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Correct parameters for reading a 360K floppy in a 1.2 MB drive?

tingo

tingo

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What are the correct parameters for reading (yes, reading, no writing here) a 360K floppy in a 1.2MB drive (5.25 inch, if anyone wonders)?
I recently got a few boxes of 5.25 inch 48 tpi floppies, they are labeled "Digital", "RX31K" and "2D 48TPI". I thought it would be nice to see if I could read them, so I fired of my trusty floppy "copier" machine, it has 3.5 inch and 5.25 inch floppies and runs FreeBSD:
Code: 
tingo@kg-t2$ uname -a
FreeBSD kg-t2.kg4.no 8.2-STABLE FreeBSD 8.2-STABLE #1: Mon Sep 26 13:09:55 CEST 2011
     root@kg-t2.kg4.no:/usr/obj/usr/src/sys/GENERIC  i386
Here is how dmesg detect the floppy drives:
Code: 
tingo@kg-t2$ dmesg | grep ^fd[01]
fd0: <1440-KB 3.5" drive> on fdc0 drive 0
fd1: <1200-KB 5.25" drive> on fdc0 drive 1
I use fdcontrol(8) to set the format to 360K:
Code: 
tingo@kg-t2$ fdcontrol -f 360 /dev/fd1
tingo@kg-t2$ fdcontrol -vF /dev/fd1
/dev/fd1: 360 KB media type
    Format:        9,512,0xff,0x23,40,300,2,0x50,1,0,+mfm,+2step
    Sector size:    512
    Sectors/track:    9
    Heads/cylinder:    2
    Cylinders/disk:    40
    Transfer rate:    300 kbps
    Sector gap:    35
    Format gap:    80
    Interleave:    1
    Side offset:    0
    Flags        <MFM,2STEP>
But when I try to copy the floppies with dd(1) or run disktype on them I get errors:
Code: 
tingo@kg-t2$ dd if=/dev/fd1 of=./pcsa_01_12.image bs=1024
dd: /dev/fd1: Input/output error
15+0 records in
15+0 records out
15360 bytes transferred in 7.662616 secs (2005 bytes/sec)
tingo@kg-t2$ disktype /dev/fd1

--- /dev/fd1
Character device, size 360 KiB (368640 bytes)
disktype: Data read failed at position 364544: Input/output error
FAT12 file system (hints score 5 of 5)
  Volume size 354 KiB (362496 bytes, 354 clusters of 1 KiB)
disktype: Data read failed at position 32768: Input/output error
I can believe that a few floppies are bad, but I tried twelve. Also, I can mount the floppies and list the files on them:
Code: 
root@kg-t2# mount -t msdosfs -r /dev/fd1 /mnt
root@kg-t2# l /mnt
./   ../  std/
root@kg-t2# l /mnt/*
./            msdos.exe*    win.ini*      winoldap.grb*
../           win.com*      win200.bin*   winoldap.mod*
root@kg-t2# umount /mnt
So I suspect something is wrong the the parameters.
Any hints?
 
Keep in mind that there is a higher chance for things to be not 100% standard on low-density 5.25" disks. Non-DOS OSes tend to be very narrow minded about what is possible, and easily get confused when anything is different.

There are all kinds of things in the FAT file system that can vary (cluster size, root file entries, offset to start of FAT, etc), the disks could even be formatted with extra sectors or tracks, or they might contain copy protection.

I'd start by seeing what plain old DOS reports the disks as, perhaps scan the disks with tools like ImageDisk, AnaDisk, and/or Norton Disk Test to get an idea of the format or if the disks are good and what is on them.
 
Chuck(G) said:
If these are DOS-formatted, why not just use mtools?

Otherwise, just boot up DOS and use imageDisk...
Click to expand...

I didn't use mtools because I don't know a convenient way to make an image copy with it.
Also, I fail to see how mtools will work better when dd fails because of read errors.
ImageDisk I have never used.
 
Chuck(G) said:
For all we know, these could be Apple II DOS 3.2. No 765-based FDC is going to read them.
Click to expand...

Ah! I forgot to tell you that the floppies also are labeled by Digital. Sorry about that. According to the previous owner, these floppies have never been reused, they are originals.
The labels have text like this:
B1-KH09C-XH
PCSA PC MS-WINDOWS 2.03 1/12

B1-KH10C-XH
PCSA PC MS-WINDOWS 2.03 2/12

and so on. So I don't think they are in Apple II DOS 3.2 format.
 
Last edited:
Most likely, they're for the Rainbow and the like. Get a 1.2MB drive in a PC and DOS and then look around for a file called RAINDOS (I might dig it up if you can't find it). Rainbow disks are a bit strange--96 tpi, 512/10/1/80 format with their own boot record. 3 sector FATs, 96 entry root directory--but not high-density; normal 250Kbps data rate.
 
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