Re: corrupted floppies

[supertimer@aol.com (Supertimer)]

Dan Bethe <dtm@netcomi.com> wrote:

>Hi there.  I'm having trouble with corrupted floppies.  I have a ROM01
>//gs with 1280K RAM, a vulcan 20 meg IDE drive, an 800K apple floppy
>drive, and GS/OS 6.0.1 freshly installed.
(snip...)
>FORMATTING DISKS
>================
>* in the linux pc, i insert double-density (not modified high density)
>floppy and run 'fdformat /dev/fd0H720'.  it low level formats and
>verifies ok.
>* using ProDOS floppies initialized in //gs Finder, or with MacOS.  all
>floppies have been low-level verified 'ok' on Linux, GS/OS, and MacOS
>* I download apple // files to Linux pc.

Warning...the Apple IIGS/Macintosh 800k double density Apple 3.5
drive CAN'T read the 720k PC format.  That's your problem.  The only
Apple drive that can read this format is the SuperDrive.  If you want
to go this way, you'll need a SuperDrive for your GS (or BlueDisk or
Floptical or SuperDisk connected to TurboMicrodrive IDE Filecard).

>MOVING APPLE // FILES TO FAT FLOPPY
>===================================
>* use 'mformat' and 'mcopy' to format the floppies to 720K FAT (DOS
>formatted), and copy GS files to it

MS-DOS utilities' 720k FAT (DOS) on a standard 800k Apple 3.5 drive
is not a real PC format.  The PC format has two levels, a file system
level and an encoding level.  File system is FAT and encoding is MFM.
On the GS, file system is either Prodos, HFS, or FAT (using mformat)
but encoding is GCR if you are using the standard drive.  ONLY a
high density floppy drive, floptical, or superdisk will also give you the
necessary MFM encoding to make it a FAT disk readable on a PC.

>MOVING APPLE // FILES FROM FAT TO MAC
>=====================================
>* run across the building to the Mac, copy files to Mac hard drive

This should work if you use GS Shrinkit.

>MOVING APPLE // FILES FROM MAC TO PRODOS
>========================================
>* copy files from Mac hard drive to ProDOS 800k floppies

This will work, but it is better to use HFS 800k floppies (real ones, not
fake 800k floppies that are actually high density floppies) and read
them on the GS with System 6.0.1 and the HFS FST installed.

>* usually I can copy a few hundred K of data and it's as slow as
>Christmas.

That's what I mean...use HFS.  If you use HFS (the standard Mac
format) on 800k double density disks, the copy is as fast as your
Mac usually copies.  The GS can read these disks quite rapidly too
and much faster than PC Exchange will save on Prodos disks on
the Mac.

>PC Exchange on MacOS (the control panel that allows FAT and
>ProDOS disks) moves at about 8k every 5 seconds.

Use HFS 800k disks to store your GS files from the Mac hard drive.
Use System 6.0.1 with the HFS FST installed...the GS will be able
to read, write, and format Mac HFS 800k disks.  Much smoother.

>USING THESE FILES ON //GS
>=========================
>* take my ShrinkIt files on these ProDOS disks over to //gs

Use HFS.

(bunch of read/write errors snipped...)

Use HFS.  Most likely, the Prodos disks were corrupted by the
other computer.  The GS is much more forgiving reading HFS
than another computer is about writing Prodos.  Good luck!