Filesize difference between DVD and CDROM drives - OS2

This is a discussion on Filesize difference between DVD and CDROM drives - OS2 ; I'm not sure why a particular file from a CDROM (it's a mini-CDROM) shows a different file size when read from my Plextor PX-760A, that I recently installed, but smaller on any one of a half dozen CDROM drives on ...

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Thread: Filesize difference between DVD and CDROM drives

  1. Filesize difference between DVD and CDROM drives

    I'm not sure why a particular file from a CDROM (it's a mini-CDROM)
    shows a different file size when read from my Plextor PX-760A, that I
    recently installed, but smaller on any one of a half dozen CDROM
    drives on my other systems. Here's the deal:

    11-03-05 11:59a 2,985,089 0 a--r data1.cab [Plextor 760A]
    versus
    8-25-05 4:05p 2,581,040 0 a--r data1.cab [any other CDROM drive]

    The dates are also different and I don't know why. All the other files are
    of the same sizes reported by each drive, DVD or the CDROMs.

    Opening the differently sized file on each different drive with a hex editor
    seems to indicate that the beginnings of the files are the same, the ends
    of the files are not, but it's not just appended data: it's somewhere added
    in the middle of the file (big files).

    This mini-disk application is, of course, intended for a Windows
    installation. It came with a blood pressure device that stores and
    purports to be able to download several dozens of readings onto a PC.
    [I only got it because it said it could save data in CSV].

    Yet I have another Window's application (ugh!) on CDROM, my Canon
    camera, that checks out fine for file sizes whether it's put in the Plextor
    DVD or one of my CDROM drives. It has a data1.cab file, too.

    Makes my blood pressure go up!

    I thought I'd check here before going on a witch hunt and dismantling
    everything.

    Oh, the Plextor DVD is using "DaniATAPI.FLT", "danis506.add",
    "ASPINKK.SYS", and "ASPIROUT.SYS", while all my other CDROM
    drives are true SCSI hanging off an Adaptec PCI. I think they're all the
    latest as of last week, from Paul Ratcliffe's page and Hobbes.

    --
    Best,
    Erick Andrews
    delete bogus to reply


  2. Re: Filesize difference between DVD and CDROM drives

    Hi Erick

    Erick Andrews wrote:
    > I'm not sure why a particular file from a CDROM (it's a mini-CDROM)
    > shows a different file size when read from my Plextor PX-760A, that I
    > recently installed, but smaller on any one of a half dozen CDROM
    > drives on my other systems. Here's the deal:
    >
    > 11-03-05 11:59a 2,985,089 0 a--r data1.cab [Plextor 760A]
    > versus
    > 8-25-05 4:05p 2,581,040 0 a--r data1.cab [any other CDROM drive]
    >
    > The dates are also different and I don't know why. All the other files are
    > of the same sizes reported by each drive, DVD or the CDROMs.
    >
    > Opening the differently sized file on each different drive with a hex editor
    > seems to indicate that the beginnings of the files are the same, the ends
    > of the files are not, but it's not just appended data: it's somewhere added
    > in the middle of the file (big files).
    >
    > This mini-disk application is, of course, intended for a Windows
    > installation. It came with a blood pressure device that stores and
    > purports to be able to download several dozens of readings onto a PC.
    > [I only got it because it said it could save data in CSV].
    >
    > Yet I have another Window's application (ugh!) on CDROM, my Canon
    > camera, that checks out fine for file sizes whether it's put in the Plextor
    > DVD or one of my CDROM drives. It has a data1.cab file, too.
    >
    > Makes my blood pressure go up!
    >
    > I thought I'd check here before going on a witch hunt and dismantling
    > everything.
    >
    > Oh, the Plextor DVD is using "DaniATAPI.FLT", "danis506.add",
    > "ASPINKK.SYS", and "ASPIROUT.SYS", while all my other CDROM
    > drives are true SCSI hanging off an Adaptec PCI. I think they're all the
    > latest as of last week, from Paul Ratcliffe's page and Hobbes.
    >



    Sounds like the Plextor is mis-reading the CD.

    I think I would start trying to resolve this by checking for a Plextor
    firmware update 1st to see if that helps.

    Regards

    Pete

  3. Re: Filesize difference between DVD and CDROM drives

    On Wed, 18 Apr 2007 21:16:10 UTC in comp.os.os2.multimedia, "Erick Andrews"
    wrote:

    > I'm not sure why a particular file from a CDROM (it's a mini-CDROM)
    > shows a different file size when read from my Plextor PX-760A, that I
    > recently installed, but smaller on any one of a half dozen CDROM
    > drives on my other systems.


    I would suspect some form of anti-piracy mechanism at work. I've had things like
    Microsoft Windows CDs that were impossible to copy because there were some
    differences between the table of contents and the layout of the media (some form
    of deliberate bad sectors are introduced I think) and a copy taken of the disk
    yields an ISO image of a gig or so from a CD of 700MB.

    --
    Trevor Hemsley, Brighton, UK
    Trevor dot Hemsley at ntlworld dot com

  4. Re: Filesize difference between DVD and CDROM drives

    Is it a multi-session CD where the file had been replaced in the 2nd
    session? Then maybe one of your drivers ignores the 2nd session.

  5. Re: Filesize difference between DVD and CDROM drives

    Trevor Hemsley wrote:
    > I would suspect some form of anti-piracy mechanism at work. I've had things like
    > Microsoft Windows CDs that were impossible to copy because there were some
    > differences between the table of contents and the layout of the media (some form
    > of deliberate bad sectors are introduced I think) and a copy taken of the disk
    > yields an ISO image of a gig or so from a CD of 700MB.


    This is another story. MS uses something like hard links on the CD. A
    file is simply referenced twice in the file system tree. If you copy the
    CD this aliasing gets lost and you end up in two (or more) identical
    copies of the same file in different folders. The idea is simply to
    conserve space and reduce redundancies for standard files like runtime
    DLLs (redistributables of the compiler) or so.

    I have never heard that this is forbidden on a CD. But I neither heard
    that it is allowed. However, it works because all references are valid.
    And since the media is read-only it is not very likely to cause major
    problems - except for the one above.

    If you create an ISO image from the CD by reading the track directly
    without the ISO filesystem driver, you can copy this kind of CD without
    problems.

    [F'up to comp.os.os2.misc]


    Marcel

  6. Re: Filesize difference between DVD and CDROM drives

    Sir:

    Guido Hörster wrote:
    > Is it a multi-session CD where the file had been replaced in the 2nd
    > session? Then maybe one of your drivers ignores the 2nd session.

    I was thinking along the same line, like maybe the second session uses a
    different file system, ie. first session uses CDFS aka ISO9660, and the
    second session uses UDF? One way to check may be to use Drives object
    -> properties -> detail and see which file system is reported by each
    device with that CD installed?
    --
    Bill
    Thanks a Million!

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