Date: Thu, 25 Oct 2001 12:19:13 +0200 From: Erik Trulsson <ertr1013@student.uu.se> To: Nils Holland <nils@tisys.org> Cc: freebsd-questions@freebsd.org Subject: Re: UDMA66 - One cable, two modes? Message-ID: <20011025121913.A5846@student.uu.se> In-Reply-To: <20011025115305.E240-100000@howie.ncptiddische.net>; from nils@tisys.org on Thu, Oct 25, 2001 at 12:00:43PM %2B0200 References: <20011025115305.E240-100000@howie.ncptiddische.net>
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On Thu, Oct 25, 2001 at 12:00:43PM +0200, Nils Holland wrote: > Hi all, > > reading through my /var/log/messages I just noted something that caught my > attention because it seems strange to me. Have a look at the following any > pay attantion to the two hard disks on ata0: > > Oct 24 15:56:31 howie /kernel: ad0: 12416MB <WDC AC313000R> [25228/16/63] at ata0-master UDMA66 > Oct 24 15:56:31 howie /kernel: ata0-slave: DMA limited to UDMA33, non-ATA66 compliant cable > Oct 24 15:56:31 howie /kernel: ad1: 8063MB <FUJITSU MPE3084AE> [16383/16/63] at ata0-slave UDMA33 > Oct 24 15:56:31 howie /kernel: acd0: CDROM <ATAPI CDROM> at ata1-master using PIO4 > Oct 24 15:56:31 howie /kernel: acd1: CD-R <CR-4801TE> at ata1-slave using PIO3 > > What does this tell us? Well, the primary master, a Western Digital hard > disk, is correctly initialized to use UDMA66. However, the primary slave, > which is a UDMA66-compliant drive made by Fujitsu is only using UDMA33. > That is justified by the message saying that the ata0-slave cable is not > UDMA66-complaint. > > Now ... how can that be? The cable to which both of these hard disks are > conencted is the same one, as both are connected to the primary port. So, > how can the first drive work at UDMA66, while the slave complains about a > non-compliant cable? > > The only thing that comes to my mind trying to explain this is that it's > probably not the cable causing the problem, but the IDE controller on the > mainboard. Still, any comments on this are welcome! If you want to use UDMA66 you are not allowed more than one drive per cable. It is the fact that you have two drives connected to the same cable which makes the cable not UDMA-66 compliant. This is not FreeBSD specific but rather an effect of how ATA works. If you want to run both drives at UDMA-66 speeds you will have to get an extra controller. -- <Insert your favourite quote here.> Erik Trulsson ertr1013@student.uu.se To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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