I do a lot of floppy imaging and some of my work on it has previously be discussed here[1]. I do not understand where they got the idea of "there are a number of disks that the Greaseweazle struggles to capture, namely the Apple formatted disks. If you have these disks in your collection, you may need to use an Applesauce controller."
The Applesauce is a macOS exclusive tool that has a contingent of dedicated users. While I have not imaged a wide sample set of Apple II and 800k Mac disks specifically, from my current experience the Greaseweazle is plenty capable of reading them. I would speculate the author was trying to use an included diskdef(a flux to binary decoding definition) for an incompatible disk. The Zone Bit Recording[2] Apple drives use is irrelevant when you increase the sample rate of the controller to accomplish the same thing. Similarly C64 disk drives are also ZBR but change the clock rate instead of media speed. So do not think that this means you need multiple drives and controllers when getting into floppy imaging, you can use standard PC drives with a Greaseweazle to read and write Apple II and Mac disks as well as almost anything else.
I have opened an issue on their github page for this site to seek clarification on this.
As a kid back then, floppies were expensive if you were using your pocket money or hard earned side hustle stash. Floppies were used, abused and reused until that dreadful bad sector. Even after the bad sector if you knew its location. But you knew the floppy time was up.
Kids today will newer know the feeling of unwrapping a fresh package of 10 floppies. The sound, the smell, the texture, the stickers, the formatting, the wast free space, ... as much as retail therapy is a thing, I think that was floppy therapy.
felooboolooomba
Floppy disks were ubiquitous when I was in college. When I got into Linux, I did an experiment raw writing zeros to floppies with dd to see what percentage of them had I/O errors. I tested with a stack of about 50 of them that were left in our computer lab over the years (different brands). The failure rate was staggering. Something like 30-40% of them had bad sectors. After that, I realized that I could never rely on them as a storage medium for anything important without regular backups.
tmountain
The rule for preserving floppies is to not use Windows. Windows is known for automatically writing to disks, so you're not preserving the original anymore, you're preserving the changes that Windows made to the disk.
I can't afford an the recommended Applesauce for Apple II disk preservation so I'm hoping that the Adafruit work which added Apple II drive support will work for me.
A few years back I underwent an effort to image a bunch of old 3.5” floppies I had from when I was a kid. I used KryoFlux, and had a close to 100% success rate (eventually)
Some things I learned:
1. Different drives could read different sectors. I am not exactly sure why, but some disks would show bad sectors when read from one drive, but would have a different set of bad sectors when read from a different one. I had 5-6 different drives I was using (I bought a bunch of used drives, they are pulled from old hardware and resold). I think it likely has something to do with the heads being slightly misaligned or something, so they would struggle with different sectors.
What I would do is scan a disk with one drive, and if I found any bad sectors, I would re-scan with a different drive. I would repeat this process until I had at least one good scan of each sector. I would then pull the missing sectors in one scan from a scan that succeeded on that sector, and would patch together an entire image.
2. I didn’t realize how varied the formats are for disks I had. I remember single vs double sided, but there were quite a few other variations I found in my collection.
3. If you hang out with computer nerds of a certain age, you are going to be surprised by how many of them still have a collection of old floppies that they can’t access anymore. I had so many requests to help archive many different collections!
cortesoft
It's easy to forget that preserving digital data often comes down to keeping aging physical media alive. Nice practical guide.
mune2gu-chan
If you ever want to peek at physical magnetic transitions and how that translates into bits/bytes/sectors get any Sigrok supported Logic Analyser and the FM/MFM/RLL decoder https://github.com/raszpl/sigrok-disk#screenshots
rasz
Oh memories of stacking those, and going to my friend's place to copy the latest games :)
Remember how we were drilling holes to doubled the disk's storage capacity (from 720 to 1440) https://www.vogons.org/viewtopic.php?t=47247
Before the floppy disks we were using cassettes... with our TO7 (circa 1983). It was slow by our current measure, but as kids we had time, I guess. The TO7 had even a lightpen to point at the CRC screen. https://en.wikipedia.org/wiki/Thomson_TO7
My parents attic has still some of my old floppy disks, and even maybe some cassettes.
comments (10)
The Applesauce is a macOS exclusive tool that has a contingent of dedicated users. While I have not imaged a wide sample set of Apple II and 800k Mac disks specifically, from my current experience the Greaseweazle is plenty capable of reading them. I would speculate the author was trying to use an included diskdef(a flux to binary decoding definition) for an incompatible disk. The Zone Bit Recording[2] Apple drives use is irrelevant when you increase the sample rate of the controller to accomplish the same thing. Similarly C64 disk drives are also ZBR but change the clock rate instead of media speed. So do not think that this means you need multiple drives and controllers when getting into floppy imaging, you can use standard PC drives with a Greaseweazle to read and write Apple II and Mac disks as well as almost anything else.
I have opened an issue on their github page for this site to seek clarification on this.
[1] https://news.ycombinator.com/item?id=39495973 [2] https://en.wikipedia.org/wiki/Zone_bit_recording
AkBKukU
Kids today will newer know the feeling of unwrapping a fresh package of 10 floppies. The sound, the smell, the texture, the stickers, the formatting, the wast free space, ... as much as retail therapy is a thing, I think that was floppy therapy.
felooboolooomba
tmountain
Dwedit
SilverBirch
https://github.com/adafruit/Adafruit_Floppy
djmips
Some things I learned:
1. Different drives could read different sectors. I am not exactly sure why, but some disks would show bad sectors when read from one drive, but would have a different set of bad sectors when read from a different one. I had 5-6 different drives I was using (I bought a bunch of used drives, they are pulled from old hardware and resold). I think it likely has something to do with the heads being slightly misaligned or something, so they would struggle with different sectors.
What I would do is scan a disk with one drive, and if I found any bad sectors, I would re-scan with a different drive. I would repeat this process until I had at least one good scan of each sector. I would then pull the missing sectors in one scan from a scan that succeeded on that sector, and would patch together an entire image.
2. I didn’t realize how varied the formats are for disks I had. I remember single vs double sided, but there were quite a few other variations I found in my collection.
3. If you hang out with computer nerds of a certain age, you are going to be surprised by how many of them still have a collection of old floppies that they can’t access anymore. I had so many requests to help archive many different collections!
cortesoft
mune2gu-chan
rasz
Before the floppy disks we were using cassettes... with our TO7 (circa 1983). It was slow by our current measure, but as kids we had time, I guess. The TO7 had even a lightpen to point at the CRC screen. https://en.wikipedia.org/wiki/Thomson_TO7
My parents attic has still some of my old floppy disks, and even maybe some cassettes.
llsf