code will not use the vacant S4,D2 for a drive from another slot. There is
a defined order that v2.0.x will allocate vacant slots based on a table in
the PRODOS file (list taken from v2.0.3):

S4,D1 S4,D2 S1,D1 S1,D2 S2,D1 S2,D2 S5,D1 S5,D2 S6,D1 S6,D2 S7,D1 S7,D2 S3,D1
-- 
David Wilson  School of IT & CS, Uni of Wollongong, Australia



David Wilson wrote:
> 
> OK. If you look at ProDOS Technote #23 it describes the changes made
> to ProDOS from version 1.0 to 2.0.3 (provided you find a recent version).
> You can divide ProDOS 8 into 3 groups based on how it handles volumes.
> 
> A) ProDOS v1.0 to v1.1.1 - two drives per slot
> B) ProDOS 8 v1.2 to v1.9 - two drives per slot except that slot 5 can have
>    4 volumes if slot 2 does not have a disk controller card in it.
>    The 3rd volume becomes S2,D1 and the 4th S2,D2. This remapping relies
>    on the disk controller firmware knowing what to do when passed a unit
>    number for slot 2 when it is in slot 5 - any controller supporting more
>    than two volumes must support this.
> C) ProDOS 8 v2.0.x - up to 13 volumes on a SmartPort capable disk controller
>    (/RAM takes up 14th position S3,D2)
> 
> Note that the V2.0.x remapping can only use vacant slots - if you had a 1MB
> memory expansion card in slot 4 which is a single volume (S4,D1) the remapping
> code will not use the vacant S4,D2 for a drive from another slot. There is
> a defined order that v2.0.x will allocate vacant slots based on a table in
> the PRODOS file (list taken from v2.0.3):
> 
> S4,D1 S4,D2 S1,D1 S1,D2 S2,D1 S2,D2 S5,D1 S5,D2 S6,D1 S6,D2 S7,D1 S7,D2 S3,D1

Thanks for the quick response. I understand the order much 
better now and think I know what to expect. I need to put ProDOS 
2x on a floppy, which is easier said than done with my hardware 
setup. I think I going to enable a dial-in port on a server at 
the office to allow this to happen, although I also have a copy 
of crossworks with a cable here somewhere.

I assume that ProDOS 2.x uses the actual slots first and the 
begins using predefined list, skipping any slots already used.

For example in my card with 8 drives in Slot 7 and RAM in Slot 5 
would expect to see;

S7D1	Volume1
S7D2	Volume2
S6D1	Floppy Drive 1
S6D2	Floppy Drive 2
S5D1	Ram Drive
S5D2	<unused>
S4D1	Volume3
S4D2	Volume4
S3D1	<unused>
S3D2	RAM
S2D1	Volume7
S2D2	Volume8
S1D1	Volume5
S1D2	Volume6

I read that the slot does not have to be vacant but only not 
occupied by a block device, and that slots containing some types 
of cards like serial cards and mouse cards can be remaped also.

-- 
Rob

"Never ascribe to malice that which can adequately be explained 
by stupidity."