Re: [hatari-devel] reading DMA sector count in HDC mode ?

[Thomas Huth <th.huth@xxxxxx>]

Am Sun, 15 Dec 2013 22:54:19 +0100
schrieb Nicolas Pomarède <npomarede@xxxxxxxxxxxx>:

> On 14/12/2013 10:13, Thomas Huth wrote:
....
> >> None of the doc I have are clear on this, they don't mention if
> >> sector count can be read or not. But as dma status has a bit to
> >> tell if sector count is 0 or not, this could confirm you can't
> >> read sector count, you can only know if it reached 0.
> >
> > I just had a look in my "Scheibenkleister" book (one of the best
> > books about Atari floppy and hard disks), and on page 179 I found
> > this statement:
> >
> >   "Leider kann man den Sektorzähler nur beschreiben, nicht aber
> > lesen; man kann nur an Bit 1 des DMA-Statusregisters ($FF8606, nur
> > lesbar) erkennen, ob der Sektorzähler mittlerweile bei Null
> > angekommen ist."
> >
> > Roughly translated:
> >
> >   "Unfortunately, you can only write to sector counter, but not
> > read it; you can only watch bit 1 of the DMA status register
> > ($FF8606, read only) to see whether the sector counter already
> > reached zero."
> >
> > Unfortunately, it is not mentioned whether there is a difference
> > between floppy and hard disk mode for the sector count register,
> > but I do not think that there is any.
> >
> 
> Thanks for this and for the translation (my german is a little rusty,
> so better having a verified translation :) ).
> 
> Byt the way, what it the name / publisher of this book ? In France, I 
> had many books from "Micro Application" which were considered as very 
> good reference books on HW. Most of them were translations of the
> german edition published by "Data Becker" (eg "Disquette et disque
> dur" ("floppy and harddrive") was my reference book for all wd1772
> coding).
> 
> Was your book publised by Data Becker ? If so, it seems some parts
> were not included in the translated french version.

No, sounds different, "Scheibenkleister" has been published by "Maxon"
instead. Actually, I hardly believe that this book has ever been
translated to another language, since it is written in a quite unusual
way for a non-fiction book: It is full of play on words and jokes that
are hardly translatable. This already starts with the title of the book:
"Scheibenkleister" - if you translate it literally, it means "disc
glue", but the colloquially meaning is rather an attenuated
swear-word :-) But beside being funny, it is still very detailed about
everything that is related to mass storage on the Atari ST, from
low-level MFM-coding to the high-level TOS functions, so it's really a
very useful book.

 Thomas