From owner-freebsd-stable Thu Feb 1 9:49:10 2001 Delivered-To: freebsd-stable@freebsd.org Received: from msgbas1t.cos.agilent.com (msgbas1tx.cos.agilent.com [192.6.9.34]) by hub.freebsd.org (Postfix) with ESMTP id 9C7BE37B69C for ; Thu, 1 Feb 2001 09:48:49 -0800 (PST) Received: from msgrel1.and.agilent.com (msgrel1.and.agilent.com [130.30.33.104]) by msgbas1t.cos.agilent.com (Postfix) with ESMTP id EDE09591 for ; Thu, 1 Feb 2001 10:48:48 -0700 (MST) Received: from mina.soco.agilent.com (mina.soco.agilent.com [141.121.54.157]) by msgrel1.and.agilent.com (Postfix) with ESMTP id 08687184 for ; Thu, 1 Feb 2001 12:48:48 -0500 (EST) Received: from mina.soco.agilent.com (darrylo@localhost [127.0.0.1]) by mina.soco.agilent.com (8.9.3 (PHNE_18979)/8.9.3 SMKit7.1.1_Agilent) with ESMTP id JAA24803 for ; Thu, 1 Feb 2001 09:48:47 -0800 (PST) Message-Id: <200102011748.JAA24803@mina.soco.agilent.com> To: stable@FreeBSD.ORG Subject: Re: ast0: TAPE Reply-To: Darryl Okahata In-Reply-To: Your message of "Thu, 01 Feb 2001 18:33:11 +0100." <200102011733.SAA66640@freebsd.dk> Mime-Version: 1.0 (generated by tm-edit 1.6) Content-Type: text/plain; charset=US-ASCII Date: Thu, 01 Feb 2001 09:48:46 -0800 From: Darryl Okahata Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Soren Schmidt wrote: > Another thing is that for this to work, the drive has to be set into > a 32.5Kb block mode where the 32K carry userdata, and the 512bytes > carry block info, like blocknumber etc, since you have to have > that info when reading, since you must keep track of which blocks > you have read, since they might be repeated later due to bad spots > and the above hit'n'write strategy left one double block around... > > So, since I have not found a way to deal with this in a satisfactory > way (malloc'ing 1 Mbyte worth of buffer in the kernel is not fun), the > support we have can't handle tapes with bad spots on it... Does the ata device have something analogous to the SCSI passthrough device (e.g., /dev/pass0)? A long time ago, when I was looking at implementing a "driver" for the SCSI version of the Onstream drive, it was much easier to write a userland "driver" that used the passthrough device. This way, you can malloc() as much space as you want (the real reason I did it that way, was because it could be much easier to port to other operating systems). -- Darryl Okahata darrylo@soco.agilent.com DISCLAIMER: this message is the author's personal opinion and does not constitute the support, opinion, or policy of Agilent Technologies, or of the little green men that have been following him all day. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message