Date: Wed, 6 Jun 2007 14:34:55 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Takanori Watanabe <takawata@init-main.com> Cc: freebsd-geom@freebsd.org Subject: Re: Flash memory like geom class. Message-ID: <20070606123455.GE1121@garage.freebsd.pl> In-Reply-To: <200706061155.l56BtHSY019405@sana.init-main.com> References: <200706061155.l56BtHSY019405@sana.init-main.com>
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--AjmyJqqohANyBN/e Content-Type: text/plain; charset=iso-8859-2 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jun 06, 2007 at 08:55:17PM +0900, Takanori Watanabe wrote: > Hi, I wrote flash memory like geom class backed > by kernel memory. >=20 > It emulates 4MB capacity, 512bytes block size and 16KB erase size flash m= emory. > The device is initialized with 0xff. > When you write a sector to the device, the content will be gets and opera= tion=20 > with current sector content and the data provided. >=20 > When BIO_DELETE operation is issued, the times is counted per region > and fill the erase region with 0xff. >=20 > http://www.init-main.com/geom_pflash.tar.gz > Current issues I have is as follows. >=20 > 1.How can I issue BIO_DELETE from userland? > I convice BIO_DELETE is used to perform erase operation to flash, > but I could not find a way to issue BIO_DELETE from userland. > Or BIO_DELETE is not suitable request for it? I recently exteneded libgeom to support g_delete() function, which does what you want. You may also use DIOCGDELETE directly (also added recently). > 2.How can I export statistic information? > I record the count of erase operation, but there is no way to > export the information for now, other than poking with=20 > debugger. How shall I do with it? I'd guess sysctl or if you want them to be per-provider you should geom geom_ctl. Check out g_nop.c and how it exports various statistics in g_nop_dumpconf() function. > 3.Do you think it something useful? > I think it can be used to develop flash file system. > How do think about this? I haven't looked at the code yet, not thought about this, just wanted to provide some info, so I can't comment on its usefulness yet. --=20 Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --AjmyJqqohANyBN/e Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (FreeBSD) iD8DBQFGZqnvForvXbEpPzQRAlUzAKCPgX51QzgB4JVFFonSvli6AChMFgCeLu9c meAzjxOXUWhRxw/2zvB5HxI= =iZsS -----END PGP SIGNATURE----- --AjmyJqqohANyBN/e--
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