//e 5.25 Floppy Media

[dfwJim]

I had an Apple ][+ then Apple //e from 1979 through the mid-90's, and now I have recently got my hands on an Apple //e with a 5.25" Unidisk and managed to audio bootstrap it with ADTPro.

I managed to find a single 5.25" diskette after rummaging through my house twice, and I was able to transfer a couple of images to it. (Hole-punched it to write to side B.)

I went to a local store with vintage stuff to obtain some more floppies, and I bypassed the apparently-new 10-packs of trustworthy brands and "cleverly" bought the cheap bulk floppies figuring I could stand a few bad ones. Bad move. Some won't format. Others fail when receiving the disk image. None of them have booted so far except my original disk found at home which works splendidly.

Since the store closed before I could return and get the diskettes i should have bought in the first place and is closed tomorrow, I've been Googling for info and trying out different disk diagnostics. XPS //e Diagnostics shows the disk RPMs at about 298 RPM, a little shy of 300, but I don't know how critical that is. When I verify media, some of the disks are just horrid all over with bad sectors, but many only fail a bunch of sectors in tracks 0 and 1 but pass the rest of the tracks fine. If I recall, tracks 0 and 1 are on the outer edge, yes? I'm wondering if the outer tracks are more sensitive to speed.

Then I read somewhere that Apple 5.25" drives don't do well with the high-density floppy media because they don't have a reinforced hub, and sure enough my lone reliable diskette has a reinforcing ring around the center hole, and my "bargain" floppies don't. Do the reinforced hub rings make a difference?

 

[david__schmidt]

Then I read somewhere that Apple 5.25" drives don't do well with the high-density floppy media because they don't have a reinforced hub, and sure enough my lone reliable diskette has a reinforcing ring around the center hole, and my "bargain" floppies don't. Do the reinforced hub rings make a difference?

Apple 5.25" drives don't do well with HD media, period. It just so happens that HD media almost always is hub ring-less, so it's a really good indicator if they're otherwise unlabeled. (I have seen hub ring-less DD media, but very rarely; I've never seen HD media with a hub ring.) The disk surface is usually really shiny and very black, generally more than DD media. But yeah, if you have HD media, throw them away. Go back and get DD disks.

 

[SomeGuy]

It sounds like your drive is fine, you just grabbed some high density disks when you need "double density" instead. Generally, HD disks won't successfully format low (single/double) density regardless of the system. Something to do with the strength of the magnetic signal. The disks are probably good, but you won't be able to use them unless you have a high density/1.2mb drive.

So when you look for disks, just look for "Double Density". That what the Apple II 5.25" drives need.

What kind of physical store even sells stuff like that?

 

[vwestlife]

High-density 5.25" disks require twice the magnetic field strength (coercivity) to format as double-density disks, so a single- or double-density drive attempting to format an HD disk will either report lots of bad sectors or just give up entirely.

Coercivity of various floppy disk media:

8" all formats: 300 oersteds

5.25" double density (360K): 300 oersteds
5.25" quad density (720K): 300 oersteds
5.25" high density (1.2MB): 600 oersteds

3.5" double density (720K): 665 oersteds
3.5" high density (1.44MB): 720 oersteds
3.5" extra-high density (2.88MB): 900 oersteds

 

[dfwJim]

Thanks. My bulk disks were indeed HD. I went back and picked up some new-in-box Verbatim double density diskettes, and they are working like champs.