VOGONS


First post, by rico001

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Greetings;
OCR floppy disk paper image
I noticed linux was dropping floppy disk support (other topic), but I had an idea.

Using spreadsheet software I was wondering if it was possible to make a colored grid that would be able to store 720kb in an image that people could scan, this way people could easily use and share floppy data.

I had begun to research the math and don't know if it was possible, I was hoping someone could quick do some math.

Here are some standards so far: 300dpi scanner, 256 color websafe,
US paper 8.5x11, Sorry not metric 🙁

possibly the format already exists? Any additional thoughts, suggestions?
Thanks for any feedback

Reply 4 of 16, by rico001

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gca wrote:

Ah ... what?

Are you thinking about something akin to a QR code or something?

Yes like that, similair to a qr code you could use a photo scanner or digital camera to scan the image that is equivilent to the data on a floppy disk. I just thought spreadsheet software such as librecalc could be used to experiment how to create the image data to be read like it was on 720 floppy disks;
Hopefully a QR Code standard wouldn't interfere with other technology? I thought this idea might work. Then you could even use scrap paper for media

Last edited by rico001 on 2019-11-13, 21:04. Edited 2 times in total.

Reply 5 of 16, by cyclone3d

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rico001 wrote:
derSammler wrote:

???

You know that you can create image files from floppy disks?

Yes... the floppy disk has to be readable though... am having troubles years later (other topic),

Scanning a floppy disk is not going to be of any help. They are magnetic media, not optical.

If you want to have something other than a real floppy drive to use floppy disk images with, you could always get a Gotek type USB floppy emulator.

If you just want the files themselves, then you can just store them on a different type of drive.

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Reply 7 of 16, by cyclone3d

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rico001 wrote:
gca wrote:

Ah ... what?

Are you thinking about something akin to a QR code or something?

Yes like that you could use a photo scanner or digital camera to scan the image that is equivilent to the data on a floppy disk.

uuuhhhh... what would be the point?

I guess you could make a program that could get the raw image from a floppy and then convert that to/from a document just filled with 1s and 0s.. but you would also have to have the date for the file names, start stop for each file, etc.

It would basically end up being an unreliable physical format of a zip file.

1. You would have to have scanners that were calibrated.
2. Whatever you use to print it with would have to print perfectly.. no lines, streaks, etc.
3. You would always have to make sure that there wasn't any dust on the scan surface.
4. What happens if your paper gets wet, torn, dirty, fades, etc.?
5. It would be even more hardware dependent than a floppy drive.
a. Calibrated scanner for each system (OS dependent)
b. Scanner software for each system (OS and scanner dependent)
c. Specific printer for making the images (OS dependent)
d. Specific paper so that the paper doesn't affect the hue of the colors.

Much easier to do just B/W... but still there are much easier ways to do transfer files such as over a network or even a null modem cable if you absolutely must.

Last edited by cyclone3d on 2019-11-13, 21:11. Edited 1 time in total.

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Reply 8 of 16, by derSammler

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rico001 wrote:

Yes... the floppy disk has to be readable though... am having troubles years later (other topic),

If you want to create a color grid from the data on the floppy, it must be readable, too.

rico001 wrote:

Yes like that you could use a photo scanner or digital camera to scan the image that is equivilent to the data on a floppy disk.

Completely senseless. You would add two or three additional steps to something you can already do by just sharing a floppy disk image.

But anyway, what you are after is called steganography.

Reply 10 of 16, by Tiido

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That's a strange thought. I'm not sure how dense the information on the paper must be to cover whole floppy worth of information, and also do so reliably. It would sort of be super QR code...
* When color is mixed in you can store multiple bits per symbol and hopefully without impacting reliability.
* Full primary colors and their combinations will let you do 3 bits / 8 states in one symbol (red, green, blue, cyan, magenta, yellow, black, white).
* One byte requires 3 symbols with the leftover 1 bit that can be used as parity to verify byte integrity.
* 720k floppy has 720000 bytes on it, so you need 2160000 symbols for all of them.
* 1748 * 1236 grid will fit all the required symbols with a handful to spare within A4 sheet (X = Y * sqrt(2))
* Each symbol needs to be about 0.17 x 0.17mm in size for the A4 sheet. This will be a very fine grid that is very sensitive to color alignment of the printer and possibly sensor alignments in the scanner itself, data recovery may not be trivial but I am no printer/scanner expert.
* At 300dpi each symbol takes 300 = 25.4mm ~ 11.81 pixel per mm ~ 2 pixels per symbol

Last edited by Tiido on 2019-11-13, 21:48. Edited 1 time in total.

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Reply 11 of 16, by BeginnerGuy

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This would be a fun little home project, however I don't know much about printers and scanners. This is stepping into an entire field and I'm assuming we have little background in compression, printing, scanning.

From a programmers perspective, one simple way to do this would be to use a palette of 255 colors + blank (to represent a 0 byte). Using this you can represent each byte using a single spec of color, rather than drawing each bit individually. With this you could read a binary file and create an image.

From paper you would scan the image into a known format (bmp?), Read the image and convert each color back to its respective binary byte.

You could go further to add a header to the data so a date, name, etc could be added and read back using the same color system.

I believe a 720k disk contains 737,280 bytes, With this system a 720k disk would require 737,280 colored markings. How small these marks can be is a future topic depending on printer and scanner ability to distinctly write and scan back 256 colors (including blank, white). I believe printers are only actually capable of printing maybe 16 or 8 colors at most per dot, they likely mix colors to create the overall effect of a final color. So I would not expect this method to work on the scale of a single dot.

Alternative ideas to consider would be using the 16 colors available to represent each possible nibble (half byte) and printing 2 dots per byte, possibly resulting in smaller overall prints compared to the 255 color method.. or 8 colors to represent 3 bits at a time.. and so on..use your imagination. You could also use more than one page per file obviously.

Yes its silly for real use but hey, fun project is fun..

Note: use a compression algorithm on the contents of the disk first to shrink it down before converting, thatll save space.. so using the full 720k would be a worst case scenario.

Sup. I like computers. Are you a computer?

Reply 12 of 16, by rmay635703

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11kb per square inch in monochrome can be safely read

In terms of color differentiation, you might get away with 16 colors (4bit) increasing that to 44kb per inch

This is assuming everything lines up correctly

So I guess this could be an “archival” way of backing up floppy disks.

Reply 13 of 16, by torindkflt

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Something kinda like this already exists as a means of "backing up files to paper", I remember reading about it a few years ago.

https://www.extremetech.com/extreme/134427-a- … id-as-it-sounds

It has a very limited capacity though. At 600DPI on a laser printer, the best you could do is about 1MB per page (500KB per side). Advancements in compression & the use of color could improve that further I would imagine, but honestly I don't see it as anything more than a gimmick. It would have no real value in being used as an actual data sharing/transfer medium.

Also, gotta keep in mind that to do this, you need to have a working scanner and a program that knows how to read and decode the (likely proprietary) encoding scheme. It's honestly more trouble than it's worth.

Reply 14 of 16, by spiroyster

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Yes it would be a fun project. But yes would be completely pointless and very fragile as a storage medium.

Maybe avoid colours, while you can pack more data, ink fades... and this can be fast in the right conditions (sunlight). You start off with one colour and before you know it it's faded and then represents a totally different value.

Maybe avoid high dpi precision, data integrity is more important and you would have to work hard enough to preserve it in the first place with a printed medium, however you could use any scanner (most scanners would certainly scan higher dpi than most printers can print) and then post process the image with some very primitive image recognition tools. Fiducial markers (similar to AR calibration markers) on the printed page would help identify orientation and then could provide header information (stride/data range, and even parity bits) so that something reading it would know how to align, but you could use any cheap-ish scanner.... in fact pretty much exactly like QR codes!

720kb is a lot of information though. Maybe a number of A4 pages, depending on how small you make 'bits'.

Reminds me of this gif that did the rounds a few years ago... hello BMP world!
https://stackoverflow.com/questions/5588649/h … microsoft-paint

derSammler wrote:

But anyway, what you are after is called steganography.

This is nothing to do with steganography (nothing is being 'hidden'). That is something completely different.

Reply 15 of 16, by hyoenmadan

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Actually this has actual uses distibuting very small amounts of data in physical form, mostly to distribute initial connection public certificates cryptographic outside the net, like if them were a sort of connection physical "invitation cards". Actually in many places they check for electronic devices like usb dongles to see if you are snooping data to the place/city/country, but they don't check for paper too frequently anymore... Both automated scan devices/dogs. Also certain paper ink is invisible to the standard X-ray devices installed in airports for example.

Reply 16 of 16, by Jo22

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Interesting thread! I'm really surprised by the hefty reactions, however. 😕
The idea is not so new, after all. In The 1980s, when some magazines tried to find alternatives to listings, but disks/tapes were still to expensive,
bar codes were used to store programs on eachs magazine's own paper. At home, the users then would have had to use some sort of lightpen (very simple)
along with a tiny program to "digitize" these blocks of black/white patterns. On the software side, parity bits and check sums were used to make sure data integrity was ok.
Anyway, I'm surprised you apparently haven't heard of this before, considering most of you are likely by decades -err..- -um..- wiser than me. 😜 😉

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