How to add a slave drive

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Created: 16 Apr 1998 ::: Last updated: 07 Aug 2007

Applies to:   Win95   Win98   WinMe   Win 2000/NT   WinXP   WinVista   MacOS

Keywords: computer, upgrade, add, , slave, drive, SCSI, IDE, jumper, installation, second, hard, drive

By Andy Walker

Question: I have two Quantum ProDrive ELS 120 Meg hard drives that I salvaged from a couple of Compaq Deskpro 4/66i's. Neither unit has the recognizable jumpers to make one a master and the other a slave. Compaq support told me that they cannot be configured together, but I think that somewhere someone has done just that. The jumpers that do exist on the hard drives are labelled "SP", "DS", and "CS", in that order. The jumper connector is on "DS". I have tried every combination, and the CMOS gets set-up properly for drives C and D, but only one drive is recognized and that is only when the connector is on "DS". What should I do? —Rob

Answer: This question seems surprisingly complex, but it really isn't. Why not? I'll let you in on a TechnologyTips trade secret in just a few paragraphs.

First an explanation, then the answer:

Jumpers on hard drives, for the uninitiated, are usually tiny little sliders (often black) that slip over two wire prongy things to connect them. They can usually be found on the back or side of a hard drive casing.

Depending on which prongy pair you slide a jumper over often determines how a piece of hardware is configured. When you install two drives, you have to set one as a master drive and the other as a slave. The computer looks for the operating system on the master drive and uses the slave as a secondary drive that behaves as storage.

All IDE hard drives I've encountered have them. IDE, by the way, is Integrated Drive Electronics. Enhanced IDE or EIDE drives are the types of hard drives you're most likely to encounter. SCSI, which is pronounced "scuzzy", is the other kind. That's "Small Computer System Interface."

All right, on to the problem: While we're on the topic of acronyms, here's a breakdown of what you see on your Quantum drive jumpers. DS means "drive select" and is used to set the drive as master. SP means "slave present" and sets the drive to slave. It is used when another drive is set to DS. CS is "cable select". CS is only used in systems that support the cable select feature. Cable Select allows for each IDE disk drive to be jumped the same. Their position on the cable determines the drive ID. This requires a special cable, and both drives on the interface have to support this feature for you to be able to use it.

Despite all this fascinating acronym-busting, these typical instructions for Quantum drives don't apply to your problem. When you're configuring a Quantum ELS drive, skip the SP jumper altogether on the slave.

An index on the retired Quantum ProDrive ELS 120 hard drive specifications can be seen at this web page.

Now for the trade secret. The question seemed tough, but it took me five minutes to figure out. How? I searched for "Quantum" and "hard drive" on at Yahoo! Three clicks, and I had the information. It's not always that simple, but 90% of the time, the technical information anyone might need for almost any computer question is available right on the web. The other 10% can usually be found via email or phone.

Those resources are usually on a company's web site. Quantum prefers the phone. Their toll-free support in Canada and the U.S. is available at 1-800-284-5101. Fax-back support is at: 1-949-725-2176. You can also visit their "self-service" customer support page —you should find a link to their Email Support as well as other choices.

TechnologyTips Notes: While we're on the topic of hard drives and installation of two at a time, I came across a bit of a problem recently when I helped my dad install a second hard drive into his IBM Aptiva. There we were, father and son, on a Saturday, up to our elbows in computer guts. The second hard drive was mounted in the available bay, the jumpers were all set correctly, and we were ready to connect the drives up, when we realized that there was only one power cable coming from the power source and we had two drives that needed power. When I operated on my machine at home, it had an extra power cable for a secondary hard drive so I didn't think it'd be an issue. What are a boy and his father to do? I zipped out to the computer store. They stocked a generic $17 "Y" power cable. It splits the cable so both drives could be plugged in. Thought I'd pass the tip along.
If you can wait a couple of days, why not visit a site like TigerDirect , buy the part online and have them deliver it to your home?