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Formatting non-RX50 diskettes in an RX50 drive

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rjarratt

Experienced Member
Joined
Mar 30, 2008
Messages
125
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I have been asked to format some floppies on my Rainbow for use in a DECmate II. I have been sent some Verbatim Single-Sided/Quad Density floppies. When I try to format them in MS-DOS 2.11 with

format a:/i
Click to expand...

I get "Format failure". Not being sure which way to orient the floppy in the drive I have tried it both ways up, with the same result. I have tried using a second RX50 drive with the same result. The drive is working because I tested it successfully formatting a real RX50 floppy.

Not really sure the Verbatim floppies are compatible with the RX50, but would welcome any suggestions.

Thanks

Rob
 
In case this helps, I can say that I used to work somewhere where they used Decmates in the typing pool.

They had disks problems from time to time, and I used to 'rescue' their problem disks. They formatted fine for me. I'm still using some of them now. Complete with the little labels with the arrow on, as they were inserted a funny way round.

I was formatting them for use on 5.25 DS 360k drive, and I was using a CP/M format VERY similar to 360k PC format. Disks seemed normal, not sure what difference QD would make, but certainly NOT HD at that time. I do believe that the disks needed to be a slightly higher spec than normal, but still normal disks.

Geoff
 
Are the disks you're trying to format new? If not, maybe someone tried to format them HD at some point, and the DEC drive is having troubles over-writing them. If so, you might need to wipe them first with something like a bulk tape eraser.

Another thing that might be worth trying might be writing to the new disks in a PC using IMD and seeing if the DEC can read them. I think I recall when the rainbow first came out you couldn't format a new disk on in, you had to buy disks from DEC, but later people wrote tools to do it. Not sure if any of that applied to DECmate.

Also are the floppies the hard sectored or soft sectored?
 
My thought to is they may already be formatted but not something the Rainbow can overwrite.
 
I was formatting them for use on 5.25 DS 360k drive, and I was using a CP/M format VERY similar to 360k PC format. Disks seemed normal, not sure what difference QD
would make, but certainly NOT HD at that time. I do believe that the disks needed to be a slightly higher spec than normal, but still normal disks.
Click to expand...
You might compare the disks to an working disk and make sure the holes (write protect, index) and it has the same number of sector holes. I don't remember if the 5.25" media ever was hard sectored or not.

Quad density disks do have a different TPI which might cause issues due to noise from adjacent tracks if the stepper mechanics are a bit wobbly. You could try bulk erasing a disk first and re-formatting it. High-Density media requires more write current, so will be unreliable in any event.

CW
 
Conventional PC high-density disks won't work in an RX50 drive in a Rainbow, BTW, if that's what you were trying. They will fail initializing.
 
Yes, HD disks shouldn't be used (the magnetic material is different) but Quad Density disks should be OK.

The 96/100 TPI is only applicable if you have the correct drive for it. It should be fine on the RX50 drive itself.

It might be just worth double checking that they are soft sectored floppies as opposed to hard sectored ones...

Yes, I can never remember which way each disk goes up (or is that down)! I had to stick arrows on the drive...

Dave
 
I just checked and the disks I have been given are hard-sectored. So I guess the RX50 can't deal with that. The disks are brand new, the box was still sealed.
 
Quad density floppys should work, but you may need to bulk erase / run around them with a strong magnet. Top floppy drive is right side up, bottom is upside down, if I remember correctly from my Rainbow...
 
rjarratt said:
I just checked and the disks I have been given are hard-sectored. So I guess the RX50 can't deal with that. The disks are brand new, the box was still sealed.
Click to expand...
Oh, yeah hard sectored disks won't work. You could try formatting some double density disks, they worked fine on my Rainbow.
 
Yep, that's a bummer...

However, someone with a North Star Horizon (or similar) might buy them off you or do swapsies...

Dave
 
You can format the DS/DD Floppy's on a96 TPI Floppy Drive with 22DISK using
the DEC1 DEC DECMate II - SSDD 96 tpi 5.25" - 512 x 10 Definition, or with
Debian Linux with a 96TPI 5.25" Floppy Drive. Debian has the following Definition
for the DEC Mate II

Code: 
# DEC DECMate II - SSDD 96 tpi 5.25"

"DEC400":
 SS QD sect=10

A standard DS/DD Floppy formatted on a 96 TPI Drive then becomes a DS/QD Image.

Larry
 
I have some DS/DD floppies, but I wanted to check them for any important contents before trying them on the Rainbow. However, both my "regular" 5.25" PC floppy disk drives are not working and I don't think I have any others, so I may have to try to fix one of these drives first before I will use one of the DS/DD floppies.
 
rjarratt said:
I have been asked to format some floppies on my Rainbow for use in a DECmate II. I have been sent some Verbatim Single-Sided/Quad Density floppies. When I try to format them in MS-DOS 2.11 with



I get "Format failure". Not being sure which way to orient the floppy in the drive I have tried it both ways up, with the same result. I have tried using a second RX50 drive with the same result. The drive is working because I tested it successfully formatting a real RX50 floppy.

Not really sure the Verbatim floppies are compatible with the RX50, but would welcome any suggestions.

Thanks

Rob
Click to expand...
Replying to an old thread, but I had this same issue and was able to solve it.

"Format failure" maybe be because the motor speed is slightly out of spec. If you run the CP/M version of FORMAT, you may actually get an error message about motor speed.

The RX50 has an adjustment pot for the motor speed, the grey long potentiometer located to the right on this picture.

RX50_5.25_inch_diskette_drive_-_spindle_motor_speed_control_PCB.jpg


There is a small Z80 program called "RFMAT" (website doesn't work for everyone) to help with adjusting the motor speed. Very small adjustment need to be made, mine was maybe 5-10 degrees off. An oscilloscope could be used as well, but not sure at which point to measure.

1689053855473.png

There is also an informative post on usenet by Roger Ivie:
The speed tolerance for the drive is not tight enough to allow the drive
to format diskettes. If I recall correctly, you need to have a drive
within 1% of 300 RPM to format the drive, but the RX50 is specced at
1.5% speed tolerance. That's not a problem reading or writing diskettes
normally as the data separator will track the drive's speed variations,
but that doesn't work for formatting; since you're not reading data off
the drive while formatting, there's no way for the data seperator to lock
to the speed of the drive.

When Digital finally released formatting softwre for the Rainbow, they
would replace the drives of people that complained they could not format
diskettes. There is a pot on the side of the drive that controls the speed
and there used to be software that would display the speed of the drive so
you could tweak it in. Those of us with DECmates and Pros were still out of
luck, though, as there is a microcontroller sitting between the processor
and the diskette controller that does not include formatting firmware.
Click to expand...
 
Hi,
Thanks desaster for the info. He is probably too modest to mention it, but he has made a couple of very useful Youtube videos on bringing up his Rainbow 100A:


Unfortunately the http://www.softsector.aplaholm.se/computers/ is down (for me?), so has anyone else got a copy of RFMAT.ZIP, I can host it if needed
Regards,
John
 
Here is the RFMAT utility, downloaded from from http://www.softsector.aplaholm.se/computers/

Tools for DEC Rainbow 100 computer:

RFMAT is a tool to adjust the speed of the floppy-drive in Your DEC Rainbow 100 computer,... If not before then after You get the:
"DRIVE SPEED OUT OF RANGE - DRIVE CANNOT BE USED FOR FORMATTING"

"Please visit Your local DEC service center" messages from FORMAT,...

RFMAT.zip version 0.03 - 6,7 KB (6 844 byte), (CP/M-80/86)
Click to expand...
 

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