Date: Thu, 13 Jul 1995 18:37:34 -0400 (EDT) From: John Capo <jc@irbs.com> To: roberto@keltia.freenix.fr Cc: freebsd-hackers@freefall.cdrom.com (freebsd-hackers) Subject: Re: How to enable/disable hardware compression with HP DAT Message-ID: <199507132237.SAA16948@irbs.irbs.com> In-Reply-To: <199507132044.WAA00350@keltia.frmug.fr.net> from "Ollivier Robert" at Jul 13, 95 10:44:14 pm
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Ollivier Robert writes: > > Hello anyone (especially Julian and Peter), > > I just got a new DAT from HP (SureTape 5000, SCSI-2, DDS and DDS-DC > compatible) and I'd like to know how to enable and disable the hardware > compression by software. I guess there is a couple "scsi -c something" > which do the job but I don't know SCSI enough... > > ahb0: reading board settings, int=11 > ahb0 at 0x5000-0x50ff irq 11 on eisa slot 5 > (ahb0:4:0): "TANDBERG TDC 3600 -07:" type 1 removable SCSI 1 > st1(ahb0:4:0): Sequential-Access st1: Tandberg tdc3600 is a known rogue > density code 0x10, drive empty > (ahb0:5:0): "HP HP35480A 1009" type 1 removable SCSI 2 > st0(ahb0:5:0): Sequential-Access density code 0x13, variable blocks, write-enabled > It will be eaisest to disable compression via the option switches. The compression is controlled by mode select page 0x0F according to the docs I have for a HPC1553A which is a drive with an autoloader that holds 6 tapes. Byte 2, bit 7 controls compression. Byte 3, bit 7 controls decompression. A vaule of 1 enables, 0 disables. John Capo
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