5.25" floppy drive alignment?

Thread Starter

spinnaker

Joined Oct 29, 2009
7,835
I am refurbishing an old computer that has a 5.25" drive. One of the things on the list is to get the drive up and running.

From my PC repair days, I seem to remember a special disk that you would need to insert to do an alignment. Anyone know if I am recalling this correctly?
 
Yes, your memory is consistent with mine. As I recall, There were three big aspects to keeping those going. Cleaning the heads (easy). Setting the speed (easy) and aligning the heads over the "ideal or factory made tracks" (maybe add fixing the zero track switch or notch as in the case of the commodore drives). The latter required a commercial disk and the need was frequently inflated. See http://www.vcfed.org/forum/showthre...-maybe-this-can-become-an-FAQ-on-this-subject and http://www.atari-forum.com/viewtopic.php?f=15&t=32354

As I recall, an out of alignment drive can format, read and write floppies without a problem. If it is really badly out of alignment, it is not going to be reading other floppies (used with correctly aligned drives) and "correct" drives may not be able to read ones made on the out of alignment drive.

I thought you were going to use an SD card?
 

SamR

Joined Mar 19, 2019
3,453
The old Seagate 10-30 meg hard drives were notorious for "head drift". I used a program called ScanDisk that copied the entire hard disk and rewrote it sector by sector so it would be aligned to where the head was now after drifting. You had to catch the drive before the head drifted too far out of alignment making the data corrupt. It was on a 5 1/4" floppy you put in the floppy drive to execute it. To do the same for the floppy drive it was just "copy a: b": if memory serves me right. Easy if you had 2 floppy drives else you had to swap the disks in and out a few times to do it. I don't know of any way to physically realign a drive.
 

ian field

Joined Oct 27, 2012
6,539
I am refurbishing an old computer that has a 5.25" drive. One of the things on the list is to get the drive up and running.

From my PC repair days, I seem to remember a special disk that you would need to insert to do an alignment. Anyone know if I am recalling this correctly?
Such a disk is probably going to be rarer than rocking horse manure nowadays.

Any random disk depends on how well the drive that wrote it was aligned - try aligning the drive with a "decent specimen" - then see if it can read any other known good disks you can throw at it.
 
The old Seagate 10-30 meg hard drives were notorious for "head drift". I used a program called ScanDisk that copied the entire hard disk and rewrote it sector by sector so it would be aligned to where the head was now after drifting. You had to catch the drive before the head drifted too far out of alignment making the data corrupt. It was on a 5 1/4" floppy you put in the floppy drive to execute it. To do the same for the floppy drive it was just "copy a: b": if memory serves me right. Easy if you had 2 floppy drives else you had to swap the disks in and out a few times to do it. I don't know of any way to physically realign a drive.
I remember ScanDisk very well. Great program for TRS80. You could do all sorts of interesting stuff like complete track reads and play with sector numbers - cool stuff. I may still have it.
 

ian field

Joined Oct 27, 2012
6,539
I remember ScanDisk very well. Great program for TRS80. You could do all sorts of interesting stuff like complete track reads and play with sector numbers - cool stuff. I may still have it.
Some of those incorporate sector recovery routines that seek both inward and outward to null out any settling error. Most re write the sectors once they think they've recovered the original data reliably.

Performing that operation would totally defeat the objective of aligning the heads to a factory formatted standard disk - and ruin the disk if you allow it to perform the write.
 
Argh, not ScanDisk (which I loved) I was thinking of SpinWrite.
I do still have a 5.25 spinwrite [PC] disk and it was a great program - saved my butt more than once with a low-level format.

But the TRS80 program I am thinking about may not have been called scandisk. I probably have the manual if it has not been destroyed in storage.
 
Some of those incorporate sector recovery routines that seek both inward and outward to null out any settling error. Most re write the sectors once they think they've recovered the original data reliably.

Performing that operation would totally defeat the objective of aligning the heads to a factory formatted standard disk - and ruin the disk if you allow it to perform the write.
I don't know what you are talking about and I never ruined a disk with that program, whatever it was called.
 

SamR

Joined Mar 19, 2019
3,453
ScanDisc was a shareware written by the guy who did the PC IT for the US Military Acadamy. It gave you a beautiful sorted tree file directory long before the commercial ones that came after it. Norton Utilities? Would show the actual machine code, link in a word processor of your choice for file editing, file and directory management, backups, lots of really neat stuff. I had it licensed for our corporate use and continued using it even after Window came out. And it was CHEAP! or free for personal use.
 

SamR

Joined Mar 19, 2019
3,453
defeat the objective of aligning the heads to a factory formatted standard disk
For a floppy drive, yes. I saved many a hard drive (and their data) w/ SpinWrite back when I was the corporate PC goto guy. The factory techs would leave drives for me to swap out quicker than the week or so it would take scheduling a factory service call. I would (out of the ~200 PCs) swap out a floppy at least every week and SpinWrite a hard drive at least once a month.
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,835
Such a disk is probably going to be rarer than rocking horse manure nowadays.

Any random disk depends on how well the drive that wrote it was aligned - try aligning the drive with a "decent specimen" - then see if it can read any other known good disks you can throw at it.

Unbelievable but they are available on a site that sells retro PC parts. What is rare is bare 5.25". I am shocked how hard it is to find new ones. One thought I had (if I could find the drive datasheet) was to build an interface card for the Atari 800. I have the complete documentation and at first blush an interface card would not be too difficult using a modern mcu. Interfacing to the acual drive is an unknown.

I could kick myself for not salvaging one or two from the old PCs I have thrown out over the years. :mad:
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,835
Yes, your memory is consistent with mine. As I recall, There were three big aspects to keeping those going. Cleaning the heads (easy). Setting the speed (easy) and aligning the heads over the "ideal or factory made tracks" (maybe add fixing the zero track switch or notch as in the case of the commodore drives). The latter required a commercial disk and the need was frequently inflated. See http://www.vcfed.org/forum/showthre...-maybe-this-can-become-an-FAQ-on-this-subject and http://www.atari-forum.com/viewtopic.php?f=15&t=32354

As I recall, an out of alignment drive can format, read and write floppies without a problem. If it is really badly out of alignment, it is not going to be reading other floppies (used with correctly aligned drives) and "correct" drives may not be able to read ones made on the out of alignment drive.

I thought you were going to use an SD card?
So was there software that came with the disk? Trying to remember.

Yes I plan to build an SD memory interface too but I still need to get to my old floppies. ;)

See other thread for an update.
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,835
I've got one in my hands now. It even has the flipdown lever to close the "door". M2551A FUJITSU LIMITED 360K. Somewhere I have a combo 1.2/1.44 drive, I am too much a hoarder...

Ya want to dump it?
I of course will cover shipping and something for your trouble. That is assuming I could find a datasheet. Or at least a general tech docs on how to control the drive. I think there might have been chips that went on the interface card. Pretty sure there was one for the Atari. I think they used a Tandon drive mechanism and Tandon controller. The controller would do all the basic control inducing format the disk. All Atari did was to provide a power supply and the serial interface between the computer and the controller chip.
 
So was there software that came with the disk? Trying to remember.

Yes I plan to build an SD memory interface too but I still need to get to my old floppies. ;)

See other thread for an update.
Yes, there were (and probably still are) alignment disks that had software on them and dedicated alignment tracks.. I remember Dysan and Acuwrite (sp) making them. But these were not trivial to use.

This page is from the RS service manual for the floppy drives circa MI days....just to give you an idea. And you needed a scope and so on - could go just far with it at the time and I have no idea if I had the alignment disk or borrowed it. One thing is for for sure, you will need a good tech manual for your drive.
IMG_8997r.jpg

Now, with the C64 drives, I bought this software, which also claimed to have alignment tracks. For the life of me, I found the box and no disk! I used to put masters in a box and work with copies and I found that box, but it wasn't in there...maybe because I couldn't copy it. It was simple to use and yes that piece of cardboard was part of the process. They even gave you quieter end stops as the 1541 would bang to track 0. Maybe something similar exists for Atari?
IMG_8996r.jpg

I hate it when you come up with these projects that drive me into rummaging around for stuff that is 30-40 years old!

The good news for me is that I found my old TRS-80 Model 1 Data Dubber. The cassette interface was so crappy, they sold signal cleaners (little more than 7414s with a few supporting parts). But get this, they required a 9-V battery and I left one in there! I was about to drop some bricks, but it was absolutely clean - not a whisper of a leak!
IMG_8993r.jpg

BTW: The program I was trying to think of was Trackcess. It let you set up tracks and sectors with whatever headers and junk you wanted. Good stuff.
 

SamR

Joined Mar 19, 2019
3,453
Sure, the only problem is my mobility is limited (don't drive anymore and "town" abt. 20 miles away). Next trip I can drop it off at the UPS store. It is in a Hewlett Packard drive box so it is a drive I took out of my original California Garage Special 8088 5MHz PC umpteen years ago and replaced with 1.2meg drives I pulled out of the HPs at work. For some reason even when they quit working in the HP they worked fine in the clone at home and other clones. Instead of throwing them out (HP didn't want them back) I put them into other folks home clones as upgrades with a new control card which was cheap. Back before Hard Disks came around it was an awesome upgrade. My email should be on my site info to PM or phone me.
 

SamR

Joined Mar 19, 2019
3,453
Kinda hard to read the chips. The lyts look good. Note the blue trim pot w/ yellow center near the bottom left of the 3rd photo. Maybe an electronic head adjust?
IMG_0416.JPG IMG_0415.JPG IMG_0409.JPG IMG_0412.JPG
I used to put masters in a box and work with copies
Boy that brings back memories. And the little patch you put over the notch to write protect the copies. God I really feel old now... I had a flip top box for about 20-30 disks that had all my "tools" in it including the boot disks and copied masters that I carried with me to troubleshoot PCs.
 

Thread Starter

spinnaker

Joined Oct 29, 2009
7,835
Sure, the only problem is my mobility is limited (don't drive anymore and "town" abt. 20 miles away). Next trip I can drop it off at the UPS store. It is in a Hewlett Packard drive box so it is a drive I took out of my original California Garage Special 8088 5MHz PC umpteen years ago and replaced with 1.2meg drives I pulled out of the HPs at work. For some reason even when they quit working in the HP they worked fine in the clone at home and other clones. Instead of throwing them out (HP didn't want them back) I put them into other folks home clones as upgrades with a new control card which was cheap. Back before Hard Disks came around it was an awesome upgrade. My email should be on my site info to PM or phone me.

No problem at all. This is a project I likely won't tackle for some time. Some many others on the list. ;)
 
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