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Thread: Magical hidden 40K of space on 1.44MB floppies or pure snake oil???

  1. #1

    Default Magical hidden 40K of space on 1.44MB floppies or pure snake oil???

    So I was perusing some old freeware/shareware collections and ran across a program that promises access to a hidden 40K of space on 1.44MB drives. From the readme:

    Code:
    Extraterrestrial Floppy Magic (ET.EXE) for DOS and WINDOWS ver 1.0
    ===================================================================
    This program uses an undocumented "extraterrestrial" area on a floppy disk 
    (1.44 MB only) to store files. This program can store any file provided it's
    size dosenot execeed 40941 bytes. The main advantages are:
    1. This area provides an additional storage space of 40941 bytes on the floppy.
       This  storage  space is available even  when there are  0 bytes  free on the
       floppy.
    2. Any existing data/information stored on the floppy is left untouched.
    3. Files  are so 'firmly'  stored, in  this "extraterrestrial" area,  that they
       are not removed or deleted even if you completely FORMAT the floppy!
       
    Some more information about the "extraterrestrial" area
    --------------------------------------------------------
    This area is a totally  undocumented area  and is  not used or  accessed by the
    operating system. This area cannot be accessed even by utilities such as Norton's
    DISKEDIT. In fact, I have not come across any program (other than ET.EXE ofcourse)
    that uses  or  accesses this area. Some  people have  used this area to prepare
    seemingly invincible Key Disks.
    Anybody know what the author is talking about or is this some of that old timey shareware snake oil?
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions MatchPoint AND/OR UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!

  2. #2
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    That figure is almost exactly what you’d expect if all it was doing was formatting two additional tracks with 20 sectors a side instead of the usual 18. Sticking data on tracks 81-82 would easily explain why it would survive a regular Format as well.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

  3. #3

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    I second that. Would also fit in with the author calling it "extraterrestrial" (beyond the 80 tracks).

  4. #4
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    There are various ways to squeeze more storage out of a floppy disk. The more common way is to reduce the gap between sectors (which increases the chance of drive speed variance clobbering neighboring sectors during write) and adding extra tracks. If you happened to have a BIOS (Some 8-bit HD FDCs) or OS (Win9x DOS) that supported it, you would not even need an extra driver loaded. Various tools like FDFormat, Nformat, Maxiformat, and so on could do that.

    A typical 1.44mb disk could hold about 1.8mb that way, a 1.2mb disk could get about 1.5mb, a 360k disk could get 420k. A 360k DSDD disk used in a 1.2mb drive could get up to a whopping 830k if it was formatted using 80 tracks instead of 40.

    Programs that required extra tools to use or drivers to be loaded were a bit less desirable. It sounds like this program takes a normal 1.44mb disk and makes the extra tracks look like an additional drive. IBM used an ~1.9mb "XDF" format to distribute software that normal DOS could not read. Microsoft used a ~1.7mb "DMF" format to distribute software, but under Windows 9x you did not even need a bios patch to read it. Chuck as mentioned a tool that could use the unused odd numbered tracks on a 360k disk in a 1.2mb drive to make it look like TWO 360k disks. Another weird fact, due to head alignment, it is even possible to flip over a "flippy" 5.25" disk and get access to a couple more tracks that don't get clobbered by a double sided drive.

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    Let the program run on a disk and see what it actually does. I think Anadisk should be able to check if extra tracks were used.

    My favorite of the extra storage on a floppy techniques used the 300 kbps mode on a 3.5" DSDD to store 960 kB instead of the standard 720 kB.

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    Recall that, before MSDOS, many CP/M systems stored 10 512 byte sectors on a "720K" disk, giving 800K. HP 150 formatted disks typically added an extra "short sector" to each track. Never did figure out why that was done, as MSDOS never used it.

  7. #7

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    So sounds like snake oil i.e. he did not find or do anything that wasn't already being done. I am aware of the special formatting tools out there to get extra capacity out of floppies (my personal favorite is 2M). However, those tools were contemporaneous with this one so I was wondering if he was doing something different since the "area is a totally undocumented area" and he has "not come across any program (other than ET.EXE ofcourse) that uses or accesses this area."
    Current Wish List: 1. IBM 7531 Industrial Series PC 2. NEC MultiSync XL (JC-2001) Monitor 3. MicroSolutions MatchPoint AND/OR UniDOS card 4. Compaq 14" VGA CRT Monitor (the one that came with the SystemPro). 5. Stacker HW CoProcessor Board MCA BUS. If you have any of the above for sale please PM me. Thank you!

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    Quote Originally Posted by Shadow Lord View Post
    I was wondering if he was doing something different since the "area is a totally undocumented area" and he has "not come across any program (other than ET.EXE of course) that uses or accesses this area."
    It does pretty much sound like he's full of it. I used to use the 82 track formatting capabilities of 2M back in the day and I don't think I ever ran across a drive that couldn't handle it, so this was definitely not any kind of secret revelation. Unless you have a specific need to stash some data on a disk where it won't easily be found without the matching device driver/access program (I'm sure this could have been super useful for industrial espionage and whatnot?) there are far better ways to eek a few more dozen K out of a floppy disk.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

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    The program does sound like it is formatting the extra tracks while leaving the existing 80 tracks formatting alone which is something unusual. Not unprecendented, the Soviet One Track System made the disk format look like a standard 720k but put the OS on the 81st track maximizing data storage. I think there was even a tool similar to SYS to add the boot track to an already formatted disk.

  10. #10
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    Those tracks are "undocumented" in the sense that floppy drive vendors didn't include those in their specifications and the actual max track can be different between two seemingly identical drive models.

    I seem to recall that the 3.5" citizen drive in my Kaypro 2000 would not step beyond the 80th track, although that may have been BIOS stopping it. As far as I know, anything beyond the 80th track is just there as a mechanical margin for error.

    Quote Originally Posted by Chuck(G) View Post
    HP 150 formatted disks typically added an extra "short sector" to each track. Never did figure out why that was done, as MSDOS never used it.
    I've wondered about that. I've seen that in some HP 150 disk images, figured that was a holdover from something.

    If that sector were stripped out, would the disk image still work fine on a real machine?

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