My pleasure. Be aware that not all floppy disks were written the same way. Regardless of different filesystems, there were different flux encoding schemes too.
Sent from my iPhone On Oct 9, 2024, at 15:07, Tom Stepleton <steple...@gmail.com> wrote: Thanks Wayne! It's handy to get topical advice, as interesting as musings about Gary Kildall and CP/M floppy standards may be :-) Cheers, --T On Wed, Oct 9, 2024 at 8:38 PM Wayne S <wayne.su...@hotmail.com<mailto:wayne.su...@hotmail.com>> wrote: Tom, make sure to clean the heads of the floppy drive and check the heads to see if they don’t have any sharp edges, from excessive wear, that could damage the disk. Also spin it up with a scratch disk to see if it spins okay. Check the source disk for mold and dirt and see if it spins smoothly in the jacket w/o hangup. Sent from my iPhone > On Oct 9, 2024, at 12:05, Tom Stepleton via cctalk > <cctalk@classiccmp.org<mailto:cctalk@classiccmp.org>> wrote: > > Hi folks, > > I have a floppy disk data archiving project to undertake, and although I'm > aware that this can sometimes lead to spirited discussion (and hope to > avoid that!), I'm interested in current good practices for pulling data off > of hard-to-replace disks. > > In this situation, the disks are 8" floppies likely in ordinary IBM > 26-sector, 77-track, 128-bytes/sector, double-sided FM format. I have a > flux reader and will have a pair of Shugart 851 drives for the job; these > likely haven't been used for a while, though. At this stage I'll consider > the job done if I manage to get good low-level recordings from the disks: > assuming the FM data decodes well and sector CRCs look good, further > analysis can come later. > > The main risk I'm worried about is physical damage to the media. While > reportedly the disks don't show visible defects (nb: they belong to someone > else so I can't inspect them myself right now), I'm still anxious about any > chance I might find the binder that secures the magnetic material to the > cookie degraded to the point of allowing the oxide to come free. Most other > situations I think I can deal with, but I'd like to have a more concrete > plan if I start to find oxide building up on the heads. > > I'd be interested to know what precautions people might take for common > data recovery problems. One option is cyclomethicone for cleaning and > lubrication if necessary, but other than "you could use this", I'd be > interested to know details of how people put it to use if they are worried > about media failure. Meanwhile, I'm disinclined to use isopropanol or other > more aggressive solvents given received wisdom, although I know opinions > differ here. > > The disks are boot media and other materials relating to the RSRE Flex > operating system <https://en.wikipedia.org/wiki/Flex_machine> as developed > for PERQ workstations. I'm not aware of other copies of this OS being > available, though it would relieve some of the pressure to learn that these > weren't the only ones. The disks themselves are primarily ICL-branded > although a few indicate manufacture or resale by Maxell, DEC, Inmac, among > other brands. > > Is there anything else that people would advise me to look out for? > > I did find this thread > <https://classiccmp.org/pipermail/cctalk/2018-July/040673.html>, but > practices may have advanced in the past six years. I know the whiteboard > cleaner that folks seem to have liked is difficult to find these days, > particularly here in Britain. I've also had a hard time finding Photo Flo > or similar photographic wetting agents and have used deionised water with a > drop of dish soap instead. > > Thanks for any advice, > --T
