RAW Read on PC

How can I read the entire track along with the “marking”
(index arrays) on a PC-based FDD? The commands “read track” and “read cylinder”
(there is one - it is used, for example, by the DiskDup program) are not suitable -
they read only the contents of sectors. It is not suitable to use non-standard controller commands (CopyLock-protected 1C: Accounting works on any hardware!). Nevertheless, a number of programs do this in an elementary way. This applies not only to the Fryazino FDA files, but also to such a wonderful program as UKV Spectrum Debugger v1.0.
And it does it quite carefully, so that many
protected programs work. For example, the branded version of “Star Heritage”,
protected (as is known) by the Rybinsk MicroProtector - simply
works under UKV...
But in order to read the key mark at the end of the track, a
"raw" reading is done...

Well, now, closer to the point...
To get the entire image of the track on a PC they do the following: they read the first sector following the index hole, but do this in a cunning way... For a double-density floppy disk, the length of this sector is declared to be 8 kB. As a result, the entire track ends up in the buffer, and with an overlap... The controller returns a CRC error code for this "sector",
but thisno longer matters (in the VG-93 this procedure also occurs without control).
The only caveat is that on a real Speccy the buffer begins
with GAP5 data (from the beginning of the index pulse), and on a PC - with the data of the first
sector. Therefore, in order for everything to be correct, it is necessary to analyze
the “overlap” and make the appropriate offset (so that the label is in the
required “place”)!

The fact that the iNTEL controller does not have a “raw” read command
proves the fact that the FDA cannot obtain an image
of a track on an unformatted disk, although VG-93 does this without straining...
At the same time, the authors of the FDA write in the accompanying documentation that
when writing the program they used undocumented capabilities of the
controller (???)

Well, that's ALL !!!

Crack-Band "Black Cat". Chelyabinsk 1997