Dealing with Diskcopy
Recent uploads of Mac diskcopy images to Asimov
have stirred interest in how this
format can be dealt with by real Apple II and Apple II emu users.
1- How come the files end with ".dsk"? Isn't that supposed
to mean the file is
a regular emulator disk image?
Yes; however, the ".dsk" suffix is sometimes
used for diskcopy images. Diskcopy
image names may also end with ".img", ".image", and ".dimg". Since the Mac OS does
not much care what a file is named, a diskcopy image uploaded from a Mac may have
nearly any suffix or none.
2- How can I know that a file is an 800k diskcopy image.
Often, the uploader will include a Text file
telling about the upload and mentioning
that it is a diskcopy image. Another way to be fairly sure that you are dealing with an
800k diskcopy image is to check file length. 838,484 bytes seems to be the usual
length of diskcopy images of Apple II 800k disks.
3- The emulator I use wants .2mg files, not diskcopy. How can
I convert a
diskcopy image to .2mg format?
Diskcopy images of Apple II disks seem, fairly
consistently, to be diskcopy v4.2
images. On PC, these can be converted to .2mg images using an XGS utility named
"imgutnew.exe" (for "image utility new"). It works well for converting the 202 Alliance
diskcopy (".dsk") files originally uploaded to Asimov. You can get the utility from the
XGS FAQs site and several others. For download links, see the File Utility FAQs.
4- How can I get a diskcopy image to diskette on my Apple IIgs
The most direct way is to transfer the diskcopy
image to the GS and use Clone
or Diskcopy to convert the file to diskette. For Clone and Diskcopy download links
check out the File Utility FAQs.
An alternative is to use the XGS image utility
mentioned earlier to convert the
diskcopy image to .2mg format on your PC. Transfer the .2mg file to the GS. On the
GS, use ASIMOV v2 or DSK2FILE v5.5 or higher to convert the .2mg file to
diskette. On an 8-bit Apple II ("128k", with 3.5" drives) you can use DSK2FILE.
For ASIMOV v2 and DSK2FILE v5.7 download links, see the File Utility FAQs.
5- I converted a diskcopy image to .2mg. Unfortunately, the
.2mg file shows up
as 819,264 bytes long on my PC. How can I NULL modem transfer the file to
a 3.5" 800k diskette on my Apple II?
Most .2mg files contain several blocks of zeroes
and will take up less than
800k on a ProDOS diskette. The main problem in a NULL modem transfer
would be with Z-modem or any other protocol that sends length information
before sending a file. The receiving program (on the Apple II) may break off the
transfer because the target diskette seems too small to hold the file. Using a
dumber protocol (e.g. X-modem) should let the transfer go through.