RE: 1541IDE and 1541IDE-S -- and 8250IDE? (and 64IDE, now)

ruud.baltissen_at_abp.nl
Date: 2007-12-27 08:34:01

Hallo Matt,
 

> i think you need to sync the pc to these times??

Not at all. These timings only exists so the drive can make optimal use
of the storage of a track. The PC doesn't do this at all: it just dumps
9 sectors of 512 bytes on every track (360 KB version). Some programs
abuse these timings as a kind of copy protection: they rewrite some
parts of the disk with another speed then the original one. If read 


> anyway if i send someone this book can they scan it to pdf???

No problem. But realise that, having a sheetfeeder, I'll have to cut the
back of the book. If interested, send me a PM.



Hallo allemaal,


I found some time to test IDE1.ASM and it partly works. Partly because I
have a very strange error and I haven't found the cause yet. At
http://www.baltissen.org/files/ide1.asm you'll find the sources. When
formatting the disk, the stored ID is replaced by zeros. I solved this
problem by replacing the ID with pre-programmed values; just look foor "
lda #'R'" in the source. 40 lines above you'll find the marker @@10. At
this point things are fine. So somewhere in these 40 lines is a
subroutines that causes the trouble. The funny thing is that I can save
and load a file W/O any trouble. But when trying to format the disk for
the second time, the process ends up with a writing error on track 18,
sector 0. When checking, things look allright. I have the idea that
whatever changes the stored ID, also changes other Zeropage values,
causing the "compare aftre writing" routine to go wrong. 
My idea for the moment: I use X or Y in a subroutine W/O checking if it
holds a value needed for other routines.

The only tool I have at the moment is my so called POSTcode display: two
intelligent 7-segments display connected to the free A-port. This
enables me to have a look at certain values but a far from ideal tool.


I need some help with a very weird behavior. At marker &&&12 you'll find
the subroutine FormatTrack. Somewhere down you'll find the line ";
cli". The weird thing is that when I remove the semicolon and thus give
the command to enable interrupts, the drive won't change tracks any
more. Changing tracks is done by the Interrupt routine so I can imagine
that SEI without CLI would cause this problem, but no, only CLI does.
Anyone has an idea?


As you can see, I'm at work. But next week I have a week oof, thus more
time to work on the project :)


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   / /  |_/     Groetjes, Ruud
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