I'm fiddling with my last Macintosh Plus 800k floppy from High School. It's full of bad sectors and trying to do a good dump with 10 different 3.5" drives. I managed to get a good read of most of the bad sector on a drive or another but for the remaining 8 bad sectors nothing worked. I cleaned the disk with 99% isopropyl alcohol and tried another round of dumps but again no luck.
I was wondering if someone can look at the disk (again this is an HFS format):
This is quite big (578 MB compressed) as it contains most of my attempts. Maybe someone can recover the last 8 tracks from all my dumps?
In the archive, the "000-402-Mix" folder contain a mix of the good reads from many drives while the other folders are a specific dump from a single drive. Folders ending with "L" are dumps with "Density Line Low" checked while folders ending with "H" are with "Density Line Low" not checked. The folders ending with "-final" are dumps made after cleaning the floppy.
For me this is a precious floppy as it's from high school and it's in those labs where I did those (mostly boring assignments) that I decided to become a software engineer.
Thanks for your time!
PC style floppy drives are not designed to read these, so the signal must be in good strong condition for a Kryoflux to read them.
First of all, what specific brand/models of drives did you use? I have found Teac and Toshiba brand drives are the best and most others are useless.
Also, most 3.5" drives IGNORE the density line setting and use the physical notch instead. I only know of one model from an IBM machine (I forget the exact model number off hand, but I mentioned it in a previous thread) that honers the density line. Typically, overriding density does not make things "better", but it does make things "different".
Have you been able to try it in a genuine Macintosh drive? (Most of the time, Mac drives are actually worse at reading damaged disks, but in a few cases they succeed.)
You did the right thing by saving all flux dump attempts. Different software tools may have better luck. Which software tools did you use? Just the Kryoflux software?
Also do the disks look at all physically damaged? Typically, I don't recommend alcohol. At this point, I would not recommend additional cleaning, as run through drives this many time already should have left it as "clean" as possible.
BTW: Is the floppy physically HD or DD (with or without a HD hole)? I ask this because HD floppies written with DD drives sometimes look similiar in the HxC disk analyzer...
Code: Select all
Brand Model Tracks Date Condition Alps DF354H090F 84 Feb 2005 Used NEC FD1231H 82 Oct 2005 New Panasonic JU-257A827P 84 Used Samsung SFD-321B 84 Used Sony MPF520-D 82 1996 Used <--- Sets the density based on the Density Line Low/High setting instead of the density notch on the floppy Sony MPF920 84 May 2005 New TEAC FD-235HF 82 2008 New
- Yeah you are right, overriding density did not make things better but I tried everything
- I don't have a genuine Mac that I tested the disk with.
- I just used the Kryoflux software. I didn't know that the raw files were usable with something else (I'm quite new at dumping).
- I read that 99% isopropyl alcohol was safe for disks and used it with a vinyl disc cleaning cloth (since I doubted this - that's why I did this step after doing everything else possible).
- The disk surface seems OK and was always stored in a "good" environment.
- The disk is a regular 1 hole 720KB 3.5" floppy but looking at it it's labelled "KAO MF2DD Double Sided 1 MB Capacity".
For what I see in the raw data, cleaning the disk shouldn't make much of a difference. It could be a drive alignment issue...
You could try dumping the disk using that Sony drive with the drive open, and while it's past track 47 try pushing the head assembly either towards the inner or the outer tracks with your finger (not too hard that it skips tracks and NOT by pressing on the top of the head), you can often push on the spring part at the rear of the head carriage. If that results in less errors it'd suggest that the original Macintosh drive was slightly out of alignment.
If the outcome is still the same it's possible those modern drives are pushing up the signal gain too fast as the bits at the inner tracks are much wider apart than on standard PC floppies.
Some of those tracks show quite a bit of random noise. Continue to keep as many flux dumps as you can, and keep trying different drives. These dumps looks like many of the damaged Macintosh disks I have run in to - the sectors in a track may intermittently become borderline readable, so the more dumps you have of the problem tracks, the more likely you may be able to piece a track with multiple bad sectors back together as only one sector may become readable at a time. Unfortunatly the Kryoflux, by its nature, operates on whole tracks rather than individual sectors, which makes this process a pain.