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Old 15 January 2010, 13:25   #12
Amiga Games Database
Angus's Avatar
Join Date: Jun 2006
Location: South West England
Posts: 534
Originally Posted by Peilton View Post
Hi everybody and please don't shoot me. The answers to my questions are certainly to be found here or easily on the net but I wanted to ask the professionals here about Amiga formats with some explanations if possible.

Feel free to treat me as the biggest noob ever and thanks in advance for your help on this.

I can't match the previous posters' technical knowledge but in case it helps here is a basic, practical description.

If you had an Amiga game that only worked from a floppy and you wanted to e-mail it to a friend, you might adf or dms it - and then save the resulting .adf or .dms file to attach to your e-mail. My (limited) understanding of these programs is that they create an exact disk image of the floppy, so that when it is written back to a floppy, the data will be written to exactly the same locations as on the original floppy, which is crucial for some software. Note - these programs are not designed to be able to make copies of protected floppies.

(a bit of a background example)
The WHDLoad guys, when they work their magic to make old Amiga games run from hard drive and compatible with newer machines, sometimes break the game down into its original files, and sometimes use disk images. The disk images will often be called disk.1 disk.2 etc but they are probably just .adf files that could (if you wanted to) be written back to floppy. The patchers (cunning chaps that they are) write a special slave file for the game that enables it to run from you hard drive.

If you had some files to e-mail to a friend - maybe pictures or audio or a game that wasn't reliant on being run from floppy, you could use a program like Lha to compress them into a single .lha file that your friend could then decompress with Lha or a compatible program. I've found it quite useful just as a way of bundling a few files together into a single file regardless of how effective the compression, as its more convenient just e-mailing one large file than lots of little ones.

Note - programs like Lha obviously restore the archived file to its exact original form when it is decompressed. Its not like JPEG compression that uses "lossy" compression where it sheds data from an image to reduce file size at the cost of quality - that would be fatal for a computer program.
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