3B1 (AT&T UNIX PC) formatting a MiniScribe 3438 Hard Drive

[firebirdta84]

Or, I could name this post "Understanding the strange 'Give # Tracks per Cylinder' question"

So, trying to format a MiniScribe Model 3438 for use on my AT&T UNIX PC.

The menu offers standard options for a MiniScribe 10, 20, 40, or 64 megabyte drive, but the 3438 is a 32 megabyte drive, so I chose "11 - Others"

At which time I am asked for # of Cylinders, # of Tracks per Cylinder, and # of Sectors per track.

So, I consult the oracle of Google on this drive, and come up with this doc:

http://www.alyon.org/InfosTechniques/informatique/drives/miniscribe/rll/3438.txt

I answered:
# of Cylinders: 615
# of Tracks per Cylinder: 4
# of Sectors per track: 26



Now, I've noticed that only the Unix PC / 3B1 and the MiniFrame are known to ask the strange question "# of Tracks per Cylinder". No documentation ever gives this parameter...like ever, on any MFM hard drive.

So, I decided to think about it, logically. A cylinder is defined as all of the tracks in that position on all platters, top and bottom. And, each platter surface usually has a head, but not always...but most documentation says how many heads a drive has. So, the # of Tracks per Cylinder always has to equal the # of Heads, right? That's what I think...but I am asking the experts here. I am still new to this vintage MFM and older drive thinking. what is the right answer?

I used this logic, and the UNIX PC didn't like it.

However, I'm not sure that the tracks per cylinder is the mistake that I made, maybe it was another parameter I got wrong, or multiple? Or Maybe the UNIX PC doesn't like the MiniScribe 3438 32Mb hard drive?


Anyway, it errored:

Must be a track multiple. 39 is assumed.
Must be a track multiple. 3835 is assumed.

** ERROR **
Test : Hard disk test( Drive 0 )
Subtest: Format.
Error : WINCHESTER:Can't Write the the new VHB:Response = 10
Enter y [Y] to Abort, Return to continue:



Does anyone have any thoughts on how to enter these parameters correctly for the UNIX PC?

Thanks always,
-AJ

 

[Stone]

Are you using an RLL controller? If not, you're not going to get 26 sectors per track. An MFM controller will only format 17 sectors per track.

 

[Al Kossow]

Or, I could name this post "Understanding the strange 'Give # Tracks per Cylinder' question"

So, trying to format a MiniScribe Model 3438 for use on my AT&T UNIX PC.


Does anyone have any thoughts on how to enter these parameters correctly for the UNIX PC?

Thanks always,
-AJ

use

http://www.alyon.org/InfosTechniques/informatique/drives/miniscribe/mfm/3425.txt

as someone else said, the 3438 is rated as an RLL drive, but you have an MFM controller so everything else is the same except the sector count

 

[SomeGuy]

"Tracks per Cylinder" is just an odd way to ask for number of heads.

Unless I'm mistaken, those machines use an MFM controller, not RLL. You can still use that RLL hard drive, but you will only get 21mb of capacity instead of 32mb.

For a standard 3600rpm drive, an MFM controller can only fit 17 sectors per track - hence the default of 17. However if you were using a 3000rpm MFM drive, you would enter 21 sectors per track - hence why it asks you at all.

If you enter more sectors than what the drive/controller can handle, the end of the track will overwrite the beginning and the format will fail.

 

[firebirdta84]

Thank you all...this is exactly the knowledge that I needed!

I just tried these new parameters, and they work perfectly.

Success!

Always appreciative,
-AJ