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Message-ID: <431F266D.3050604@lapo.it>
Date: Wed, 07 Sep 2005 19:42:05 +0200
From: Lapo Luchini <lapo AT lapo DOT it>
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To: "[ML] CygWin " <cygwin AT cygwin DOT com>
Subject: happily messing up with raw devices (aka: lseek problems)
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Hi there.
I'm (trying to) writing a program to configure a GAG boot manager
installation (gag.sf.net) from command line, while trying to create a
program as portable as possible.

I began the developement under FreeBSD, and there I learnt that
/dev/ad0 (FreeBSD's /dev/sda) must be read at 512 bytes block size
(which seems quite natural but, well, I tought the OS would have done
the necessary things by himself, not being overly complicate at all ni
reading and not so complicate in writing too).

Once I got a fairly fuctioning program in FreeBSD I tried it on Cygwin
(as by te way my FreeBSD box does *not* use GAG, so once succeding to
read the wanted sector and printing the string "GAG not detected" I
couldn't really go on).

Under Cygwin, for a change, the problem is in the lseek I use to skipp
the first 4 sectors in order to read the 45th (the one that contains
te actual data I'm interested into).

Is is normal that Cygwin's lseek doesn't work on /dev/sda?
What should I do?
My own personal work-around would be to read all those 44 sectors (and
discarding them), but I don't like that very much, is there some
better/cleaner alternative?

If anyone wants to see the source code, it's all in my Monotone
server, so either
    monotone pull cyberx.lapo.it it.lapo.gagulator
or browse it online:
    http://cyberx.lapo.it/viewmtn/branch.psp?branch=it.lapo.gagulator

    Lapo

PS: why doesn't Cygwin's man include man2 pages such as lseek? =)

- --
Lapo Luchini
lapo AT lapo DOT it (OpenPGP & X.509)
www.lapo.it (ICQ UIN: 529796)
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