I have an PC with mfg date of 5/2003 and the motherboard manually has warning note about separating the cdrom drive to the secondary IDE controller because it will force the IDE controller to step down the max speed to the slowest device. This was not only for cdrom drives but also mixing UDMA100 and UDMA66 and UDMA33 disk on any IDE controller. IDE max controller speed is set by bios at boot time after the probe post process completes. So just exactly what time period are you referencing by "With today's computers"? DO you work for Bios chip manufacture, or write the FBSD bios's boot probe code? What is your technical background to make such an authoritative statement in light of so much information to the contrary?
Now on the subject of which end of the IDE ribbon you plug into the motherboard. I agree with you that it makes no difference other that one end has 2 nipples closely spaced together and if that end is plugged into the motherboard it's next to imposable to attach an second device to the ribbon. Now if the devices are jumper as master and slave it does make an difference which of the 2 closely spaced nipples are used as the nipples have default meanings. And I believe the default nipple meaning (IE: master, slave) changed from the UDMA33 of the ending nipple being master to middle nipple being master for UDMA66 & 100. Now I am no technical wizard, but that has been me experience as new PCs have replaced older ones in the company I work for and I have had to configure them before giving them to the users. Now the work PC all rum ms/windows and I can see the 'post' summary display shows the UDMA of 33 on both devices when I have an UDMA100 hard drive and UDMA33 cdrom on same IDE controller. The hard facts just do not match you generic statement. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Jonathan Arnold Sent: Friday, February 13, 2004 9:59 AM To: [EMAIL PROTECTED] Subject: Re: Why would drive run at UDMA33? (Segate 80GB) (Still going through some old messages, but this thread had some misconceptions and myths that I'd like to straighten out): > ATA channel 0: > Master: ad0 <ST380021A/3.19> ATA/ATAPI rev 5 > Slave: acd0 <CD-RW 24X10X40/Y.IW> ATA/ATAPI rev 0 > ATA channel 1: > Master: ad2 <ST380011A/3.06> ATA/ATAPI rev 6 > Slave: no device present > > Here is your problem. On channel 0 You have an UDMA100 disk and an > UDMA33 cd-rw. The motherboard IDE controller steps down the speed to > the speed of the slowest device. You have to move the cd-rw device This is not true. With today's computers, all disks will operate at their highest speed, not matter what other device they are paired with. Their transfer rate may be slowed down if *both* devices are accessed at the exact same time, but that's nothing to worry about generally. So just because you have a CD-ROM and an UDMA100 disk on the same channel, it doesn't mean the UDMA100 disk will be slowed in nearly any noticable fashion. Also mentioned in this thread was something about the cable being connected "backwards". There is no "motherboard" and "disk" connecting direction in an IDE cable, be it a reguler one or a UDMA 100 one. Cables are made to be a little more convenient if you hook them up the "right" way (with two connectors closer together at one end), but it has no bearing on the speed or the UDMA detected. -- Jonathan Arnold (mailto:[EMAIL PROTECTED]) Daemon Dancing in the Dark, a FreeBSD weblog: http://freebsd.amazingdev.com/blog/ _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]" _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"