From owner-freebsd-hackers Thu May 2 11:18:05 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id LAA14689 for hackers-outgoing; Thu, 2 May 1996 11:18:05 -0700 (PDT) Received: from linux4nn.gn.iaf.nl (root@linux4nn.gn.iaf.nl [193.67.144.34]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id LAA14666 for ; Thu, 2 May 1996 11:18:00 -0700 (PDT) Received: from uni4nn.iaf.nl (root@uni4nn.iaf.nl [193.67.144.33]) by linux4nn.gn.iaf.nl (8.6.9/8.6.9) with SMTP id UAA11424 for ; Thu, 2 May 1996 20:18:24 +0200 Received: by uni4nn.iaf.nl with UUCP id AA12481 (5.67b/IDA-1.5 for FreeBSD-hackers@freebsd.org); Thu, 2 May 1996 20:18:08 +0200 Received: by iafnl.es.iaf.nl with UUCP id AA11677 (5.67b/IDA-1.5 for FreeBSD-hackers@freebsd.org); Thu, 2 May 1996 19:57:31 +0200 Received: (from wilko@localhost) by yedi.iaf.nl (8.6.12/8.6.6) id UAA01622 for FreeBSD-hackers@freebsd.org; Thu, 2 May 1996 20:01:19 +0200 From: Wilko Bulte Message-Id: <199605021801.UAA01622@yedi.iaf.nl> X-Organisation: Private FreeBSD site - Arnhem - The Netherlands Subject: using DLT drive on FreeBSD To: FreeBSD-hackers@freebsd.org (FreeBSD hackers list) Date: Thu, 2 May 1996 20:01:19 +0200 (MET DST) X-Mailer: ELM [version 2.4 PL23] Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Hi there I 'found' myself a DEC TZ87 DLT drive destined for the scrapyard. This is a 10/20Gb device (the 20Gb is using the optimistic 2:1 compression). Quantum calls this a DLT2000. Apart from solving my backup needs for the foreseeable future :-) I also have a few questions: First of all, the drive works just fine on my Asus P90/NCR810 The main problem is that I cannot set the buffersize used by 'dump' to a high enough value to keep the tape streaming. These puppies need 1.3 - 2.5 Mbyte/second to keep streaming OK. The actual required rate is dependent on how good the data compresses. An experiment @ work with a Sun Sparc20 revealed a 1.9Mbyte/second transferrate while dumping the /usr Solaris filesystem. Side note: I had to put the drive on a seperate SCSIbus/adapter to make this work. I think the 2.1R limit is 32kbytes. In the recent past there was a discussion about this on this list (in relation to DAT drives??). Didn't pay too much attention at the time because I did not have the drive then. Is there any way to increase this value (seem to remember there was not.?) It is of course also possible that the HD & tape being on the same NCR810 are hurting the streaming operation. NB looks like I also have to hack a bit into 'mt' to allow the density/ compression settings to work. WIll dig up the device spec to see what that has to say Comments? Wilko _ __________________________________________________________________________ | / o / / _ Wilko Bulte email: wilko@yedi.iaf.nl |/|/ / / /( (_) Private FreeBSD site - Arnhem - The Netherlands --------------------------------------------------------------------------------