Extracting CDOS and CP/M) files - Progress

[Dave Dunfield]

Ok - this morning I got a program working which can extract the
CDOS files directly from my ImageDisk images - The extracted files
exactly match two other sets extracted independantly for me by
Mike S. and Chuck G. (THANKS guys!) - so it looks like I have it
working correctly - this makes things much easier, since IMD is
able to read the disks with no problems - since I'm planning to
provide both IMD backup images of the disks, and ZIP files
containing the content files, this will save me a step as well.

When I have time, I will look into enhancing the utility into a
general purpose tool for reading and writing files to CP/M images.
You will need to provide some additional information so that
it can know how to access the particular image. So far I have
needed:

- Cylinder/Head mapping and interleave required to access CP/M
  logical sectors.

- Actual size of a physical sector (I can get this from the .IMD)

- Number of 128 byte records in a cluster (Yeah, I know you guys
  call them blocks, however CDOS refers to them as clusters).

- Number of directory entries.

- Offset to user area (size of system area).

- I'll need to add something to handle 16-bit allocation entries
  etc. when I move on to "large" disks.

Not all of this information can be gleaned from the disk, so a
general tool will need some sort of configuration file similar
to what Chuck does with 22disk.

Will let you know if/when I get "a round tuit" - at least now
I am able to extract the files from the diskettes with relative
ease.

Dave

--
dave06a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: www.dunfield.com
com             Collector of vintage computing equipment:
                http://www.classiccmp.org/dunfield/index.html