IDE disk problem

[Joel]

> [...]
> >>>I have never personally seen problems with drives set to Cable Select on
> >>>a modern machine. 
> 
> Could you please define the word modern in terms of technology and not 
> years ?
> What types of machines you consider modern ? i.e the 2 GHz+ ones ?

The link I posted said something about that, but I don't remember. I
think I used the query "UDMA ATA hard drives" or something similar on
google to find that site, and the first page that came up pretty well
laid out the names of the technologies. You'll have to do some
calculation, however. (Don't think in terms of CPU clock rate, think in
terms of cable data rate -- higher than 33M, I think it was.)

> [...]
> Over here i have two machines . One is a Pentium 166 MMX machine and
> the other one is an AMD Athlon XP 2700+ . Both were build by combining
> parts not as a computer of this or the other brand .
>    All i know is this . The 166 MMX CPU  machine is using non UDMA
> cabling and most probably non Cable Select cables .

That site described some clues you could use to figure out the old
cables.

One odd thing that it pointed out was that the pre-UltraDMA CS cables
put the master in the middle of the cable, so you pretty much had to
hang two drives on it in order to properly terminate the cable.

UDMA cables fix this, locating the master on the end, where it properly
terminates the cable with or without the slave in the middle.

> There i have both
> hard disks configured with the old style by defining Master and Slave .

If that works without generating random data errors under load, I would
guess the cable is not CS. Of course, I could be guessing wrong. I don't
have much hands-on with ATA/IDE hardware. One problem with the "if it
works" approach, you may not be running something that will make the
errors obvious, so you may some time down the road find valuable data
gone awol.

Those pages gave enough information that, if you know how to use a
multimeter, you should be able to test it for CS wiring.

>    In the Athlon XP 2700+  i configured the drives as Master and Slave ( 
> this one
> has UDMA Cables , am unable to identify them as Cable Select ones or not 
> ) because
> that was the working recipe i knew .

Blue connector on one end, gray in the middle, black on the other. Blue
is the motherboard, they said, and black the master.

If I understood them correctly, the UDMA definition requires UDMA cables
to be CS wired.

>    Now i  know for  certain that my Western Digital Hard Disk was sent 
> to me jumpered
> as Cable Select . Now am tottaly unaware about the exact reason Western 
> Digital
> did that , am only certain that it did it .

Again, parrotting pages from the link I posted, manufacturers do that
now because the CS cable standard has been fixed. Previously, the
CS standard was botched badly and took considerable skill to get right,
completely voiding the desired benefits, so no one used it, so
manufacturers ignored it. Now it apparently works.

> IMO it would be preferable >not to use the Cable Select setting even
>   when there is no ambiguity about what the drive realy is .

If you do, be sure to put the master on the end (black), and not in the
middle (gray). The standard says it should allow master in the middle if
you strap the master and slave selects, but I'm betting manufacturers
are not testing their designs (maybe even not sample-testing their
products) for anything but master on the end.

> [...]
> Other than that  i have to thank Joel ( Posting of  13/04/2005 05:53 ,
> possibly GMT+2 timing )

GMT+9 and a lousy MSWindowbox. I'm lazy and posting with a MUA called
Becky that works very nicely in the Japanese environment. It's MSWxxx
only, but at least it doesn't try to run attachments for you.

> for the  very usefull information on Pin 28 .
> I wasn't aware of such information . I bookmarked also the pcguide.com
> site .

Seems to be a good site for this kind of information. I was glad to find
it, too.

--
Joel Rees   <rees at ddcom.co.jp>
digitcom, inc.   株式会社デジコム
Kobe, Japan   +81-78-672-8800
** <http://www.ddcom.co.jp> **