Re: :( 12 Partition Limit!?!?!??? :(

[johnlb@primenet.com (John Bowling)]

In article <4rn97o$e2i@atlantis.atlantis.actrix.gen.nz>,
David Empson <dempson@atlantis.actrix.gen.nz> wrote:
>In article <C070496234857.5760@darkcastle.ecore.fnet.org>,
>Dark_Dude <Dark_Dude@darkcastle.ecore.fnet.org> wrote:
>> 
>> In Article <31DB7CDD.15CC@rmci.net>,
>> <Mikeal@rmci.net> wrote:
>> 
>> >Why can't someone redo the SCSI card for the Apple //'s in such a
>> >way that it will use the fullness of some of these new drives, 720 meg, 1
>> >gig, 1.5 gig, etc. And be able to go beyond the 12 partitions limit.
>> 
>> I remember Jan Maes telling me that you could have more than 14 partitions,
>> 110 max. but they were the sum of several scsi devices. I don't recall how
>> that worked...
>
>The Apple High-Speed SCSI card has an internal limit of 110 partitions
>(I thought it was 111) in total, spread over all connected hard drives.

<Snipped some good info>

>The best method of handling a large hard drive would be for someone to
>write a utility that patches ProDOS's internal tables to select between
>arbitrary 32MB partitions on a large hard drive (or drives).  You
>could then remap any ProDOS partition to any unused ProDOS unit number
>(probably still excluding real devices, to avoid confusing software
>that tries to work out what device it is talking to).

I can see another problem when you are trying to write out a file that
fills the partition and then need to use part of the next one.  The
next block address would put you back to some place in the current 
partition (probably in the middle of another file).  It would take some
extra manipulation to find out where the continuation of the file is.

Defragmenting could be a real nightmare!

It would be best if the FST would look at the size of the file and the
space remaining on the disk and then jump to the next partition if
needed to keep the file on one partition.  And there are times when the
size of the file is unknown.  An example is while editing and you have
saved when partially completed, and then go to save needing more space
than is available.  This would require that the current file be deleted
before the next one is saved.  I suspect most editors simply write the
current data out to an already open file, and the new process must
work with all existing software.

>David Empson
>dempson@actrix.gen.nz
>Snail mail: P.O. Box 27-103, Wellington, New Zealand

John


--
--==--==--==--==--==--==--==--==--==--==--==--==--==--==--==--==--==--
- John Bowling          -- Did anyone notice the recent switch by the
- johnlb@primenet.com   -- southern baptists to become anti-christians?
--==--==--==--==--==--==--==--==--==--==--==--==--==--==--==--==--==--