Re: ADT with 3.2/3.3 software switch program?

[pausch@saaf.se (Paul Schlyter)]

In article <438d8e9f$0$27889$9b4e6d93@newsread4.arcor-online.net>,
Linards Ticmanis  <ticmanis@gmx.de> wrote:

> Lyrical Nanoha wrote:
>> I've had a disk image from some time ago that features a program called 
>> "DUBBELDOS" which was written by Paul Schlyter, it allows DOS 3.2 disks 
>> to be read from DOS 3.3 (and seems to work with ESDOS too), I'm 
>> wondering if something like ADT13 would be compatible with something 
>> like this.  (I don't have the setup to test this atm.)
> 
> Yes and no. I haven't tested it but I'd assume that ADT13 would run with 
> it, provided that Dubbledos allows reading *and* writing of 13-sector 
> disks with standard RWTS calls.

It does.  DUBBELDOS adjusts itself to 16- och 13-sector reads/writes
on-the-fly: it remembers its current mode (13-sector or 16-sector)
and when the RWTS is called to read or write a sector, it tries to
find an address mark: if in 16-sector mode, it looks for 16-sector
marks, and if in 13-sector mode it looks for 13-sector marks.  If it
fails to fins such a mark, it looks for address marks of the "other
kind": if found, it switches mode (and beeps to indicate a mode
switch).  If it fails to find an address mark of the "other kind"
too, the RWTS exist with an I/O error, without switching mode.

When the address mark is successfully found, the DUBBELDOS RWTS goes
on reading or writing the sector, according to the current mode
(16-sector or 13-sector).

> But Dubbledos removes the INIT code from DOS,

Yep - that space was needed to store the code for reading and writing
sectors on 13-sector disks.  The actual code was picked from DOS 3.2
of course.

> so you can't use it to format 13-sector disks, and ADT13 requires 
> formatted disks, just like all the other versions of ADT.

The process will then be:

1. Boot DOS 3.2 and format the 13-sector disks as you need.

2. Boot DUBBELDOS, and run ADT13 on it to transfer disk images
to 13-sector disks.

ADT (both the 13-sector and 16-sector varieties) need disks which
already are formatted.  There's no way to format the disks from
within ADT.

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