emulatorII-list

Hi again,

the speed is 300 rpm, selected in PC by the density line. Try to
isolate pin no 2 of the bus connector in your PCs TEAC drive and set
'I' and 'LG' on the drive to make it spin at 300 always.

For the overlays, as I could see until now, they definitely start
after Track 0/Head 1. I think Track 0/0+1 is loading some small
overlay to determine the handling of Preset- and Librarydisks. At
least it looks like from the code (MAIN) which is only loading this
track from disk. Any other steps of the head position on the disk can
not be found in the main code (or I missed a branch). Beginning of the
MAIN code is for Init, including 'self-test', which is only a check
for the correct response on the IN ports (better say their values
written to static RAM from 2000H after Memory has been initialized)
within a specified time. Some small part is for handling Memory
Controller Init and most of the rest is handling the disk and checking
for several error states.

Notice that this disk control only starts after inserting a disk,
without, it loops around 09C2 (with the string "Insert Diskette"),
during which it is straight checking a bit at a memory offset not yet
known. It seems to be the same offset(s) used during the 'self-test',
so in fact the initial drive 'self-test' is only a check for 'a piece
of metal on a strap'.

Just at the moment, I'm working out this address which I suppose
resides in the static memory, mapped from I/O area (or just one of its
pins as for the bitcheck) of the SIO, and the ports for the SIO, which
I suppose is on port 30H and 31H, as these are the only ports accessed
with DI (disable interrupt) set. 

If you try to read out Track 0 as a sequence only, without looking for
any format, it could show some data. I can't say anything about the
EII disk timing, so try increasing ticks after the index hole trigger.

And, does anybody have a catweasel MK4 which I could buy? They seem to
be sold out (again)...

Greetings,
Hoschi

--- In emulatorII-list@yahoogroups.com, "esynthesist"
<esynthesist@...> wrote:
>
> Hi there,
> 
> The EII formats the floppy disks with 2 sides of 80 tracks, each 
> having 3584 bytes (probably one big sector).
> This is 560K on a disk on which DOS only formatted 360K. 
> It's pretty sure that this massive capacity is only possible by NOT 
> putting physical header/gap zones between sectors (of e.g. 512K) and 
> that may be the reason why a PC can not read them.
> 
> These disks hold both the OS and the soundbank. The 476K of sounddata 
> are written sequentially on the disk immediately after the OS area, 
> and has exactly the same layout as the SoundDesigner for Emulator II 
> files. So if you want this part of the disk, just unload them with SD 
> on a Mac. 
> If you want to get the OS part, you'll need to find a way to read the 
> disks on a PC...
> ...something no one ever succeeded in the last 20 years.
> 
> This is due to this softsectored 3584 byte tracks, which is not a 
> sectorsize known by a PC floppycontroller.
> Another issue may be the rotation speed of the drive, which may be 
> different from a PC's drive (controller command). Although I'm not 
> sure about this, because I haven't heard yet of two different speeds 
> available in 5.25 drives - I think they were all 360rpm. But it's a 
> known problem with some 3.5 drives (e.g. the CASIO FZ series suffers 
> from this problem). Anyway, the Catweasel controller is capable of 
> different speeds, so that may be a solution if the problem really 
> exists. 
> 
> I have also tried to read EII disks on my PC's (with 5.25 drives) but 
> was unsuccessful until now. But I was planning to do some new 
> experiments in the near future... only because of the challenge since 
> SDII is for sure a much better way to keep an archive then reading 
> the floppies !
> 
> Good luck
> 
> ///E-Synthesist
> 
>   
>