Re: 800k floppy on a Mac Classic II to transfer files to IIgs

[dempson@actrix.gen.nz (David Empson)]

Greg Buchner <null@none.invalid> wrote:

> In article <1i5rott.1u0j73tk7d0pqN%dempson@actrix.gen.nz>,
>  dempson@actrix.gen.nz (David Empson) wrote:
> 
> > Tristan Mumford <xtristan.xmumford@xgmail.xcom> wrote:
> > 
> > > The Classic seems to do a fair job of making floppies. I can't vouch
> > > for the classic II though. As it has been said though, formatting on
> > > the IIgs first does make a difference.
> > 
> > Regarding the formatting issue: there are two potential problems.
> > 
> > If you use a Mac which is "too new" to format the disk, its drive is not
> > a real SuperDrive. Later Macs switched from the Sony mechanism used in
> > the original SuperDrive to a cheaper one (made by Mitsubishi?). The way
> > to tell them apart is whether the drive will "grab" a disk and pull it
> > in when you insert it. If you have to manually push it all the way in,
> > it is the newer/cheaper type, not a Sony SuperDrive.
> > 
> > The newer drive is not as accurate as the old one for handling the
> > variable rotation speed used on the 400K and 800K GCR formats, so if you
> > a format a 400K/800K disk in one of these drives, it may not work
> > reliably. No problem for 720K or 1440K MFM formats, which use fixed
> > rotation speed, but they need a SuperDrive and SuperDrive card on the
> > IIgs. The newer drives can read 400K/800K well enough, and seem to be OK
> > for writing as long as the disk was formatted in an older drive.
> 
> FWIW, the newer model Superdrive in my Quadra 650 writes 800K ProDOS 
> disks that the drives hooked up to my IIGS read just fine.  This has 
> been with preformatted 720K MS-DOS disks.  Same couldn't be said of the
> drive in my PowerMac 7500, which I seem to recall looks exactly the same.

Hm. Maybe there was another transition to an even cheaper drive
mechanism which is harder to spot. I don't own any Macs older than a
PowerMac 7600 (other than a no-go second hand SE/30) so can't do any
direct checks.

It could be a PowerMac vs 68K issue, but I think that is a coincidence.
The PowerMac is newer and probably has a more recent drive model.

-- 
David Empson
dempson@actrix.gen.nz