Re: DSDD vs DSHD disks (how to tell the difference)

[rtdos@rocketmail.com (mad ATARI user alternate)]

One way is that most later 360K disks had ring hubs while the 1.2M
disks did not (Peter Norton of Symantec & Norton Utilities fame
pointed this out in one of his books).  of course if your disks are
much older, it'd be much harder to tell the difference.  If it doesn't
say on the lable, try formatting one in high density.  The most you'll
lose if it doesn't work is one disk (some low dens drives don't like a
disk if it has been attempted to be formatted in high dens).



"Joel" <joelbuckley54.nospam.@hotmail.com> wrote in message news:<IG-dnc1r2vLTwSCgXTWcqg@comcast.com>...
> "Quadrajet1" <quadrajet1@aol.com> wrote in message
> 20021028070606.24168.00001132@mb-md.aol.com">news:20021028070606.24168.00001132@mb-md.aol.com...
> > << "Adam Barr" <omashiroi@yahoo.com> wrote in message
> > 4b54956e.0210272035.1d0531e2@posting.google.com">news:4b54956e.0210272035.1d0531e2@posting.google.com...
> > > Does any one know a place that still sells new 5.25" disks? Thanks!
> > > -Adam
> >
> >    I have a bunch of blank 5.25 disks without jackets. They are white in
>  color
> > too. Problem is, how do I tell the difference between DS/DD and DS/HD?
>  There
> > are no extra notches or markings that I am aware of, like in 3.5 disks.
> >
> >   I do run across 5.25 DS/DD disks all the time brand new in the thrift
>  stores,
> > etc all the time however.
> >
> > Raymond
> 
> I don't believe there are obvious ways to tell 360 vs 1.2M 5.25 disks.
> I don't know if this is standard or coincidence, but in looking at some of
> mine,
> the HD disk recording surface is much darker in color, blackish gray, shiny,
> while the DD is lighter, sort of brownish gray and flatter, not so shiny.
> This seems to hold up with several different brands.
> By memory, a DD disk will seldom format at HD.
> And while a HD disk will format at DD in an IBM computer, these disks can't
> be reliably read on a DD drive.
> It's not just a function of the head size and track width being smaller.
> The magnetic characteristics of the media are different.
> My memory is that HD disks did not work reliably in an Apple II.
> 
> Of course, the real spec for an Apple II disk is SSSD.
> How do you tell them apart from DSDD?
> And it was common practice to flip the disks over and use both sides even
> though DS spec doesn't really call for the disks to be rotating the opposite
> direction.