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Thread: PUTR OS8 file size limit?

  1. #1

    Question PUTR OS8 file size limit?

    Hello,

    I'm trying to copy an OS/8 PAL source file to an RX01 disk image.
    The file is 65KB. But PUTR complains: " ?output device full "
    But there is enough space on the disk.
    With a bit of testing it seems there is a file size limit of 45KB.
    Sizes below that do copy normal...

    So when I copy a text document of 45KB it appears to be 116 Blocks on
    the RX01 image. Files which are bigger give " ?output device full "

    At first I thought that this might be an OS8 limit. But I have a Fortran
    disk image with a 170 Block library file on it. That should be approx 65KB.
    But when I copy that from the image to my hard disk I get a corrupt file of 3391 Bytes.
    So also reading such a big file from the RX01 images gets corrupted.

    Any ideas about what I might do wrong?

    Regards, Roland
    WTB: Case for Altair 8800 ...... Rolands Github projects

  2. #2
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    Could you use SIMH to read the PAL source like it was a paper tape image and save it on the diskette image?
    Member of the Rhode Island Computer Museum
    http://www.ricomputermuseum.org

  3. #3
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    Isn't there also a limit on the number of files that can be accommodated on a device?

    I also seem to remember that multiple directory entries get used dependent upon the size of the file.

    Or am I making this up?

    Dave

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    45KB (8 bit bytes) is suspiciously close to 32Kw (12 bit words). Don't know if this is just a coincidence.

  5. #5
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    What comes to mind first is that you need the first <EMPTY> block on the file system big enough to hold your output file. Just having enough free space is not enough. OS/8 files must be contiguous. If you have several open spaces the one that will be used will be the first one in the directory and if that isn't large enough...

    If you do an extended directory listing you can see all the <EMPTY> blocks. PIP can squeeze all the empties into one.

    Doug

  6. #6
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    Roland,
    Have had the same issue with PDP1123 and RX02 FFD, Deleted some files and still complaining about disk space.
    Although there was room after deleting some files.
    S
    o something about not completely deleting files.
    If you look you find with DIR <UNUSED> Blok nrs.
    Don't recall how I manage to solve that problem.

  7. #7
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    Quote Originally Posted by daver2 View Post
    Isn't there also a limit on the number of files that can be accommodated on a device?

    I also seem to remember that multiple directory entries get used dependent upon the size of the file.

    Or am I making this up?

    Dave
    From the OS8v3d software support manual page A-3:
    Attached Images Attached Images

  8. #8
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    Don to the rescue again...

    I'd forgotten about the contiguous space as well. It's amazing how many times that has got me in the past with RSX11M...

    There is more to the disk full than the number of free blocks (especially on an '8').

    Dave

  9. #9
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    Quote Originally Posted by daver2 View Post
    Don to the rescue again...

    I'd forgotten about the contiguous space as well. It's amazing how many times that has got me in the past with RSX11M...

    There is more to the disk full than the number of free blocks (especially on an '8').

    Dave
    Now if I could just figure out how to copy and paste an image that does not show up like a postage stamp...

  10. #10

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    Quote Originally Posted by DougIngraham View Post
    What comes to mind first is that you need the first <EMPTY> block on the file system big enough to hold your output file. Just having enough free space is not enough. OS/8 files must be contiguous. If you have several open spaces the one that will be used will be the first one in the directory and if that isn't large enough...
    If you do an extended directory listing you can see all the <EMPTY> blocks. PIP can squeeze all the empties into one.
    Hi Doug,

    Yes I know the files must be at one piece. I've experienced that earlier. But that is not the problem.

    Check this Fortran OS/8 disk image for example:
    https://www.pdp8online.com/pdp8cgi/o...rx01;sort=name

    There is a file FORLIB.RL of 170 blocks. When I copy that from that disk image to my local hard
    disk then I have a corrupted file of 3391 Bytes. So reading AND writing to a disk image gives problems.
    Copying files below approximately 45KB works well in both directions.

    So I don't think it has anything to do with OS/8 but it seems to me that it is an PUTR problem.
    Or I'm doing something wrong off course...??

    Regards, Roland
    Last edited by Roland Huisman; October 9th, 2019 at 07:48 AM.
    WTB: Case for Altair 8800 ...... Rolands Github projects

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