(The Apple SuperDrive is a disk drive that can read and write in the standard
Macintosh 400K and 800K formats, as well as the newer 1.4MB format. It also
allows reading and writing 800K Apple II ProDOS, 720K MS-DOS, and 1.44MB MS-
DOS formats.)
The "Fix"
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If you put the original high-density disk back into the Macintosh Plus and
copy the 800K data from the high-density disk onto an 800K- formatted double-
sided disk, you can then put the double-sided disk into the SuperDrive, and
the Macintosh with the SuperDrive will read the data properly.
The SuperDrive also has the ability to exchange data on disks between
Macintoshes and 3.5-inch drive-equipped MS-DOS or OS/2 computers.
Here are some scenarios to help you understand the combinations of disk types,
drive use, and supported (and unsupported) combinations between the two:
- A user on an MS-DOS machine that uses 3.5-inch disks takes a brand new
double-sided disk and formats it to 720K. The user can copy his Lotus
1-2-3 spreadsheets from his hard disk to the newly formatted disk and
remove the disk from the MS-DOS machine. The user can go to the
Macintosh, launch Apple File Exchange (AFE), and insert the MS-DOS disk
into the FDHD. A listing of the contents of the disk, including the
spreadsheet that the user wants to transfer to the Macintosh, appears in
the AFE window. All behaves just as expected (well, at least, like the
manual says it will).
- A user on an MS-DOS machine who uses 3.5-inch disks takes a brand new
high-density disk and formats it to 1.44MB. The user can copy his Lotus
1-2-3 spreadsheets from his hard disk to the newly formatted disk and
remove the disk from the MS-DOS machine. The user can go to the
Macintosh, launch Apple File Exchange (AFE), and insert the MS-DOS disk
into the SuperDrive. A listing of the contents of the disk, including the
spreadsheet that the user wants to transfer to the Macintosh, appears in
the AFE window. Everything behaves as expected.
- A user on an MS-DOS machine who uses 3.5-inch disks takes a brand new
high-density disk and formats it to 720K. The user can copy his Lotus
1-2-3 spreadsheets from his hard disk to the newly formatted disk and
remove the disk from the MS-DOS machine. (In this instance, the MS-DOS
machine does not care whether the disk is high-density or not. It only
"cares" that it moved the data successfully to the target disk.) The
user can go to the Macintosh, launch Apple File Exchange (AFE), and
insert the high-density 720K-formatted MS-DOS disk into the SuperDrive.
The SuperDrive cannot read the 720K-formatted MS-DOS disk in the 1.4MB
mode, and the Macintosh gives the familiar dialog box that it is not a
readable disk, Eject or initialize".
- A user on an MS-DOS machine that uses 3.5-inch disks takes a brand new
double-density disk and formats it to 1.44MB. (Note: although this may
be possible, it is NOT a supported configuration.) The user should be
able to copy his Lotus 1-2-3 spreadsheets from his hard disk to the
newly formatted disk. The user removes the disk from the MS-DOS
machine. The user can go to the Macintosh, launch Apple File Exchange
(AFE), and insert the double-density 1.44MB-formatted MS-DOS disk into
the SuperDrive. The SuperDrive senses that the disk is not a high-density
disk (no bonus hole) and attempts to read the disk in 400K/800K mode. The
SuperDrive cannot read the 1.44MB-formatted MS-DOS disk in the 720K mode,
and the Macintosh gives the familiar dialog box that it is not a readable
disk, Eject or initialize.
(By the way, the correct MS-DOS command to format a double-density disk
to 720K in a 1.44MB disk drive is:
FORMAT A:/N:9 /T:80
This tells MS-DOS to format the disk in drive A: to 9 sectors per track
and 80 tracks, which fits the specifications of the double-density
media. If you typed only FORMAT A:, MS-DOS assumes that the disk is
high-density and tries to format it to 1.44MB. This is not a supported
configuration even though it may be physically possible.)
Summary
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When you use the SuperDrive, make sure that you are using the correct disk
for the job that you are doing. There are only two rules to remember:
1) If you are exchanging disks with older Macintoshes, Apple IIs, or 720K
formatted MS-DOS machines, use only single- or double-sided disks.
2) If you are exchanging data with SuperDrive-equipped Macintoshes or with
1.44MB-formatted MS-DOS machines (most PS/2 machines fit this
description), make sure that you are using high-density disks (the ones
with the bonus hole).