POV-Ray : Newsgroups : povray.general : Video Compression : Re: Video Compression Server Time
6 Aug 2024 10:24:25 EDT (-0400)
  Re: Video Compression  
From: Jan Walzer
Date: 24 May 2002 10:26:59
Message: <3cee4db3@news.povray.org>
"Warp" wrote:
> > What ? ... Probably your OS is a bit obsolete
> > 2 gibibyte[1] filelimit is (with an apropriate filesystem, of course) neither a
> > limit under any commercial UNIX, nor under Linux, nor under w2000/XP.
>
>   As Thorsten said, the AVI file format limits its size because it has
> internally hardcoded 4 bytes for expressing the size of the file (of course
> this is braindead because it doesn't only limit the size of the file but it
> also makes the life of the encoder harder because it can't know the size of
> the file when it writes its header, but only after it has created the whole
> file, which means that it must seek again to the beginning to write those
> mandatory bytes, but MS is MS...).

I ever wondered myself, why they have to specify the filesize in the header,
as (IIRC) the data is already written in chunks so the could simply stop
loading/playing thhe file when there's EOF (or a bad chunk) ...
When it happens, that my File has some errors at the end, I still like to watch
the first part I got... this is only possible if the filesize in the header gets
adjusted ... thats so senseless/painful ...

>   As for Linux, yes, it supports files larger than 2 or 4 gigabytes, but only
                                                              ^^-bi ;)
> if you configure it properly. By default the system tools are not compiled so
> that they support files over 4 gigabytes (and there might even be a limit of
                                   ~~
> 2 gigabytes due to signedness) but you have to configure their compiling in
> order to add this support.

Have you tried SuSE-Linux ? [1]

>   Any third-party program which you may want to use will probably not have
> support for files over 2GB (unless they are specifically designed for this)
> because they will probably use the C-standard file handles (which in Linux
> are 32 bits long).
->[1]

>   Also AFAIK the most used file system, ext2, does not have support for files
> over 2 GB.

define "most" `?

if you really mean "Most of all filesystems that ever existed until now and
that are supported by the linux-kernel" then you're probably right.
But if you only consider the Filesystems that are recent and supported by the
distributors or the ones, that are currently "usable" (You know what I mean
by this), you'll see, that the ext2 that you mean (actually there's a
64Bit-patch for ext2[2]) is one of only a few FS that don't support this. The
internal VFS-Layer of the kernel already supports 64Bit since 2.4.0.

So there are really only the tools left, that don't support 64Bit. But:
most of these tools are AFAIK linked against glibc and if these tools
only do simple read/write ops, (They don't need a fileseekpointer) they
wouldn't need recompiling, but only a recent libc (please correct me here,
as I avoid programming C/C++ where I can). So only FS-critical apps need
to be recompiled when upgrading the FS, but wouldn't you normally do so ?

[1] Some call it the Nurembergian Windows because SuSE is located in Nuremberg
    and the installation and usability is luserfriendly like Windows. After boot
    you need three mousclicks until your harddisk gets partitioned and installed
    in the recent 8.0 version ...
    In this standard install it will choose ReiserFS for anything except /boot
    and all the tools are 64Bit-ready ...

    So it depends on your distribution, if you need to recompile your tools
    yourself to use the big filesystems or not...

[2] They used some flags in the FS that were ought to hold ACL-data, but this
    feature never got implemented ...


Post a reply to this message

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.