Source:GEnieLamp A2, December 1995

From Eamon Wiki
Jump to navigation Jump to search
This page is a verbatim reproduction of original source material and should not be edited except for maintenance.

Section excerpted from the December 1995 issue of GEnieLamp A2.


No source specified. Please edit this description and provide a source.


December 1995


No author specified. Please edit this description and credit the creator of this work.


It is believed that the use of this copyrighted item in Eamon Wiki qualifies as fair use under the copyright law of the United States.

Previous item

Source:GEnieLamp A2, November 1995

Next item

Source:GEnieLamp A2, January 1996

A2 Pot-pourri

What's a .DSK file?

Does anyone know what a .DSK file would be? A friend found a bunch of Eamons on an Internet ftp site, and they have that suffix. He can't figure out how to use them. ShrinkIt says it's not an archive.

(A2.TOMZ, CAT10, TOP10, MSG:27/M645;1)

>>>>> That is a "disk image" file, representing an Apple 5.25" disk, 16 sector, as follows:

1'st 256 bytes = Track 0, Sector 0
2'nd 256 bytes = Track 0, Sector 1
3'rd 256 bytes = Track 0, Sector 2

The common formats are:

.DSK – As described above
.DO – Same as .DSK. (Note that these two formats have the data in "DOS 3.3 ascending logical sector order", data should be handled as sectors, and not as ProDOS blocks)
.PO – This is essentially the same as .DO, except that it is in "ProDOS ascending block order". That is, it was created by reading a 16 sector disk with the ProDOS ReadBlock command, and is ordered Block 0, Block 1, Block 2, etc.

Conversion between .DO/.DSK and .PO formats is relativly trivial, once one understands the differences.

Most files of this nature are stored as "Name.DSK.GZ" or "Name.DO.GZ", etc. You need a utility capable of unGZipping these archives prior to trying to write them back to 5.25" media. I have had very limited success using GZ2PKZ followed with Angel or PMPUnZip, and almost 100% success with StuffIt Expander w/Expander Enhancer. [I now have the source code for a GZ unpacker, but I haven't yet tried to port it to the GS]

These files are how Apple II emulators manage to deal with Apple disks without the needed hardware (they don't use a real drive, instead they work with virtual disks)

(HAROLD.H, CAT10, TOP10, MSG:30/M645;1)
[Minor editing at author's request]