Can't read Mac 1.44M HD floppy disks with CrossMac or A-Max 2.5

[superfrog]

I am unable to read Mac-formatted 1.44M high-density floppy images using either CrossMac or A-Max 2.5 (the earliest version of A-Max to support HD floppies.) Unlike 800k low-density floppies, which are unreadable on an Amiga without a real Mac-compatible 800k floppy drive connected through an A-Max cartridge, Mac HD floppies are written using the exact same physical encoding and geometry as MS-DOS HD floppies, and so are readable directly in high density Amiga floppy drives using CrossMac or A-Max version 2.5 or later.

However, CrossMac and A-Max both report HD disks as unreadable upon insertion. I have verified that the floppy images I'm using are valid, and I can mount and read them with CrossMac using the fmsdisk.device virtual floppy driver, so it definitely seems to be a problem with WinUAE correctly recognizing or passing the data from the disk image to the emulated Amiga OS. I can also read MS-DOS 1.44M HD floppy images using CrossDOS without any problem as well.

Has anyone else had success reading HD Mac floppies with CrossMac?

Toni, can you think of why this would not work? Does WinUAE make PC/DOS-centric assumptions about floppy images that are 1.44M in size?

[Retro1234]

Just curious can you make A-Max boot from the fmsdisk.device mounted Disk?

[Tomislav]

By default floppy drives are defined as 3.5" DD. Did you tried to change that to 3.5" HD?

[Toni Wilen]

Nothing is modified, image track simply gets converted to raw bit stream. Note that exact size of different gaps are not exactly defined so there is possibility some programs expect some narrower range.

I am not going to debug this without more information (and guarantee that problem is not caused by something else), for example which is exact floppy controller chip used in those macs?

[Misclegend]

Originally Posted by superfrog

I am unable to read Mac-formatted 1.44M high-density floppy images using either CrossMac or A-Max 2.5 (the earliest version of A-Max to support HD floppies.) Unlike 800k low-density floppies, which are unreadable on an Amiga without a real Mac-compatible 800k floppy drive connected through an A-Max cartridge, Mac HD floppies are written using the exact same physical encoding and geometry as MS-DOS HD floppies, and so are readable directly in high density Amiga floppy drives using CrossMac or A-Max version 2.5 or later.

However, CrossMac and A-Max both report HD disks as unreadable upon insertion. I have verified that the floppy images I'm using are valid, and I can mount and read them with CrossMac using the fmsdisk.device virtual floppy driver, so it definitely seems to be a problem with WinUAE correctly recognizing or passing the data from the disk image to the emulated Amiga OS. I can also read MS-DOS 1.44M HD floppy images using CrossDOS without any problem as well.

Has anyone else had success reading HD Mac floppies with CrossMac?

Toni, can you think of why this would not work? Does WinUAE make PC/DOS-centric assumptions about floppy images that are 1.44M in size?

make the Mac disks using the program winimage, the disks should be named .IMA, it should work on winuae

[superfrog]

Originally Posted by Retro1234

Just curious can you make A-Max boot from the fmsdisk.device mounted Disk?

Not directly, because A-Max only supports real floppy drives, hard drives and partitions connected to supported controllers, and its own internal RAM disk as bootable storage devices. It is also not possible to use AmigaOS-level hacks like using AssignDev to redirect calls to DFx: to another device, because the earlier (pre-4.0) A-Max versions bypass the Amiga OS entirely and talk directly to the Amiga hardware while the Mac emulation is running. A-Max IV runs in a much more system-friendly manner, and so offers a lot more options for ways to access and boot from volumes that are stored in disk files, but I haven't tested A-Max IV much at all yet.

Your question did prompt me to think about what might work though, and the closest I was able to get is to attach a small hardfile (~1.0 or ~1.5 MB) with the exact same CHS geometry as an 800k or 1440k floppy drive (80/2/10 for 800k, or 80/2/18 for 1440k) and give it the name "AMAX0" or similar, so that A-Max will recognize it as a Mac hard drive. Then mount the Mac floppy image attached to fmsdisk.device as FF0: or similar, and from the shell "DiskCopy FF0: to AMAX0:". Then set A-Max to mount and boot AMAX0, and it will boot from the volume you just copied.

I tried taking the more direct approach of just attaching the Mac floppy image to the Amiga as a hardfile and booting it from A-Max, and while it did recognize it as a bootable volume, only 2 seconds into the boot process the emulated Mac crashed and restarted. I'm not sure why attaching a floppy image as a hardfile wouldn't work, since I can attach a standard Mac hardfile that I create using Basilisk II, Mini vMac, or HFVExplorer to the emulated Amiga and use it with A-Max with no issues at all. Using said emulators, I can also attach a floppy image as a hard file and boot from it.

[superfrog]

Originally Posted by Misclegend

make the Mac disks using the program winimage, the disks should be named .IMA, it should work on winuae

Bingo!

After changing the image file extension to .ima or .img, I can now mount and use it with CrossMac and boot it in A-Max. I didn't think the extension would matter in this context, and many of the Mac System floppy images available to download from various sites have a .dsk extension.

WinImage is irrelevant here, because WinImage only works with DOS FAT filesystems; it has no support for Mac HFS.

Thanks for the idea!

[superfrog]

Originally Posted by Toni Wilen

I am not going to debug this without more information (and guarantee that problem is not caused by something else), for example which is exact floppy controller chip used in those macs?

Lucky for us, this time there is no debugging to do, as changing the image file extension to .ima or .img did the trick (see my reply to Misclegend's post.)

I do have one other related question though:

Is it possible to add support for reading/writing Mac low-density 800k images directly in WinUAE? Basically, this would be like emulating a Mac 800k floppy drive connected to an A-Max cartridge in the external floppy port, allowing direct use of 800k floppy images with CrossMac and A-Max, and would eliminate the need for various hacks and workarounds when using 800k images. Is this possible to add? I asked about it in an earlier post:

http://eab.abime.net/showthread.php?t=100127

800k Mac floppies are unusable in real Amiga floppy drives because Mac low-density drives used variable spindle speeds, but obviously this is a non-issue when using disk images. The Zorro-II card supplied with A-Max II+ and IV allowed the use of Mac 800k floppies in standard Amiga drives through some sort of clever trickery, but I don't know how it actually worked.

[Retro1234]

Thanks for your reply, thats a shame Im interested in any way of getting A-max version below IV to boot(for real hardware) as it has very limited .amhd drivers.

Edit:::

Originally Posted by superfrog

Your question did prompt me to think about what might work though, and the closest I was able to get is to attach a small hardfile (~1.0 or ~1.5 MB) with the exact same CHS geometry as an 800k or 1440k floppy drive (80/2/10 for 800k, or 80/2/18 for 1440k) and give it the name "AMAX0" or similar, so that A-Max will recognize it as a Mac hard drive. Then mount the Mac floppy image attached to fmsdisk.device as FF0: or similar, and from the shell "DiskCopy FF0: to AMAX0:". Then set A-Max to mount and boot AMAX0, and it will boot from the volume you just copied.

Was this A-max II ? what Hard Drive driver did you use?

[Toni Wilen]

Did you use different extension in different tests? Type of image will be only guessed from image size if file has known common extension, otherwise it is assumed to be (possibly truncated) adf.

[Misclegend]

Originally Posted by superfrog

Bingo!

After changing the image file extension to .ima or .img, I can now mount and use it with CrossMac and boot it in A-Max. I didn't think the extension would matter in this context, and many of the Mac System floppy images available to download from various sites have a .dsk extension.

WinImage is irrelevant here, because WinImage only works with DOS FAT filesystems; it has no support for Mac HFS.

Thanks for the idea!

also you can use extended adf images as MAC floppies, dd or hd
it works because I tested it long time ago
just create an extended ADF then you can insert the disk in fusion or shapeshifter emulators then you format the floppy there as MAC floppy then you can mount it in workbench using CrossMAC using MAC0 and MAC1 dosdrivers

[superfrog]

Originally Posted by Retro1234

Was this A-max II ? what Hard Drive driver did you use?

I used A-Max 2.5 for this test, with scsi.amhd, the driver for A590/A2091 and A3000 motherboard SCSI.

[Retro1234]

Originally Posted by superfrog

I used A-Max 2.5 for this test, with scsi.amhd, the driver for A590/A2091 and A3000 motherboard SCSI.

Ok thanks Im wondering You set up a HDF and Selected A590 under Winuae?

im just wonder if this could be used on a real Hardware thats not A590.

Thanks.

[superfrog]

Originally Posted by Toni Wilen

Did you use different extension in different tests? Type of image will be only guessed from image size if file has known common extension, otherwise it is assumed to be (possibly truncated) adf.

I used .adf for the Amiga 1.76M floppy test and .img for the MS-DOS 1.44M floppy test, and they both worked as expected. I was using .dsk for the Mac HFS 1.44M floppy tests, because that was the extension the disk images already had when I downloaded and unpacked them. Those images now have .img extension and work perfectly.

[AMIGASYSTEM]

So if i understand correctly the 800k image floppies "can't" fit on AmigaOs (CrossMACFileSystem) right?

I tested some 800k floppies downloaded from HERE (MacOS_6.0.zip), the extension is .image

[superfrog]

Originally Posted by Retro1234

Ok thanks Im wondering You set up a HDF and Selected A590 under Winuae?

im just wonder if this could be used on a real Hardware thats not A590.

Thanks.

I used A3000 configuration, with A3000 motherboard SCSI.

I would think that any storage device that has an .amhd driver written for it could work with this method. While I used a hardfile attached via WinUAE for the pseudo-floppy AMAXx: volume, using real hardware one could try to create a very small partition on a hard drive connected to an .amhd supported controller, name it AMAXx, and mount/boot it from A-Max 2.0+.

The tricky bit here would be getting the device geometry to match that of a real floppy drive. Perhaps if you could suppress auto-mounting of the partition, and mount it manually with a custom MountList entry specifying the correct device name and geometry (and being extra careful that the custom geometry specifies a total block count that does not cross the boundary of a neighboring partition) it maybe could work...

Perhaps I will have a try at this when I have some time.

[Retro1234]

Ok Ok thanks again for your replys, Im looking for ways for Amigas that dont have .Amhd like A600.

[Toni Wilen]

Was there any Amiga floppy port to variable speed mac drive hardware interfaces or was A-Max hardware the only one that accepted mac drives?

[mark_k]

AMIA, and I think CrossMac might have come with (optional?) hardware.

I have an AMIA cartridge, could maybe be prodded into looking at e.g. the Emplant ConverterII program code at some point...

[mark_k]

Originally Posted by AMIGASYSTEM

So if i understand correctly the 800k image floppies "can't" fit on AmigaOs (CrossMACFileSystem) right?

I tested some 800k floppies downloaded from HERE (MacOS_6.0.zip), the extension is .image

WinUAE doesn't natively support the Emplant/A-Max 800KB disk format, but you can use extended ADFs. The Emplant ConverterII program can write Apple Disk Copy 4.2 images to A-Max (or Emplant) format disks.