Reading DFS floppies on a modenr PC.

discuss PC<>Acorn file transfer issues & the use of FDC, XFER, Omniflop/disk etc.
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Reading DFS floppies on a modenr PC.

Post by Prime » Mon Oct 03, 2016 5:52 pm

Hi all,

I've just descovered something that might make backing up old 5.25" disks on a modern machine *MUCH* quicker.

I've been playing with archiving some old educational software that I think came from the college I used to work at, all I could work out was that it was Beeb software.

I could get the disks to read under OmniFlop on Windows, but it was taking ages to make an image and was re-calibrating the heads almost every track.
Under Linux I couldn't get the disks to read at all :( no matter how much playing about I did with setfdprm :( Oddly 3.5" where absolutely OK.

So I start googling today at work and find this : ... .html#addr The interesting bit is that with 5.25" drives, modren PCs sometimes have problems reading disks written on a WD controller, because it didn't leave enough gap after the index pulse before beggining to write the track data.

The solution, stop the index pulse from the controller whilst reading the disk, so soldering iron and a switch in line 8 later, I try it, first in Linux and bang it works first time, then switch to windows and try Omniflop, and it steps through an 80 track disk in about 15 seconds with no recalibration.

So I deffo think this mod is worth doing, though this will only work for **READING** disks, it won't work for formatting / writing as the index pulse is required to time the start of the track but certainly makes archiving much faster.



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Re: Reading DFS floppies on a modenr PC.

Post by CMcDougall » Mon Oct 03, 2016 7:20 pm

^ :shock: =D> =D> =D>
pity none of my desktop PCs can deal with FM DFS :x only crappy MFM ADFS :roll:
only my an old Toshiba Satelite Laptop deals with FM, but only has a built in 31/2" drive,
so 51/4" either get copied to 31/2" first or now just UPURSd 8)

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Re: Reading DFS floppies on a modenr PC.

Post by flaxcottage » Mon Oct 03, 2016 7:34 pm

A good dodge but my PC only has 3.5" disks so I can't use it.

Any MIA titles in the educational stuff you are archiving?
- John

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