High-capacity disk read errors on an AT

[djfitzgerald]

I'm trying to use my AT to work with 1.2 MB "high capacity" 5.25" inch disks. I had a stack of IBM red label disks, a couple of odds and ends, and then a shrink-wrapped pack of IBM red label disks. What surprising me is that I am finding read errors on all of my 1.2MB floppies, including the ones from the shrink-wrapped box. I'm not seeing similar problems with any of my 3M 500k floppies in the same drive.

I'm suspicious that this is happening on almost all of my 1.2MB disks. Do you think this is just bad luck, or could there be a hardware problem with my floppy drive? For the record, this is the 1.2MB "A" drive in the 5170, and Norton Utilities confirms that its supposedly a 1.2MB drive.

 

[modem7]

You are not seeing any issues at all using 360K floppies, so this does not sound like a 'dirty heads' issue.

What is the background of the subject drive?
* Was it working with 1.2MB floppies earlier, or is the drive is a recent acquisition and is being tested by you for the first time?
* Make and model?

Do you not have another 1.2MB drive that you can use to prove/disprove that the subject drive is the problem's cause?

... and Norton Utilities confirms that its supposedly a 1.2MB drive.

Norton Utilities is probably seeking the information from the BIOS, which sourced the '1.2MB' information from the floppy type set into the computer's SETUP.

 

[djfitzgerald]

You are not seeing any issues at all using 360K floppies, so this does not sound like a 'dirty heads' issue.

What is the background of the subject drive?
* Was it working with 1.2MB floppies earlier, or is the drive is a recent acquisition and is being tested by you for the first time?
* Make and model?

Do you not have another 1.2MB drive that you can use to prove/disprove that the subject drive is the problem's cause?


Norton Utilities is probably seeking the information from the BIOS, which sourced the '1.2MB' information from the floppy type set into the computer's SETUP.

Unfortunately, I do not have another 1.2MB drive. And yes, this is a recent acquisition that I'm testing out the first time. I'll see if I can grab the make and model in a little bit, I'll update the thread.

 

[Chuck(G)]

For what it's worth--and I don't know if it has any bearing on your issue--I find that NOS DSHD 5.25" floppies tend to not format up as well as DSDD ones. Could be an issue with the coating. This on several HD 5.25" drives, so it's not drive-specific.

 

[djfitzgerald]

You are not seeing any issues at all using 360K floppies, so this does not sound like a 'dirty heads' issue.

What is the background of the subject drive?
* Was it working with 1.2MB floppies earlier, or is the drive is a recent acquisition and is being tested by you for the first time?
* Make and model?

Do you not have another 1.2MB drive that you can use to prove/disprove that the subject drive is the problem's cause?


Norton Utilities is probably seeking the information from the BIOS, which sourced the '1.2MB' information from the floppy type set into the computer's SETUP.

Okay, I've got some additional information now.

My 5170 is a Model 99, and the A drive is a YD-380 Type 1711, marked 1.2MB.

 

[djfitzgerald]

For what it's worth--and I don't know if it has any bearing on your issue--I find that NOS DSHD 5.25" floppies tend to not format up as well as DSDD ones. Could be an issue with the coating. This on several HD 5.25" drives, so it's not drive-specific.

Thanks, Chuck. I have to wonder if thats part of the problem here.

 

[Chuck(G)]

I think so--if you're not certain, you could try swapping the drive. A thought has occurred to me. At 1.2MB, you're running the drive at 96 tpi, so alignment is a bit more critical than if you're reading 360K floppies. Can you format a 1.2MB disk perfectly?