Fanuc format?

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JimDrew
Posts: 30
Joined: Fri Dec 06, 2013 7:52 am

Fanuc format?

Post by JimDrew »

Hey Jeff!

Do you have any experience with the Fanuc CNC machine disks? A guy sent me a disk to try to get the files off of. The disk copies no problem (with SuperCard Pro), but they are an odd bitcell timing. They are high density 1.44MB format but instead of the bitcells with 2us/3us/4us timing they are 2.5us/3.5us/4.5us timing. So, they don't decode with the standard 1.44MB timing window. I am going to shift the window just to see if they are somehow magically MS-DOS format with the timing deliberately shifted so PC's can read/write the disks.

I can send you an .scp image if you want to have a look. I am just trying to help this guy get 2 files off of his disk! Thanks for any info you might be able to give.

Jim

Jeff
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Re: Fanuc format?

Post by Jeff »

JimDrew wrote:
Sat Jul 20, 2019 12:38 am
Hey Jeff!

Do you have any experience with the Fanuc CNC machine disks? A guy sent me a disk to try to get the files off of. The disk copies no problem (with SuperCard Pro), but they are an odd bitcell timing. They are high density 1.44MB format but instead of the bitcells with 2us/3us/4us timing they are 2.5us/3.5us/4.5us timing. So, they don't decode with the standard 1.44MB timing window. I am going to shift the window just to see if they are somehow magically MS-DOS format with the timing deliberately shifted so PC's can read/write the disks.

I can send you an .scp image if you want to have a look. I am just trying to help this guy get 2 files off of his disk! Thanks for any info you might be able to give.

Jim
This can happen when you dump a disk a 360RPM formatted disk with 300RPM drive. Or maybe that one of these drives have a rpm issue.
Anyway the software can be tweaked to "fix"/correct the stream speed/rpm, but i have to check if the scp loader have this feature.

JimDrew
Posts: 30
Joined: Fri Dec 06, 2013 7:52 am

Re: Fanuc format?

Post by JimDrew »

Yep, you're right... it seems that the Fanuc machines use a HD floppy drive that is 300 RPMs. When you read it on standard 1.44MB (360 RPM) drive it is skewed about 17% because of the different drive speed.

I can use SAM Disk to decode a .scp image file and get all of the sectors, but the disk uses some kind of strange filesystem of their own. Track 0, head 1 contains the "directory" information, which is just a list of filenames and I am guessing a link to the first track/sector. From there the files are sequential. going from sector to sector in order. There are 26 sectors, each having 256 bytes of data.

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