Choosing between three Sony MPF-920 drives

Update your old 720k to a 1.44 drive etc.
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exxos
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Re: Choosing between three Sony MPF-920 drives

Post by exxos » Sat Oct 21, 2017 12:53 pm

The only thing the switch can do is set WP low so that TOS will "probably" re-read the FAT. The drive cannot spin up or read things on its own.

TOS sends the commands to the 1772 to spin up, TOS also sends the command to read track 0. All the drive can do is "try" to inform TOS that the disk might have changed so TOS will re-read the FAT.

IIRC this behaviour various across TOS versions, its possible like TOS1.00 doesn't work regardless of what is done. I never checked.

You should use the program I wrote to see the status of what TOS sees.
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Re: Choosing between three Sony MPF-920 drives

Post by Pacman » Sat Oct 21, 2017 1:42 pm

I've tried your Media check program but didn't quite understand how to use it (yes, I've read the docs on the above page). Do you insert/remove floppy disks and see what the message is or does it simply "analyse" the drive once to determine the type of disk detect mechanism used? Also I could never figure out how to quit (neither the most obvious Q, CTRL-Q, ALT Q or ESC worked). It flashes "disk may have changed!!!" here by the way. That's with the CTIN switch shorted.

So did my checking reveal anything new?
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Re: Choosing between three Sony MPF-920 drives

Post by exxos » Sat Oct 21, 2017 6:38 pm

There likely isn't a quit, it was wrote in a hurry and only for a quick indication, it wasnt intended as a full app by any means.

TOS will say "might have changed" if it detects WP going low. If it does not, the message will read "not changed" or something like that, I don't remember all the messages exactly.

The program simply polls what TOS is reading from the drive, thats all.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

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Re: Choosing between three Sony MPF-920 drives

Post by Pacman » Mon Oct 23, 2017 11:51 pm

The preliminary conclusion is then perhaps that with a Mega STe at least I will still need to have CTIN shorted on a Sony MPF-920 drive while with a normal ST (such as my STe) and the version 6 Exxos HD module board I might not (as the HD module takes care of everything). I'm soon going to attend to the STe, so we'll see.
Mega STe | MonSTer with dual IDE-CF memory card adapter | STe | SM-144 |NEC Multisync 1990SXi | IDE doubler | ST_ESSC | RSVE | ICD Link II | Link '97 | HD floppy drive/AJAX | HD floppy module | Minolta PCMCIA card-drive | Realtime Clock module | Discovery cartridge | Unitor-2 | Export | Combiner | Steady Eye | Human Touch | Unicorn USB

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Re: Choosing between three Sony MPF-920 drives

Post by exxos » Tue Oct 24, 2017 11:36 am

Pacman wrote:
Mon Oct 23, 2017 11:51 pm
The preliminary conclusion is then perhaps that with a Mega STe at least I will still need to have CTIN shorted on a Sony MPF-920 drive while with a normal ST (such as my STe) and the version 6 Exxos HD module board I might not (as the HD module takes care of everything). I'm soon going to attend to the STe, so we'll see.
I've got to hook up a machine later anyway, so I will try Sony drive and solder over the switch to see if it does anything. It could be the switch does the same job as the V6 module, in regards to media detect, though when I was originally designing the kit and experimenting with floppy drives, a lot of the drives did not have this switch anyway, so I never really investigated it on the drive itself.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
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Re: Choosing between three Sony MPF-920 drives

Post by exxos » Tue Oct 24, 2017 11:50 am

So with TOS 206 & TOS 104 with the floppy write protected, without any mods to the drive, initially the programme says disk has definitely not changed, the when the floppy drive motor turns off, it says disk may have changed. So would see media detect works perfectly well here.

However with the floppy write enabled, with TOS 104 & 206, it says the disc has definitely not been changed.

I soldered over the second switch on the back of the drive, and still says disk has definitely not been changed.. So soldering over the switch did not do anything.

When I eject the floppy it says the disc may have changed.. This is with the switch Soldered over.

Without the switch soldered over the message stays on disc has definitely not changed..

So it appears the switch does do something when soldered over, but only when the floppy itself is ejected. Obviously write protect also has the same effect.

In any case, it would seem beneficial to solder over the switch, then it least TOS will recognise the disc has been ejected and likely being changed, so it will reread the FAT.

On my floppy module, the media detect should say the disc has changed without ejecting the floppy... So every time the disc is accessed, changed or not, it should reread the FAT.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

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