TOS max 14 partitions (logical drives) limit

[ParanoidLittleMan]

Sorry it this is complicated, but I'm sure those with some experience with mass storage on Ataris will understand most of written.

 

It is known that TOS can handle max 14 hard disk partitions (logical drives) in range C-P . That should be enough for normal usage, but there are cases when more would be welcome - I guess in first place when you have 2 cards inserted in UltraSatan, and total count of partitions is over 14. My driver SW will ignore partitions over P, and that's good, because attempt to access them will cause crash, may be even danger of data corruption. They should really add simple code what ignores all such attempts totally.
I looked about that limit in TOS code: things are that there is simply no space provided in GEMDOS workspace for more partitions. If try to access partition over P, it will destroy some variables, what may have unpredictable (harmful) effect . Solution would be to add more space, of course . But that will break complete RAM usage of AES then, and of course decrease available RAM for SW. I'm really disappointed again, how this problem is neglected by Atari .
Thinking about some reasonable solution .. Since nobody will need all, let's say 25 partitions on 2 cards at once, solution would be to let user to select those which needs in that session, max 14, of course. Something like:
Select active partitions, max 14 totally:
Physical order on cards.
Card 1: C, D, E, F, G, H, I, J, K. L. M, N, O, P
Card 2: C, D, E, F, G, H, I, J .
I use C as start by both just because it is easier so to know what partition on concrete card is it . When it will be mounted, letters for partitions from second card will start not with C, but first letter after last active part. of card 1. That will allow file transfers too.

In case of using 2 diverse driver SW, for instance when there is 1 IDE and some ACSI drive used at once, this can work too, but little different:
Only with direct runnable driver versions: Let's say that first driver mounts 14 partitions, and we want some data exchange. Then second driver SW must open same selection dialog, and then it will actually deactivate non-selected partitions from first media. That's easy to achieve - Hddriver does it with all of them, without question, btw.

Considering age of machines, it is wise to use only 1 storage media at once in normal work. That means 8 GB card well utilized (except old TOS versions like 1.00-1.02) . So, I really don't see need to go on more than 14 partitions. With improved FAT16 it can be 16 GB, because max part. size is 1 GB .

Edited June 21, 2018 by ParanoidLittleMan

[+SoulBuster]

I was wondering why someone needed more than 14 partitions active at one time in the other thread. I use HDDriver and it can change active partitions easily.

 

I have a 32gig PATA SSD installed on my Falcon. It is split up into 32 1 gig partitions.

 

I keep a small number of partitions active 5-7. The others are used to store archive material on. I swap in one of those partitions just long enough to store something on it and swap it back out.

 

I do not see a reason for more that 14 partitions active at one time, in fact, it could even be less, in my opinion.

[ParanoidLittleMan]

I don't know how it is solved in Seimet Hddriver, did not see it in older versions, did not see newer versions . My target users are mostly TOS users.

 

Active partition selection dialog should look like:

It will appear always when total partition count is over 14 - then user can select which will be active. Column SEL shows what drive letter it will be.
There may be some special keys for 'select all' - then will actually select only first media partitions. Only second media ... Load preconfigured .
If there is no more than 14, dialog may appear by some keypress too, then may discard some partitions - so will mount only some, which user want to access.
And of course, option to swap C partition with any higher will be still there - only that it will be not with physical ones, but selected ones.

[ParanoidLittleMan]

And more work, tracing, code fixing - managed to make it work with 30 partitions - C-Z and 6 more (special characters) .

This will be best usable with Desktop of 2.06 :