Date: Sun, 22 Jul 2012 23:03:44 -0500 (CDT) From: Robert Bonomi <bonomi@mail.r-bonomi.com> To: freebsd-questions@freebsd.org Subject: Re: fsck on FAT32 filesystem? Message-ID: <201207230403.q6N43iBQ029276@mail.r-bonomi.com> In-Reply-To: <500d2320.f8bzaFvCSay0b7rK%perryh@pluto.rain.com>
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> From perryh@pluto.rain.com Sun Jul 22 22:15:48 2012 > Date: Mon, 23 Jul 2012 03:10:40 -0700 > From: perryh@pluto.rain.com > To: bonomi@mail.r-bonomi.com > Cc: freebsd-questions@freebsd.org > Subject: Re: fsck on FAT32 filesystem? > > Robert Bonomi <bonomi@mail.r-bonomi.com> wrote: > > > MSDOS/PCDOS had -no- O/S functions to directly access actual disk > > devices. The ONLY fuctionality provided to the user, by the "O/S" > > was filesystem based access. To get 'raw' device access, one had > > to bypass the O/S entirely, and use direct BIOS calls (INT 13h). > > FALSE TO FACT. > > MSDOS/PCDOS had no _documented_ functions to directly access the > disks, bypassing the file system, but the functions _did_ exist. I'm sure you can provide the DOS 'function number' for those calls, and cites to published data confirming. > The debugger's "read sector" and "write sector" commands used them, > and I suspect chkdsk, scandisk, and format probably also used them > although I never had occasion to verify one way or the other. My experince in porting MSDOS 3.1 to a non pc-clone architecture was that fdisk, format, chkdsk, debug, and sys all invoked INT 13H directly.
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