Linux-kernel mailing list archive 1999-37,: Re: ext2 file sizes

# Re: ext2 file sizes

Erik Mouw (J.A.K.Mouw@its.tudelft.nl)
Thu, 16 Sep 99 13:34:21 +0200

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On Wed, 15 Sep 1999 15:17:47 -0400 (EDT), Richard B. Johnson wrote:
> What on earth are you doing with a single _file_ of that size? If you
> need a gob of storage for data acquisition, you might be better off
> with a dedicated raw device. Since you access it in blocks, rather than
> bytes, you won't have a size limitation for a few more years.

Recording studio quality uncompressed digital video (CCIR 601:
720x576@25Hz YUV 4:2:2; ~20 Mbyte per second[1]) for example. One minute of
video already uses ~1.2 Gbyte. It's much easier to record it to a normal
filesystem[2] instead of a raw device: you can use the standard libc file
functions to manipulate the data.

Erik

[1] 720 pixels horizontal x 576 pixels vertical x 2 bytes per pixel + 6144
bytes padding to get to the nearest multiple of 16 kbyte (for
performance reasons) = 835584 bytes per frame.
[2] Although you can hardly call SGI IRIX XFS with real-time partitions
and guaranteed rate I/O a "normal filesystem".

    --
    J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
    of Electrical Engineering, Faculty of Information Technology and Systems,
    Delft University of Technology, PO BOX 5031,  2600 GA Delft, The Netherlands
    Phone: +31-15-2785859  Fax: +31-15-2781843  Email J.A.K.Mouw@its.tudelft.nl
    WWW: http://www-ict.its.tudelft.nl/~erik/

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