Reading From 880K 3.5" Floppy

ghborrmann · 04-27-2006, 02:57 PM

Running Red Hat v7.3 on a Dell Dimension 4100 machine, I am attempting to read disks generated on my Amiga 3000UX. That format (80 tracks, 11x2 sectors per track) is the problem, I'm sure.

When I enter,
# dd if=/dev/fd0 of=myfile ibs=512 count=1
I get a message like "probe failed". If I try,
# dd if=/dev/fd0h880 of=myfile ibs=512 count=1
I get a different message, like "can't find sector"

Is it possible to read this format on my hardware? Is this capability in my distro, or do I need to switch to another?

DragonRider · 04-27-2006, 05:17 PM

it is possible that the problem is that your actual floppy drive is incapable of recognizing the older format floppy. this is because manufacturers "assume" that you are not using older technology anymore.

try "swapping" flopy drives between machines and see if the redhat box will read the floppy. if it does than it is your floppy drive, if it can't then it's the OS

ioerror · 04-27-2006, 05:50 PM

PC drives cannot read Amiga disks, though I believe there is/was an interface card/drive available to do that (catweasel was it? Or was that something else, can't remember now).

ghborrmann · 04-27-2006, 05:54 PM

Swapping drives is not possible - the machines are too different. What has me intrigued is that there are two formats for 1440K drives: /dev/fd0h1440 and /dev/fd0u1440, but only one for 880K: /dev/fd0h880. As I read the documentation, the "h" is supposed to designate 5.25" drives, and the "u" the 3.5" floppies, but only /dev/fd0h1440 works for my 1.4M PC-compatible disks. What I apparently need is /dev/fd0u880, but this doesn't seem to be supported by the current kernel.

rkelsen · 04-27-2006, 07:08 PM

Quote:

Originally Posted by ioerror

PC drives cannot read Amiga disks

That is the answer.

The only way to read Amiga disks is with an Amiga drive.

This page may help you:

http://www.amigaforever.com/kb/3-118.html

Ciao.

Oxagast · 04-27-2006, 07:36 PM

Why can they not read amiga disks? I thought they made 880k floppy drives back in the day. Rip one outta some old 386, that might work.

rkelsen · 04-27-2006, 07:58 PM

Quote:

Originally Posted by Oxagast

Why can they not read amiga disks?

The actual drive is very similar. Chinon used to make a floppy drive which could be used in either a PC or an Amiga, but you had to change a jumper on the back of it according to which system it was being plugged into.

According to this page on Wikipedia: http://en.wikipedia.org/wiki/Floppy_...ommodore_Amiga:

The Amiga floppy controller was much more flexible than the one on the PC: it did not impose arbitrary format restrictions, and foreign formats such as the IBM PC could also be handled (by use of CrossDos, which was included in later versions of Workbench). On the PC, however, there is no way to read an Amiga disk without special hardware or a second floppy drive, which is also a crucial reason for an emulator being technically unable to access real Amiga disks inserted in a standard PC floppy disk drive.

Quote:

Originally Posted by Oxagast

I thought they made 880k floppy drives back in the day. Rip one outta some old 386, that might work.

They did, but in PCs they could only be formatted to 720k.

Even if you have the drive, it will be incompatible with the PC floppy controller. You need an Amiga style controller card if you want to do this. Like this one:

http://www.jschoenfeld.com/products/catweasel_e.htm

Ciao,

ioerror · 04-28-2006, 04:11 AM

rkelsen: that's what I said, but your answer was much better than mine. Damn, must try harder...

ghborrmann · 04-28-2006, 11:19 PM

Thanks to all who replied. I have done some programming using the flexibility of the Amiga drives, but did not realize that PC controllers were more rigid.