Quad density 5.25 floppy drive

[Vyvyan B.]

Has anyone that is using one of the XF551 clone boards with a 3.5" tried using a Tandy quad density 5.25" floppy with theirs? Mine wouldn't recognize a 1.2mb, possibly because it's 360rpm. But the Tandy 2000 used a DD 80 track, likely 300rpm which theoretically should be the same as a 720k 3.5, yes?

Edited December 1, 2022 by Vyvyan B.

[BillC]

1 hour ago, Vyvyan B. said:

Has anyone that is using one of the XF551 clone boards with a 3.5" tried using a Tandy quad density 5.25" floppy with theirs? Mine wouldn't recognize a 1.2mb, possibly because it's 360rpm. But the Tandy 2000 used a DD 80 track, likely 300rpm which theoretically should be the same as a 720k 3.5, yes?

I believe the issue is the WD1772 FDC can't handle the bandwidth for 1.2/1.44MB at the XF551 clock speed. Even the ST drives were originally limited to 720KB, this limitation was later overcome by using hand selected/tested overclocked WD1772 FDC chips(and the AJAX FDC once the WD1772 was discontinued).

Edited December 1, 2022 by BillC

[ZuluGula]

http://atariki.krap.pl/index.php/TOMS_720

Wasn't the TOMS 720 the only quad drive for Atari 8 bit?

[Vyvyan B.]

55 minutes ago, BillC said:

I believe the issue is the WD1772 FDC can't handle the bandwidth for 1.2/1.44MB at the XF551 clock speed.

The 3.5" I am using with it is a 1.44mb with a jumper on the 720k switch. The guy I got the boards from said it was basically a 1:1 clone of the XF551, only smaller. A quad density 5.25" is just a double density drive with 80 tracks instead of 40, just like a 720k 3.5"

[BillC]

1 hour ago, Vyvyan B. said:

The 3.5" I am using with it is a 1.44mb with a jumper on the 720k switch. The guy I got the boards from said it was basically a 1:1 clone of the XF551, only smaller. A quad density 5.25" is just a double density drive with 80 tracks instead of 40, just like a 720k 3.5"

Sounds like one of Zaxon's products.

 

The CSS 3.5" XF551 upgrades can also use a 1.44MB mechanism at 720KB, but can't format/read/write at 1.44MB density. You mentioned a 1.2MB(5.25" HD) drive not being recognized which is why I brought up the FDC issue. I believe most XF551 clones use the original clock speed.

 

Pin2 of the floppy interface is DENSITY SELECT, if your drive doesn't have this jumper it should be possible to remove HD capability by manually modifying the signal on this pin.

[_The Doctor__]

head structure is different on the HD drive, and using half isn't the same as a centered single on an 80 track drive. not universally interchangeable.

so head width and gap are different. this usually means the disk from lower density drive are read by all but not the reverse as the high density drive writes a disk in low density that can't be read by most low density drive...

consider them as read compatible HD drives only.

Edited December 1, 2022 by _The Doctor__

[as...]

4 hours ago, ZuluGula said:

http://atariki.krap.pl/index.php/TOMS_720

Wasn't the TOMS 720 the only quad drive for Atari 8 bit?

Not only, please check http://atariki.krap.pl/index.php/TOMS_710 

[+Stephen]

3 hours ago, BillC said:

Sounds like one of Zaxon's products.

Wonder if he stole that design like he did the U1MB?

[Vyvyan B.]

It's not a Zaxon board, I got it from a Polish guy from Poland. 😜 I'll put up some pics tomorrow.

[+Larry]

There have been quite a few threads (and a lot of good info) on this subject here at AA.  I'll look tomorrow, since I may have some of them bookmarked.

 

Edit: Sorry, I didn't find any such threads in my bookmarks.

[Vyvyan B.]

It seems to work with everything from SS/SD 40 track 90k all the way through DS/DD 80 track 720k on the 3.5" I got it to work (sort of) with a 360k Tandon TM-100-2A, it will read and write preformatted 90k disks, but it doesn't format them. Trying to format results in a timeout. I didn't try anything beyond that with it. The Tandon doesn't work with my greaseweazle either. It's from an IBM XT, so maybe it's just too old.

 

[+kheller2]

Does the TM100 have the terminating resistor pack installed and setup for the right drive letter/motor control lines?

 

 

https://www.minuszerodegrees.net/5150_5160/tandon_tm100/tandon_tm100-2_problems.htm

 

[BillC]

3 hours ago, Vyvyan B. said:

I didn't try anything beyond that with it. The Tandon doesn't work with my greaseweazle either. It's from an IBM XT, so maybe it's just too old.

I have sucessfully dumped a floppy with a TM100-1A mechanism using my Greaseweazle F7 Lightning Plus. The mechanism is the same as the Tandon 810, with the addition of sync components and a standard floppy interface board on top of the drive mechanismm, it is from a 1983 SSSD Percom AT-88S1.

[Peri Noid]

On 12/1/2022 at 7:18 PM, Vyvyan B. said:

Has anyone that is using one of the XF551 clone boards with a 3.5" tried using a Tandy quad density 5.25" floppy with theirs? Mine wouldn't recognize a 1.2mb, possibly because it's 360rpm. But the Tandy 2000 used a DD 80 track, likely 300rpm which theoretically should be the same as a 720k 3.5, yes?

Yes, I did. And it worked (720KB per disk). I used Verbatim DS/4D disks although a good DS/DD disk often is good enough. The problem with such setup is, it's not able to read standard disks any more at all. And due to the way in which the second side is handled by XF551, such disks are not readable by any other drive (like Karin Drive ot Toms 720 - if you know what I'm talking about). 

 

If the drive is a problem, some of HD drives can be modded to rotate at 300rpm with a jumper (Mitsumi/Newtronics D509V3 for instance) or with a small jumper on board (Teac FD-55GFR). And there are 80 tracks/DD drives (like Teac FD-55F/FR).

Edited December 2, 2022 by Peri Noid

[Peri Noid]

18 hours ago, Stephen said:

Wonder if he stole that design like he did the U1MB?

It was not Zaxon who stole th U1MB design - it was someone else. And it's not an anonymous person. Don't spread the lies. The XF551 schematics is available since Atari times, anyone can design a board using the schematics.

Edited December 2, 2022 by Peri Noid

[Peri Noid]

19 hours ago, as... said:

Not only, please check http://atariki.krap.pl/index.php/TOMS_710 

Don't forget Karin (mini).

[Vyvyan B.]

I was able to make an SCP image of a 360k MS DOS 3.2 disk using the TM100, write it to a new disk and then create an IMG file from that which boots in a VM with no issues. So R&W does appear to be working. The greaseweazle (v4) does not seem to care whether or not the terminator is there or not. Same result. Just can't get it to work with Atari disks for some reason.

[BillC]

1 hour ago, Vyvyan B. said:

I was able to make an SCP image of a 360k MS DOS 3.2 disk using the TM100, write it to a new disk and then create an IMG file from that which boots in a VM with no issues. So R&W does appear to be working. The greaseweazle (v4) does not seem to care whether or not the terminator is there or not. Same result. Just can't get it to work with Atari disks for some reason.

A Greaseweazle will dump a floppy without termination, however a8rawconv.exe will be unable to decode it to ATR/ATX, but will successfully decode if the drive was terminated when dumping. It took me a while to figure this out when I started, the Kryoflux/Supercard Pro devices do not require termination.

Edited December 2, 2022 by BillC

[Vyvyan B.]

I tried it with the terminator in place and without. Same result. It's odd that the Panasonic works just fine though. What is the latest version of a8rawconv? All I can find in the official thread is in the first post and it's a really old one. Maybe that's the issue.

Edited December 2, 2022 by Vyvyan B.

[+DjayBee]

45 minutes ago, Vyvyan B. said:

What is the latest version of a8rawconv?

0.94 is the latest

 

https://forums.atariage.com/topic/231835-a8rawconv-a-new-raw-disk-conversion-utility/?do=findComment&comment=4609471

 

but 0.92 is the most used one

 

https://forums.atariage.com/topic/231835-a8rawconv-a-new-raw-disk-conversion-utility/?do=findComment&comment=3490257

 

Edited December 2, 2022 by DjayBee

[ijor]

2 hours ago, Vyvyan B. said:

I was able to make an SCP image of a 360k MS DOS 3.2 disk using the TM100, write it to a new disk and then create an IMG file from that which boots in a VM with no issues. So R&W does appear to be working. The greaseweazle (v4) does not seem to care whether or not the terminator is there or not. Same result. Just can't get it to work with Atari disks for some reason.

You said you have another drive that is working fine, correct? Make SCP images with both drives and post them here, or upload them to the cloud and post a link. Don't process the images with a8rawconv or with any anything else for that matter. Just post the raw SCP images and we'll take a look. Also post the parameters and the command line you used in both cases.

 

Regarding pull ups and termination. The GW operates in open drain mode and requires pull-up on the output signals. But some GW variants might have trouble operating very old drives that have very strong pull-ups. If your GW has buffers, it shouldn't have any problem. In such case it is recommended to use termination. If you have a GW variant without buffered outputs, then it might be better to remove the termination and use a second drive on the chain to provide the pull-ups. The second drive can even be a 3.5 drive, but it must be turned on for the pull-ups to be active.

[Vyvyan B.]

12 hours ago, DjayBee said:

0.94 is the latest

 

but 0.92 is the most used one

This is what it was. The old version of a8rawconv I was using doesn't seem to recognize SCPs created with a 40 track drive. Putting the Panasonic into 40 track mode and double stepping it produced the same issue. Termination doesn't seem to make one bit of difference, at least with the v4 Greaseweazle.

[_The Doctor__]

making flux dumps of the same disk in different drives with different software, putting them up for comparison would still shed some light on difficulties and help others to overcome issues as well as possibly help development hardware and software.

[Vyvyan B.]

39 minutes ago, _The Doctor__ said:

making flux dumps of the same disk in different drives with different software, putting them up for comparison would still shed some light on difficulties and help others to overcome issues as well as possibly help development hardware and software.

Maybe one of the mods could start a new Everything Greaseweazle and Greaseweazle related thread just for that. That way, people could put all of their Greaseweazle dumps in one place. I've been using MULE as my test subject so I have a few dumps with different setting of that. One can never have too much MULE. Also have a few dumps of racing destruction set made from an original disk.

Edited December 3, 2022 by Vyvyan B.

[Vyvyan B.]

If anyone is interested, here are the flux dumps I did on the JU-475 and TM-100 drives. Mule is not an original disk, but racing destruction set was. These all convert to ATX with a8rawconv and seem to work as expected under Altirra. I have not had any luck trying to write them back to a real disk so far with either the Panasonic or the Tandon.

 

dump.zip