18 Nov
2007
18 Nov
'07
11:31 p.m.
On Sun, Nov 18, 2007 at 10:11:14PM +0000, Tony Duell wrote:
It's been a long time since I used one of these
'in anger' but wasn't
there an issue witch copying one of the random-access file types between
disks? (or maye between disks in different drive units). If I'm
rememebring correctly, it means the converting between 4040 and 8050
disks is a pain even if you haev both drive units .
My recollection is that in general, CBM DOS "relative" files weren't
particularly portable from DOS version to DOS version. I think you
had to understand the record structure and copy them one record at
a time. I think you might have been able to copy relative files from
one diskette to another in the same drive unit, but I never tried it,
so that's a faint memory and mere speculation.
Real "random-access" files weren't really supported under CBM DOS - games
like Zork that did do random access across the disc used their own
schemes and just marked the used blocks as unavailable to CBM DOS. Your
code just did block-reads and block-writes and ignored the directory track,
typically.
I did work a little with relative files with a C-64 and a 1541, but I think
that 99% of what I ran across were sequential files (executable code,
picture files, music files, source...) Those are easy to copy.
-ethan
--
Ethan Dicks, A-333-S Current South Pole Weather at 18-Nov-2007 at 23:20 Z
South Pole Station
PSC 468 Box 400 Temp -42.2 F (-41.2 C) Windchill -64.8 F (-53.8 C)
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Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html