Are my Macs too new to make 400k floppies?

[lilmul123]

I just got a "broken" Macintosh 512k (the floppy drive just needed its lube replaced) and after buying a stack of software disks from eBay, I can confirm it works 100%. I've been trying to make my own 400k disks from online disk images, but I'm having a bit of trouble doing it. First, I have a PowerComputing clone that I used to try to make a disk. I used one of the known-working 400k disks that I got from eBay to do this. I downloaded a disk image, opened up the stock copy of Disk Copy (it was 6.3.3 I believe), and made the disk. No dice. What happens is that the Mac sounds like it's starting to boot the system with the disk, but then it gets... stuck? It will begin making a constant hum like it's reading the disk (I can make a video if it helps). It will keep doing this until I either turn the machine off, or force the disk to eject.

I did some research, and figured out (from here, no less) that the recommended version of Disk Copy is 4.2 for this purpose. Additionally, I read that this version of Disk Copy should make compatible disks no matter what Mac OS version I'm using (I'm on 9.2). Same outcome.

I then downgraded the clone to Mac OS 7.6.1 (which is the earliest version of Mac OS I could get my hands on for this computer) and tried it again. Same outcome.

I only have one other classic Mac: a Powerbook G3 Wallstreet. I didn't own the floppy drive for it, so I specifically ordered one from eBay to get this working. Tried Disk Copy... same outcome.

Some things that I noticed is that Disk Copy 4.2 states that the disks I'm insterting for copy are "not Macintosh disks" even though I know they are, and they seem to work fine on the 512k. Additionally, and this is really weird, but I made a copy of one of the system disks. I first popped in the known good disk, ejected it, inserted the copy I made, and the 512k is able to read this disk as if it was identical to the working disk. It seems like some kind of filesystem table is being corrupted or unreadable? I don't know.

Has anyone experienced anything like this before? Are my Macs just too new to write these disks?

 

[PowerPup]

According to earlymacintosh.org, Mac OS 7.6 dropped support for writing MFS format. But from what I'm reading on other guides it sounds like you should be able to make the image... Do you have any 800k disks that you could give a try? As the article states, you can copy 400k images onto 800k disks.

Ah here's something: http://68kmla.org/forums//viewtopic.php?f=7&t=18023#p169328. Perhaps the disk images you have weren't made with DiskCopy. If that's the case, it might be worth giving DiskDup+ or ShrinkWrap a try. See if you can mount the images (make sure the files are locked to preserve the images,) on the G3 clone using DiskCopy. If not, then you know the images were made with something else.

 

[Mk.558]

I have not specifically tried writing on a 400K disk with a machine that can't natively write to MFS volumes by virtue of the OS. I suppose I could try installing 8.6 on the Duo 230/100 but I only have 20MB of RAM and it is the only machine I have.

Otherwise, it sounds like you have a disk image that can't be properly read. Since you have the hardware, why not try mounting it in Mini vMac and see if it detects it (use a duplicate), if not you may have more work to do, or it is corrupted. Either way I cover quite a bit about disk images in my signature in the More Info section.

 

[lilmul123]

The thing is, I am able to (supposedly) make the images myself using disks I know that boot the Mac. It still doesn't seem to make a difference. When I mount the disk in 7.6.1, I'm able to access and read from the disk just fine (which is strange).

I have quite a few 400k/800k DD disks lying around (no disks purely marked as 400k, however), and I even tried to write to one of the disks that I knew had a working system on it, and writing to that disk gave me a nice coaster.

I'll read more about disk images, thanks. PowerPup, I will also try again with the disk images using those tools, thanks

 

[onlyonemac]

A clever trick is to check the size of the disk image (not the "size on disk"). If that number divides exactly by 1024, then your image is a raw format image and disk copy 4.2 will not work-use disk copy 6.3. Even if it doesn't divide, different software might use different formats, in which case disk copy 4.2 may still not work.

 

[lilmul123]

Awesome, I will note this when I attempt this again later today. Thanks!

 

[Charlieman]

The ability to create 400KB disks is a system software feature, of course. Apple's floppy drive always supported GCR 800KB disks so it can do 400KB disks.

If you don't have a Mac that runs System 7.5.x -- the safe max for dealing with 400KB floppies -- you can try making later system software behave like System 7.5.x. Boot to a minimum system or turn off PC Exchange and the like. When I tried it five years ago, I was able to write 400KB disk images to media (in spite of error messages) but I was unsuccessful beyond that (eg mounting disk images in the Finder).

 

[JDW]

I have an SE/30 that can boot into 6.0.8, 7.1, 7.5.5, 7.6.1 and 8.1 via System Picker (I can boot 7.6 and 8.1 because I have a IIfx ROM). I can tell you from years of hands-on experience that dealing with 400k floppies in any flavor of System 7 is problematic at best. I always boot into System 6 to get the job done. You may be able to read 400k floppies on System 7, but to make reliable 400k disks, I strongly recommend System 6.

Buy a cheap Mac Plus with a System 6 floppy on EBAY or Craig's list if you want to make a lot of 400k floppies. I'm sure you'll find a separate use for the Mac Plus as well.

But if you don't have the space (or if your wife doesn't like the idea of yet another vintage Mac around the house), you may find this thread of interest. I've never tried it myself, but it looks like a good solution for those who've tried it:

viewtopic.php?p=145926