Floppy Disk Capacity

What is the capacity of a 3.5" floppy? Isn’t it 1.44 Meg? If so, then how is it that my digital camera’s teeny-weeny disk is 8 Meg? My wife and I are arguing because she swears my sister’s digital (which uses a 3.5" floppy disk) holds many more photos than our 8 Meg teeny-weeny disk.

I’m hoping some Doper can set this dope straight!

  • Jinx

You are correct, the capacity of a floppy is 1.44 MBs. It is all relative though, your camera probably takes pictures at a much higher quality than your sister’s. You can (and your sister can too) change the quality at which the cameras save pictures at. For example; I have a Sony Mavica FD-91 which uses floppies. At the highest quality (excluding .bmp), I can get about 8 or 9 1024 x 768 pictures on a single floppy. The full sized images run about 150 kb each. If I change the settings so I am only saving at 640 X 480, I can fit many more (something like 35-40) pix on a floppy - but the quality goes way down.

I also have a Sony DSC-S85 digital camera. It saves at 2272 x 1704, and each image runs about 2 MBs each. So I can fit about 8 on my 8 MB memory stick. But the quality of each picture is far superior to any I can take with my Mavica, simply because it stores more information in the larger sized files.

So in a nutshell, it all depends on how much quality you want - I want all the quality I can get, so I prefer to take my pictures at the highest settings possible - and invest in more memory sticjk space.

Ack - chang the line that reads “So I can fit about 8 on my 8 MB memory stick” to “So I can fit about 8 on my 16 MB memory stick” pleas. I currently have 3 Memory sticks: a 16 MB, a 64 MB and a 128 MB.

I think you’re refering to Smartmedia storage. They look like little floppy disks (unlike CompactFlash, they’re bendable) but they are totally different. They’re solid state memory. And they now can hold as much as 256 Meg!!

They make drives that can write 30MB to a standard 3.5" floppy disk. Needless to say, you need to use the same type of drive to read the disk again. They also make “floptical” drives that can read floppies AND special disks that can store up to 200MB.

“Floptical” is now my new favorite word. Thanks!

The floppy drive at 1.44mb is very old tech that for some reason has stalled. They could make higher capaciuty floppies but it is largly outmoded by now. The 1.44 standard was around since the 286 or at least the 386 chip (perhaps earlier) when harddrives weren’t even as big as the memory on some of those smartmedia sitcks.
The reason that more pictures can fit onto that floppy is that (as pointed out) the quality is not as good. The cameria designed around a floppy as storage has a limit on 1.44m so the manuf. will allow you to store a decent amount of picts on that type of disk as no one would buy a cameria that will only allow 1-3 shots per disk.

IIRC jpg compression (the type most dig. camerias use) has a few tricks to reduce file size - all of which degrade the image. The will not display all the colors (using diffrent intensities of the same color instead of different colors to fool the eye), also they will reduce the reslution out towards the edges where you are typically not looking.

Add to this the resolution of the cameria and you have many variables to play with to reduce file size at the expense of quality.

btw the smart media is not all tha flexible. You can bend it slightly but it is very stiff and feels like it might break if bent too much.

1.44 MB is the formatted capacity, and that assumes an MS-DOS (PC) format. I don’t know about the PC universe, but on the Macintosh (back when we had floppies :)), that formatting scheme was called MFM. Our low-density format was different from yours–the PC low-density format was 720 K (half of 1.44 MB) but the Macintosh low-density format was 800K and it was GCR formatting rather than MFM. A hi-density GCR scheme (which was never used) might have put 1.6 MB on a floppy.

Nor was the Mac’s GCR format the most efficient format going. The Amiga put 880K on a low-density disk in native Amiga format (whatever that scheme might have been called). By extrapolation, that scheme might have put 1.76 MB on a hi-density diskette.

Wow, memory lane! Yeah, I used to have a SCSI Floptical on my Mac SE. It wasn’t a 200 MB device, though, it was a 21 MB device. (It did indeed also read and write to 720K and 1.44 MB floppies). I sort of assumed that the Floptical had gone extinct back when SyQuest was battling it out with Iomega. The cost of those 21 MB special optically-tracked floptical diskettes was close to the cost of a SyQuest cartridge 10 times its capacity. Did they really come out with a 200 MB version of the floptical?

I’d like to know more about how 30 MB is stored and retrieved on a plain old 3.5" non-optical unenhanced floppy. Not to cast aspersions on your veracity but that sounds farfetched.

FYI, some unix systems (AIX) and IBM PCs use 2.88 mb floppies but again the real answer to your question is, as others have mentioned, the fact that the technologies involved are completely different. I bought my wife a digicam with a 64 mb smartmedia chip. There’s about the size of a postage stamp and not much thicker. Way cool. You can buy an adapter that allows you to plug this chip into a floppy drive to read the images onto your pc. Many cameras also have USB ports so you can plug the camera directly to your pc and d/l images. I wouldn’t waste money on floppy drive any more.