TiVo Community Forums Archives - Why no cable select?

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Why no cable select?
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Posted by: sfsutton

Considering that most things I read indicate that the TiVo unit itself, at least 1 disk units, default to the drive being jumpered for cable select, why do all the instructional things (Hinsdale, etc.) always insist that we jumper the drive(s) appropriately to master or slave? Why not just leave them cable select, and connect them to the correct connector on the cable?

Just curious. Having just upgraded my new T-60, which indeed had its 1 drive jumpered for cable select, I was wondering "why bother?".

I did replace the original disk with a single 120MB A drive, and I'll be adding another B drive tomorrow, so really want to know if I need to bother with this.

Couldn't add the B drive today, as my T-60 only had a 2-connector cable, so I've got to drop by Fry's and pick up a cable before I can add 2nd drive.

Cheers,
Steve

Posted by: Merle Corey

Cable select isn't universally recognized - some computers have trouble identifying a CS configured drive. Beyond that, CS often doesn't work very well (or, in many cases, at all) when using two a pair of drives. As a nail in the coffin, for the sake of linux, it's very important to know exactly which drive is master (hda, hdc) and which is slave (hdb, hdd) so that you can use the commands appropriately.

In short, a combination of precision and CYA.

Of course, now some drives have to be set to CS in order to work in a single-drive configuration. (The WD Special Editions do, I would suspect others as well.) It's worth noting that these same drives require master/slave jumpering when used as a pair.

MC

Posted by: Robert S

I've never seen cable select documented, but I assume it works like the floppy cable - a twist in the cable or other change in the connector triggers the master/slave selection.

On the cables that come with a TiVo and standard PC IDE cables, there is no twist - both connectors are identical, so a drive set to CS would be master on either connector, which would make things confusing if you're setting up a twin.

Hinsdale has you connect your new drive as primary slave, so some change of jumper would be necessary anyway. Setting the disk to master definitely sets it to be an A drive regardless of whether there's a B drive or not.

You can see that CS might help TiVo (or whoever) prepare the drives. Presumably they have some kind of specialised disk duplicating machine and the CS settings would let them connect the drives in pairs without having to repeatedly change jumpers.

If you have a two-connector cable in your PC with only one drive on it (CDROM?), you may be able to swap the cables over.

Posted by: Bob

As stated in this post:

AT&Tivo Upgrade Failure

I tried Cable Select on an AT&Tivo and it worked for me.

Just make sure that the two different colored connectors for master and slave are connected to the correct drive!

Posted by: sfsutton

Thanks, folks. 1st I'd heard that cable select was an iffy thing generally. I remember being surprised the 1st time I had a PC and went to add a drive, and ran into the concept. It through me, because I was so used to having to make sure the jumpers were properly placed for master/slave :-) But I never had any problem with any machines after that, using cable select. Which was what prompted me to ask the question.

So in view of:

quote:
Originally posted by Bob
As stated in this post:

AT&Tivo Upgrade Failure

I tried Cable Select on an AT&Tivo and it worked for me.

Just make sure that the two different colored connectors for master and slave are connected to the correct drive!

heck, I can try it both ways tomorrow when I add the 2nd drive. I'll start out with cable select, and see what happens. I'll post back with the results. But I'll probably finish up with the drives hard jumpered - unless, of course, I run into the same type of thing that Bob hit. ;)

Cheers,
Steve

Posted by: sfsutton

Hi,

It just occurred to me that I never posted back like I had promised. Better late than never, I guess.

Anyway, I did the upgrade, which went smoothly, thanks to Hinsdale and all the other folks posting to this forum and writing tools!

I 1st tried with the drives jumpered for cable select, since my T-60 with the original single drive was set that way and worked. However, with the new dual-120GB drives, the machine just hung at the beginning of the boot. Master A drive at the end of the cable, with the slave in the middle.

Turned it off, jumpered the drives to master/slave, and turned it on again, and it worked just fine.

I assume there is nothing special about an IDE cable for cable select - at least, I saw no cables at Fry's that said anything regarding cable select, so I figured any of them would work. If not, then I guess it's possible one could blame the cable for the failure when using cable select. But I don't think that's the case?

Anyway, I'm now a happy owner of at Sony T-60 with "Variable, up to 212 hours" capacity.

Cheers,
Steve

Posted by: Bob

You will have three different colored connectors on the cable.

One color will be master, one color will be slave, and the third color will be to the motherboard.

If your cable has all the same colored connectors, it will not work for cable select.

Posted by: sfsutton

quote:
Originally posted by Bob
You will have three different colored connectors on the cable.

One color will be master, one color will be slave, and the third color will be to the motherboard.

If your cable has all the same colored connectors, it will not work for cable select.

Ok, if that's the case, then my experiment doesn't indicate anything regarding cable select working, or not, on my T-60. The cable I used had all black connectors.

I don't think I'll be going out and buying another cable in order to test cable select, though :) The unit is reassembled, and working just fine, with the drives jumpered, and I believe I'll just leave it that way.

Cheers,
Steve