7 ms·

Preserving a floppy disk with a logic analyzer and a serial cable

102 points by nynyny7 8y ago

joezydeco 8y ago
A related project that has been going through an amazing amount of progress is the Applesauce Floppy Disk Controller. HN Thread here: https://news.ycombinator.com/item?id=17256709 https://news.ycombinator.com/item?id=17256709 IMO the coolest part is the widget they wrote to visualize the raw magnetic flux on the floppy. Example image: https://twitter.com/a2_4am/status/1026110390491643904 https://twitter.com/a2_4am/status/1026110390491643904
- dzdt 8y ago
  I love seeing two dimensional images of disk data. One thing it makes clear is how far ahead today's computers are, where we can easily display at many pixels per bit an image containing all of the data of a multiple-loading LARGE program from the 1980's.
- molticrystal 8y ago
  While I am sure they released plenty of images on the project's site, as an aside if you change the end of a twitter image url to ":orig", you'll get the original unresized image. In this case: https://pbs.twimg.com/media/Dj153frUUAEWAgx.png:orig https://pbs.twimg.com/media/Dj153frUUAEWAgx.png:orig Really helps you visualize the details of the data, it is really amazing, along the lines of those who look at nand gates and similar things to read decapped roms and silicon circuits. https://i.ytimg.com/vi/RqmN7_KgbFc/maxresdefault.jpg https://i.ytimg.com/vi/RqmN7_KgbFc/maxresdefault.jpg
subfay 8y ago
while impressive, I wonder where people take the time to explore ancient tech in-depth. work, family, more work. how much time do you guys have? besides, writing a n64 emulator, yes! fixing a decades old Sun, Xerox or VT terminal, yes! emulating old 8bit cpus in JS yes! but who wants to understand/explore a floppy drive?? no offense, curious what's so interesting about floppy drives compared to typical retro tech stuff I mentioned above?
- reaperducer 8y ago
  I often wonder the same thing. Except that I'm envious of both their wealth of time, and ability; rather than dismissive of their desire to understand technology at its fundamental level.
- zafka 8y ago
  I understand your sentiment,and I doubt I could make the time to do this kind of exploration myself....but, and I don't think this is why they do it- I can imagine this skill could be quite valuable when someone had some data they absolutely have to get, and it is on an old set of floppies.
- KC8ZKF 8y ago
  It’s the data that is on them.
- EvanAnderson 8y ago
  I think it's helpful to know where our technology came from for multiple reasons. (It's also fun learning to me, too.) Knowing what came before makes us better at building new (or, even better, recognizing that we might not need to build new). Our creations would frequently benefit from application of knowledge about the analogous systems that came before. There's nothing new under the sun. There is valuable analogy hiding in so many past technologies. I want to know about trade-offs made during design, how that influenced implementation, and the lessons that were learned when the technology actually made it (or didn't make it) into use. Decisions made so many years ago shaped the technology we use today (von Neumann vs. Harvard architecture, the minutiae of compatibility in x86 and the IBM PC that dates back all the way to the early Intel 8-bit CPUs the IBM 5150, etc). I think software, hardware, and protocol "archaeology" are going to become more necessary as more of the people who implemented early systems that are still in use today die. So, besides being interesting, I think there's a marketable skill in the act of being able to build understanding of past technology.
- userbinator 8y ago
  curious what's so interesting about floppy drives compared to typical retro tech stuff I mentioned above? It's one of the most widely accessible forms of magnetic storage media that you can control at such a low level.
EvanAnderson 8y ago
I read "Notes on Floppy Disks" <https://extrapages.de/archives/20190102-Floppy-notes.html> https://extrapages.de/archives/20190102-Floppy-notes.html> last night. It, along with this, really makes the technology seem much more accessible to a non-electronics professional like me. These help make the various floppy emulator devices I've got for my retro-computing habits seem more understandable. (It also really makes me want to build some electronics skills, too!)
- blattimwind 8y ago
  Magnetic recording is kinda fascinating because it is conceptually simple but very hard to do well. Conceptually all you need for a tape machine is two small write coils (erase+write) and the bias oscillator. In practice the "small coils" are complex precision parts. The circuitry of a Nagra is fairly straightforward to replicate, but building comparable tape heads in your workshop will take years.
- deleted 8y ago
  [deleted]
userbinator 8y ago
For those interested, the actual specifications of floppy disks are freely available from the ECMA: http://www.ecma-international.org/publications/standards/Standardwithdrawn.htm http://www.ecma-international.org/publications/standards/Sta... http://www.ecma-international.org/publications/standards/Standard.htm http://www.ecma-international.org/publications/standards/Sta... The standardese term is "Flexible Disk Cartridges", and the units are in Metric, but those documents basically provide almost all the information needed to build a disk drive or interpret the data on one. The CD and DVD specs are there too.
- markdown 8y ago
  > and the units are in Metric As they should be. Why is this worth mentioning?
  - tom_ 8y ago
    Floppy disks are typically measured in inches, common sizes being 8", 5.25", 3.5" and 3". Like any distance, these may also be measured in metric units. However, for whatever reason, when it comes to disks, they pretty much never are.
    - Wowfunhappy 8y ago
      Huh, is this true even outside the US? As in, did people in the UK call them 3.5 inch floppy disks, just like us Americans?
      - RL_Quine 8y ago
        Yes. Only a few things proliferate in inches, but products that are defined in inches always do. Subway sandwiches are a mixture, in the netherlands they are 30cm (an extra 30mm), in other metric countries they remain as a footlong.
        stan_rogers 8y ago
Aardwolf 8y ago
So it seems it still needs an actual floppy drive, but controls it in a better way to read it more reliably? I wonder how hard it is to build something that reads the magnetic signal, or what's left of it, directly from the floppy platter
- simcop2387 8y ago
  Take a look at the kryoflux, https://www.kryoflux.com/ https://www.kryoflux.com/
  - 0x0 8y ago
    Doesn't Kryoflux still require an actual floppy drive to be connected? I think the parent poster was looking for a way to do this without using an actual full floppy drive
    - rasz 8y ago
      Without floppy drive you would have to build a..floppy drive, kind of redundant.
    - djmips 8y ago
      Do you really think the article is about someone connecting a logic analyzer directly to a floppy sitting on the lab bench? No, he's connecting it to a floppy drive. That's only logical and also described in the article that you didn't read. Also mentioned in the article in the first paragraph is Kyroflux... Most people only read the headline before commenting?
      - 0x0 8y ago
        Thanks, I read the article and I understand all of this. I was just explaining how a kryoflux would not be appropriate for reading a floppy drive "sitting on a lab bench", which I assume is the question that the grand-parent comment was asking. Which is not an unreasonable question to ask. People have done similar things with vinyl records - reconstructing the audio from a photograph/scan of the record with no "vinyl drive". https://mediapreservation.wordpress.com/2012/06/20/extracting-audio-from-pictures/ https://mediapreservation.wordpress.com/2012/06/20/extractin...
deleted 8y ago
[deleted]
mcbrian 8y ago
hh
jakeogh 8y ago
Anyone able to recover 8" disks?

102 points by nynyny7 8y ago

A related project that has been going through an amazing amount of progress is the Applesauce Floppy Disk Controller. HN Thread here: https://news.ycombinator.com/item?id=17256709 https://news.ycombinator.com/item?id=17256709 IMO the coolest part is the widget they wrote to visualize the raw magnetic flux on the floppy. Example image: https://twitter.com/a2_4am/status/1026110390491643904 https://twitter.com/a2_4am/status/1026110390491643904

dzdt 8y ago
I love seeing two dimensional images of disk data. One thing it makes clear is how far ahead today's computers are, where we can easily display at many pixels per bit an image containing all of the data of a multiple-loading LARGE program from the 1980's.
molticrystal 8y ago
While I am sure they released plenty of images on the project's site, as an aside if you change the end of a twitter image url to ":orig", you'll get the original unresized image. In this case: https://pbs.twimg.com/media/Dj153frUUAEWAgx.png:orig https://pbs.twimg.com/media/Dj153frUUAEWAgx.png:orig Really helps you visualize the details of the data, it is really amazing, along the lines of those who look at nand gates and similar things to read decapped roms and silicon circuits. https://i.ytimg.com/vi/RqmN7_KgbFc/maxresdefault.jpg https://i.ytimg.com/vi/RqmN7_KgbFc/maxresdefault.jpg

subfay 8y ago

while impressive, I wonder where people take the time to explore ancient tech in-depth. work, family, more work. how much time do you guys have? besides, writing a n64 emulator, yes! fixing a decades old Sun, Xerox or VT terminal, yes! emulating old 8bit cpus in JS yes! but who wants to understand/explore a floppy drive?? no offense, curious what's so interesting about floppy drives compared to typical retro tech stuff I mentioned above?

reaperducer 8y ago
I often wonder the same thing. Except that I'm envious of both their wealth of time, and ability; rather than dismissive of their desire to understand technology at its fundamental level.
zafka 8y ago
I understand your sentiment,and I doubt I could make the time to do this kind of exploration myself....but, and I don't think this is why they do it- I can imagine this skill could be quite valuable when someone had some data they absolutely have to get, and it is on an old set of floppies.
KC8ZKF 8y ago
It’s the data that is on them.
EvanAnderson 8y ago
I think it's helpful to know where our technology came from for multiple reasons. (It's also fun learning to me, too.) Knowing what came before makes us better at building new (or, even better, recognizing that we might not need to build new). Our creations would frequently benefit from application of knowledge about the analogous systems that came before. There's nothing new under the sun. There is valuable analogy hiding in so many past technologies. I want to know about trade-offs made during design, how that influenced implementation, and the lessons that were learned when the technology actually made it (or didn't make it) into use. Decisions made so many years ago shaped the technology we use today (von Neumann vs. Harvard architecture, the minutiae of compatibility in x86 and the IBM PC that dates back all the way to the early Intel 8-bit CPUs the IBM 5150, etc). I think software, hardware, and protocol "archaeology" are going to become more necessary as more of the people who implemented early systems that are still in use today die. So, besides being interesting, I think there's a marketable skill in the act of being able to build understanding of past technology.
userbinator 8y ago
curious what's so interesting about floppy drives compared to typical retro tech stuff I mentioned above? It's one of the most widely accessible forms of magnetic storage media that you can control at such a low level.

EvanAnderson 8y ago

I read "Notes on Floppy Disks" <https://extrapages.de/archives/20190102-Floppy-notes.html> https://extrapages.de/archives/20190102-Floppy-notes.html> last night. It, along with this, really makes the technology seem much more accessible to a non-electronics professional like me. These help make the various floppy emulator devices I've got for my retro-computing habits seem more understandable. (It also really makes me want to build some electronics skills, too!)

blattimwind 8y ago
Magnetic recording is kinda fascinating because it is conceptually simple but very hard to do well. Conceptually all you need for a tape machine is two small write coils (erase+write) and the bias oscillator. In practice the "small coils" are complex precision parts. The circuitry of a Nagra is fairly straightforward to replicate, but building comparable tape heads in your workshop will take years.
deleted 8y ago
[deleted]

userbinator 8y ago

For those interested, the actual specifications of floppy disks are freely available from the ECMA: http://www.ecma-international.org/publications/standards/Standardwithdrawn.htm http://www.ecma-international.org/publications/standards/Sta... http://www.ecma-international.org/publications/standards/Standard.htm http://www.ecma-international.org/publications/standards/Sta... The standardese term is "Flexible Disk Cartridges", and the units are in Metric, but those documents basically provide almost all the information needed to build a disk drive or interpret the data on one. The CD and DVD specs are there too.

markdown 8y ago
> and the units are in Metric As they should be. Why is this worth mentioning?
- tom_ 8y ago
  Floppy disks are typically measured in inches, common sizes being 8", 5.25", 3.5" and 3". Like any distance, these may also be measured in metric units. However, for whatever reason, when it comes to disks, they pretty much never are.
  - Wowfunhappy 8y ago
    Huh, is this true even outside the US? As in, did people in the UK call them 3.5 inch floppy disks, just like us Americans?
    - RL_Quine 8y ago
      Yes. Only a few things proliferate in inches, but products that are defined in inches always do. Subway sandwiches are a mixture, in the netherlands they are 30cm (an extra 30mm), in other metric countries they remain as a footlong.
      - stan_rogers 8y ago

Aardwolf 8y ago

So it seems it still needs an actual floppy drive, but controls it in a better way to read it more reliably? I wonder how hard it is to build something that reads the magnetic signal, or what's left of it, directly from the floppy platter

simcop2387 8y ago
Take a look at the kryoflux, https://www.kryoflux.com/ https://www.kryoflux.com/
- 0x0 8y ago
  Doesn't Kryoflux still require an actual floppy drive to be connected? I think the parent poster was looking for a way to do this without using an actual full floppy drive
  - rasz 8y ago
    Without floppy drive you would have to build a..floppy drive, kind of redundant.
  - djmips 8y ago
    Do you really think the article is about someone connecting a logic analyzer directly to a floppy sitting on the lab bench? No, he's connecting it to a floppy drive. That's only logical and also described in the article that you didn't read. Also mentioned in the article in the first paragraph is Kyroflux... Most people only read the headline before commenting?
    - 0x0 8y ago
      Thanks, I read the article and I understand all of this. I was just explaining how a kryoflux would not be appropriate for reading a floppy drive "sitting on a lab bench", which I assume is the question that the grand-parent comment was asking. Which is not an unreasonable question to ask. People have done similar things with vinyl records - reconstructing the audio from a photograph/scan of the record with no "vinyl drive". https://mediapreservation.wordpress.com/2012/06/20/extracting-audio-from-pictures/ https://mediapreservation.wordpress.com/2012/06/20/extractin...

deleted 8y ago

[deleted]

mcbrian 8y ago

jakeogh 8y ago

Anyone able to recover 8" disks?