[vcf-midatlantic] Bad disks

[Tony Bogan]

> On Apr 19, 2017, at 12:27 AM, Evan Koblentz via vcf-midatlantic <vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> 
> I went to format 5.25 disks from a NOS box still in shrink wrap. There were 11 disks in the box ("pay for 10, get one free"). Every disk resulted in a track error at a different track.
> 
> If you can't trust never-opened disks to be good, then how do you acquire disks?
> 
> Is there any good software to repair the errors?
> 
> ________________________________
> Evan Koblentz, director
> Vintage Computer Federation
> a 501(c)(3) educational non-profit
> 
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Evan, are you using them on the laser or your platinum IIe? If the IIe is it a disk ][ drive or the 5.25" unidisk?

Also what brand are the disks and lastly (been asked already) have you tried to do other disks since this failed batch?

The fact that you successfully formatted recently doesn't eliminate the possibility of the head now being dirty enough that it fails more than it works. As Adam mentioned I too have (actually several thousand) NOS Athana disks and have averaged only 1 or 2% failure rate at the most. Rare more than 1 or 2 out of 100 fail to format. I also have a significant number of 3m disks still sealed in packs of 10 and they rarely if ever give errors. Bonus, ultra magnetics, Kodak and a few other brands are notoriously bad even if still shrink wrapped. Maxell I've had better luck with but not as good as 3m/Athana. Verbatim? Like gold if you can find them!
Opus are fair to good, this all based in today's world of old floppies in my experience.
Regardless, first thing is clean the head, second is try floppies not from that batch. If you're still having issues with any floppies next is check the disk speed. Disk ][s will fall off in speed far more often than 5.25 unidisks in my experience. Out of alignment happens infrequently but it does happen.

I've run into and entire box of "new" bad disks but it's rare. To get zero successful formats out of 11 new disks usually means a dirty head/drive issue.
Tony