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From: Jung-uk Kim <jkim@FreeBSD.org>
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Date: Sat, 20 Feb 2010 01:00:40 -0500
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Cc: Garrett Cooper <yanefbsd@gmail.com>, Tim Kientzle <kientzle@freebsd.org>,
	Juergen Lock <nox@jelal.kn-bremen.de>
Subject: Re: "tar tfv /dev/cd0" speedup patch
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On Saturday 20 February 2010 12:20 am, Tim Kientzle wrote:
> Juergen,
>
> I was looking at your Linux code here and thought
> the technique of trying lseek(SEEK_END) might work.
> Unfortunately, it doesn't: lseek(fd, 0, SEEK_END) gives
> zero for both /dev/sa0 (a tape drive) and /dev/cd0
> (an optical drive).  Are you sure it works on Linux?

Can you please try ioctl(fd, BLKGETSIZE64, &some_uint64_var) or 
ioctl(fd, BLKGETSIZE, &some_u_long_var)?

Jung-uk Kim