Re: .DSK Image does not work on real machine, but, works fine in an Emulator

[Patrick Schaefer <patrick.schaefer@topmail.de>]

olcott schrieb:

> The problem is this file will not run on a real Apple IIe,
> but, does
> run on an Apple IIe emulator. How could a DSK work on
> an emulator, but, NOT, work on a real machine?

The logical sector numbers do not follow the physical ones, there ist an
interleave. DOS sector 1 is on physical sector 1, DOS 2 on phys. 7 and
so on. This gives the computer some time to process the data before the
next sector has moved towards the RW head.

DOS 3.3 and ProDOS use different interleaving schemes. 

ADT expects the disk images to be in DOS order, that means using the DOS
3.3 interleave. That means block 1 is written on physical sector 1, bloc
2 on 7 and so on. 

NuLib creates image files in ProDOS order. If you download a *.SDK image
and extract the *.dsk file, it won't work with ADT because the sectors
are scrambled. However, the emulator programs can recognize the image
format and therefore run both types. (They look at the catalog track)


Some time ago I have written a small TurboPascal program for PCs that
converts ProDOS order into DOS order. If you are interested, I can email
you a copy, or I can upload it to a ftp server (which - is
apple.cabi.net back?).


Patrick