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Re: Seagate ST255N [20 Meg SCSI] Wanted
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In article <080720042021406291%jonrelay@napanet.net>,
Jonathyn Bet'nct <jonrelay@napanet.net> wrote:
>I don't know about GS/OS, but I know ProDOS keeps track of everything
>in terms of blocks, and the fields for storing block numbers are all
>16-bit integers, allowing only 65536 blocks, or 32768K, or 32MB maximum
>for anything. Trying to increase the size of a block is only going to
>send every existing Apple II program crashing down on us.
I would think that most apps wouldn't be bothered by an increase in block
size, since most apps don't do block-level access. Theoretically, you could
come up with a completely different filesystem with a much higher limit for
size and write some code to intercept ProDOS MLI calls. In practice, I
suspect this is how network support was added by Apple back in the day.
Those apps that do block-level work would choke on such an extended
filesystem, but the only apps that should do that type of access are
filesystem utilities (defraggers, undeleters, and such) that would need to
be replaced anyway.
>(In addition, ProDOS stores the size of a file in a 24-bit integer,
>limiting the total size of a file to only 16MB.)
This could be a problem, but I'm not aware of much software for the II that
would handle larger files. The AFP clients provided by Apple for the IIe
and IIGS already deal with >16MB files somehow, so you could start with what
they did and go from there. I'm guessing that either (1) large files are
inaccessible under ProDOS 8 or (2) only the first 16MB of large files can be
accessed...though it seems that streaming read/write activity should work
indefinitely, so maybe neither of those are the case.
_/_
/ v \ Scott Alfter (remove the obvious to send mail)
(IIGS( http://alfter.us/ Top-posting!
\_^_/ rm -rf /bin/laden >What's the most annoying thing on Usenet?
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