3" Disks

[foggy]

Hi!

I have just recently picked up a TC-01 with dual 3" drives. I'm looking for the best way to get software for it. Also, plug some knowledge gaps as pertains 3" disks & drives. The drives in the Tattie appear to be SS with a 34-way edge connector & molex power.

I also have:

• 1x 3" drive from a very poorly Amstrad 8256. The connector is a 26-way IDC and 'regular' power connector as you'd see on a 3.5" drive. Has Amstrad Pt No Z70312 marked on the PCB. Nothing else obvious.

• 2x 3" drives pulled from a BBC Micro. I think these are DSDD units. Connector is a 34-way edge connector. And I have a cable that'll connect them to the BBC. The drives are Sakyo Seiki Mfg Co Ltd FDU300-DA

• Greaseweasel rig.

• A couple dozen CF2 diskettes

Seems obvious to me I should get the DSDD drives working on the GW.

Question: Will the DSDD write the 200K format? When I hook one disk up to the GW and try read the disk, the activity light come on but nothing spins. I've no idea if the drives are actually working, or that the bands are intact etc. Assuming the drives are working, should the GW work in this configuration?

Question: Can I drop in one of the DSDD units into the Tattie? Same question re: media? Can I use the CF2 media in the DSDD drive? Some of the media does say 'for single head drive' but they're flippy, so what gives?

Been a long time since I've had to deal with the 3" world, any help gratefully received?

Cheers!
e

[MikeDHalliday]

Greaseweazle. Works a treat!

[foggy]

I know it does!

But I was asking about the context below!

[MikeDHalliday]

You could try System 80 instead of xtal dos. I have used that to read 5.25" DSDD floppies on the Einstein.

It is available on my server here: https://mikesretrotech.co.uk/userfiles/ ... stem%2080/

MIght get your disks working?

[foggy]

I'm interested in the hardware aspects of my questions. Once I'm able to transfer stuff about, I'll look at System80.

[MikeDHalliday]

It is probably worth changing the drive belts if there are any. The ones I had in my Einstein appeared to be direct drive so didn't have any visible belts. Some machine oil on the spindles wouldn't go a miss either. Wd40 is a no go, don't use that.

There will be a jumper block on the drives for ds0, ds1 etc and this may have additional options like power on signal. I would search online for a schematic and make sure the jumpers are set properly.

Greaseweazle should work with any drive connected as long as the software is set. Are you using command line or one of the available Guis? I find the gui is much easier to use.

No idea on the disks being used in the drives. I would imagine you just test them once the drives are working.

Could also be the data socket or finger board needs converting? Again, a schematic would help. I know zx spectrum +3 drives work with a jumper change, as do amstrad pcw 8256 drives.

I am away at the moment so cannot easily check the documentation I have on disk drives. Won't be back until 11 Sept. Will have a look through my paperwork then, if you still need help with the drives.

[retrogamer]

Welcome to the forum!

"Question: Will the DSDD write the 200K format?"

The format is written by the DOS code in RAM in the Einstein (copied from track 0) in conjunction with the floppy disc controller. The drive itself operates with no knowledge of the format which is why it's possible to use 200k, 400k, and 800k formats with the Einstein as long as the physical hardware is compatible.

I think your question is whether you can use a double sided 80 track drive as an alternative to the standard TC01 single sided 40 track drive. While this is technically possible, this will give you some problems. I can't find details of your specific drive, but the head is usually smaller in an 80 track drive and the stepper motor causes the head to travel less distance to accommodate double the number of tracks. That's why it's not recommended for Amstrad PCW users to use a 40 track disc formatted in Drive A in the 80 track Drive B. I've read that the BBC DOS uses double stepping to get around this issue of using 40 track discs in an 80 track drive. So while the 80 track drive may work in the Einstein, it may not be compatible with the standard Einstein DOS and discs formatted on the Drive or copied with Greaseweazle may not work as expected in a standard TC01 drive.

The standard TC01 Drive has one head on one side of the disc so you have to flip it to access the other side of the disc. The standard DOS will not access the other side of the disc, although if you have compatible hardware, it is possible to access a double sided drive if the Einstein DOS is updated to a later version. I've posted elsewhere in the forum about using a Gotek to simulate a double sided drive.

Hope that throws some light on your queries and I'll do my best to answer any further questions you may have. I personally use an external Gotek with Flash Floppy for maximum flexibility and convenience.

[retrogamer]

I haven’t used Greaseweazle myself, but I see that you can invoke double stepping to read and write a 40 track disc in an 80 track drive.

Clearly you should therefore be able to use Greaseweazle to copy a 40 track DSK image to a CF2 floppy disc using your 80 track drive and the resultant disc should work with the usual Einstein DOS.

I’m not aware of double stepping being implemented in any Einstein DOS so dropping the drive into your TC01 may be problematic.

Be interesting to see how you get on with this …

[foggy]

Hi, thanks for the welcome!

Right, yes, I've made some progress. I can't find any info on the drive unit myself either.

To answer my own question:
Will the DSDD write the 200K format? - Yes, it seems so. I stuck the DSDD drive into the Tattie and it seemed to function OK as a 200K single side drive. Obviously, the disks physically stopped me from flipping them so effectively I can only use one side of the disk with that drive. Attaching the DSDD drive to the Greaseweazle it seemed to be able to read and write 200K disk images fine. I've only tried 3 images, one was Elite which chugged away for a bit but then bombed with a sector error I think it said. The other images were System80 and BBC Basic - they worked fine. It seemed the incantation to get GW working was to specify "--drive 0" instead of "--drive A". Not sure what the difference is there. Keir suggested I try it and it worked. Pretty sure that's a GW thing. Also I had to specify cyls 0-39 and head 0. Interestingly, and I haven't properly thought this out yet, but I was able to write a dsk image to head 1 and it read just fine when I flipped the disk into the Tatung. I'd imagined it to have written the image the wrong way. This was just me faffing around yesterday... I'll take a more uhhh scientific approach in due course and report back!

[retrogamer]

Great news the drives work with Greaseweazle!

I would think that you could use System80 with these drives to avail yourself of the 800k format. This format uses 80 tracks with 20 sectors per track split across the two heads. Something I’ve found disconcerting in my experiments with various disc operating systems for the Einstein is that the size of the directory reported by the system may not always agree with how the actual disc is formatted, particularly when using DSK images! I’ve used a BASIC file writing loop with incrementally generally filenames to fill DSK images to check they work correctly as I couldn’t find any Einstein tools to verify the format and integrity of discs, although I have found the MOS routines useful. Do let me know if you find any relevant software tools. I suppose it was quite helpful putting the DOS in RAM on an Einstein so expansions and developments could be implemented. This was quite different from the AMSDOS solution implemented in the CPC range.

I’m thinking of getting hold of an actual 80 track drive along with a Greaseweazle rather than simulating the drive with a Gotek.

I’m intrigued to know if the Greaseweazle generated 40 track discs work with the usual DOS in the standard drive. As I said, I’ve very little knowledge of Greaseweazle to date, so am interested to confirm that your drives are actually 80 track. Sounds like they might be 40 track as they work so well!