From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Reed Subject: Re: SCSI tape block size Date: Thu, 28 Sep 2006 09:34:44 -0500 Message-ID: <451BDD84.2060704@sgi.com> References: <200609241605.32327.johna@onevista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from omx2-ext.sgi.com ([192.48.171.19]:65422 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S1161153AbWI1OfC (ORCPT ); Thu, 28 Sep 2006 10:35:02 -0400 In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Guennadi Liakhovetski Cc: linux-scsi@vger.kernel.org Guennadi Liakhovetski wrote: > Hi all > > I've got a problem report and a patch from John Adams, he says tmscsim > driver under 2.6.17 and on doesn't allow him to read tapes with blocksize > of 1MB. He fixes this with the below patch. > > On Sun, 24 Sep 2006, John Adams wrote: > >> --- drivers/scsi/tmscsim.c.bak 2006-09-24 12:55:08.000000000 -0400 >> +++ drivers/scsi/tmscsim.c 2006-09-24 12:55:56.000000000 -0400 >> @@ -2300,7 +2300,8 @@ >> .this_id = 7, >> .sg_tablesize = SG_ALL, >> .cmd_per_lun = 1, >> - .use_clustering = DISABLE_CLUSTERING, >> + .use_clustering = ENABLE_CLUSTERING, >> + .max_sectors = 2048, >> }; >> >> /*********************************************************************** > > It looks like > > 1) use_clustering doesn't directly affect maximum block size, so, he > doesn't really need it, although, it might make sense for tmscsim to > improve performance. > > 2) max_sectors is indeed what he needs, but it looks strange that now it > has to be set by the low-level driver... For block devices you can set it > at run time with /sys/block/sda/queue/max_sectors_kb, right? But what > about tapes? Thank you for posting this. I was wondering why with 2.6.16 the maximum tape block I could access via by BusLogic adapter dropped to 64k. Now I know what to change. Does anyone know what the appropriate max sectors limit is for BusLogic? Thanks, Mike > > Sorry, didn't find too much documentation about it. > > Thanks > Guennadi > --- > Guennadi Liakhovetski > - > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > >