Floppy Disk Compatibility Matrix

[Mac128]

Working on a guide to help us all. This is what I've got so far. Anybody with additional information to help clarify or correct this will be greatly appreciated. In particular, I'm a bit foggy as to what happens with early OS X systems. Also, this is in context of OEM Apple drives and Superdrives, not third party drives.

 

[Charlieman]

As mentioned in an earlier thread, my old notes suggest that PC Exchange and disk imaging utilities play their part in how a particular version of the operating system handles floppy disks.

System 7.1 with no PC Exchange

A floppy disk can be formatted as 400KB MFS. Disk imaging tools work fine.

System 7.1 with PC Exchange 2.0.5 from System 7.5.3

A floppy disk can only be formatted as 800KB HFS. Disk imaging tools not tested.

Mac OS 8.0 with no PC Exchange

Format only as 800KB HFS

400KB MFS rejected by Finder (ie no read)

DiskCopy 4.2:

-- 400KB disk rejected when trying to create an image

DiskCopy 6.3.3:

-- 400KB disk rejected when trying to create an image

-- mount 400KB floppy image failed

-- write image to floppy worked! After writing an image, I could insert a different 400KB MFS disk and create an image. Mounting still failed

 

[Mac128]

DiskCopy 4.2:

-- 400KB disk rejected when trying to create an image

DiskCopy 6.3.3:

-- 400KB disk rejected when trying to create an image

-- mount 400KB floppy image failed

-- write image to floppy worked! After writing an image, I could insert a different 400KB MFS disk and create an image. Mounting still failed

So Disk Copy cannot be used to create an image, only to make one? Fascinating. I thought 4.2 could do it.

You did not elaborate, but will 4.2 also create a disk from an image? I did not realize 6.3.3 would would make a 400K disk. Surprising. Not surprised the disks won't mount. I've read it was a bad idea to mount a 400K or 800K disk under System 7.6.1 or later, especially if it was a boot disk. I believe the mere act of trying to mount the disk will corrupt it.

How odd that Disk Copy must first write an image to disk before it will make an image from a disk. Surely that must be a bug?

Definitely worth investigating this PC Exchange problem, especially whether Disk Copy will work. As I recall, PC Exchange was an extension that could be disabled? Lot of trouble if you want to make disk copies.