13 Apr
2012
13 Apr
'12
7:08 p.m.
On 04/13/2012 04:43 PM, Fred Cisin wrote:
I suspected that might be the case, although I didn't realize there was
quite *that* much variety...
Yes, several different releases, but also various other tools, utilities,
public domain disks, and a couple of games. The games disks seem to have
some form of copy protection such that Imagedisk chokes on them (they work
OK on the system itself), but everything else read OK[1]. I just want to
check that they are what they claim to be (and haven't been overwritten
with e.g. previous owner's financial records!) before I upload them somewhere.
[1] Although I have a neat little pile of hub rings sitting on the desk
next to me; they were falling off every single one of the PD disks. I don't
know how common others have found that, but it's been a *long* time since
I've seen a hub ring failure (sadly there's no vendor information on the
disks, so I don't know who made them).
Well, it was just a thought that it it was virtually no effort to make
things quite generic, I may as well. I think cpmtools claims a directory
entry limit of 128 for the QX-10, which is comfortably within the 512x10
track format of all the disks that I seem to have, but it wouldn't be much
work to iterate across multiple tracks for a more flexible reader.
cheers
Jules
On Fri, 13 Apr 2012, Jules Richardson wrote:
Thanks - yes, I do, so will give that a try...
Is there any kind of sensible maximum limit for
the number of directory
entries that a CP/M disk may contain? Or did every vendor just do their own
thing (probably!) and it's preferable to just keep parsing from the start
of the directory area until either the end of the media is reached, or a
location identified as file data by a previous entry is encountered?
Do you have access to a working machine?
STAT DSK:
will display that information. And, related
to that, if the directory area of a CP/M disk spans multiple
tracks, was there a standard for whether it iterated head-first (in the
event of media with multiple heads) or cylinder-first? Or does code have to
cope with both possibilities?
Yes, there were standards.
Standard 1: iterate head first, each side is a track (slightly faster)
... I'm just
pulling some data off some QX-10 floppies
"Valdocs"? (none of which
seem to
take up more than a track for the directory area), but it seems like a good
idea to make it as generic as possible.
If you are dealing with multiple different formats (and QX-10 had
several), number-of-blocks of DIRectory is one of your variables.
Are you planning to make your code general for formats besides Epson QX10?