Date: Wed, 16 Apr 2003 19:57:19 +0300 (EEST) From: Jarkko Santala <jake@iki.fi> To: Andrew Gallatin <gallatin@cs.duke.edu> Cc: freebsd-alpha@freebsd.org Subject: Re: problem with UDMA mode on XP1000 Message-ID: <20030416195422.S316@trillian.santala.org> In-Reply-To: <16029.20850.720877.563791@grasshopper.cs.duke.edu> References: <Pine.OSF.4.33.0304151146380.1028-100000@poptart.bithose.com> <16029.20850.720877.563791@grasshopper.cs.duke.edu>
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On Wed, 16 Apr 2003, Andrew Gallatin wrote: > Jarkko Santala writes: > > On Tue, 15 Apr 2003, Jameel Akari wrote: > > > > > I had the same sort of problem in an Alpha PC164, but in the end > > > the onboard IDE was so terrible and Tru64 refused to run a hard disk on > > > it, so I bought an ISP1040 and went SCSI, and it's been solid. > > > > Well, I don't think it's that terrible: > > > > dd if=/dev/zero of=foo bs=1m count=100: > > ad0: 104857600 bytes transferred in 6.863760 secs (15276991 bytes/sec) > > da0: 104857600 bytes transferred in 8.200968 secs (12786003 bytes/sec) > > > > atapci0: <CMD 646 ATA controller> port 0x10180-0x1018f irq 5 at device 11.0 on pci0 > > ad0: 117246MB <Maxtor 4G120J6> [238216/16/63] at ata0-master WDMA2 > > FWIW, WDMA2 is not safe as there is no CRC checking. I've seen > corrupted (random, infrequent single bit errors) files when running a > PC164LX with an ata drive in WDMA2 mode. The higher modes (UDMA33 ..) > get you CRC checking. As soon as we noticed the corruption, we moved > the box to SCSI. I suppose no checking explains the performance. ;) But good to know anyway. Any reason why it gets enabled by default if its not safe? -jake -- Jarkko Santala <jake@iki.fi> http://www.iki.fi/~jake/ System Administrator 2001:670:83:f08::/64
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