Basic Guide to EIDE Drives
The aim of this article is to provide you with some basic information about the E-IDE channels in your computer and how you can add new drives such as Hard Drives and CD-ROM drives to them.
What is EIDE?
EIDE stands for Enhanced Integrated Drive Electronics. It is a new standard of the IDE standard developed by Western Digital. Its supports a maximum transport speed of 16.6MBps. There are also new standards for EIDE, known as Ultra ATA which support speeds of upto 33MBps.
The EIDE Channels
Most motherboards these days come with two EIDE channels, each channel supporting up to two devices. This means that you can have a maximum of four EIDE devices installed in your system at any one time.
You connect EIDE devices to via an EIDE Ribbon Cable. These cables are flat and grooved, with three connectors on them. One connector plugs into one of the EIDE channel slots on the motherboard, and the other two connectors connect directly to the port on an EIDE drive.
You can also get EIDE ribbons in special, rounded versions now which are designed to improve the airflow in your computer as they have a smaller overall mass. The two types are displayed below:
When one of the devices is in use on an EIDE channel, that channel is tied up and the other device will not be accessible until the devices activities have finished.
Drive Designation
When people talk about installing additional hard drives and CD/DVD drives, a common term you will hear is Master and Slave device. These terms relate to how a device is connected to the EIDE channel on the motherboard. When you have two devices on one EIDE channel, one MUST be setup as the Master device, and the other MUST be setup as a Slave device.
Assigning Drive Designation
To assign whether the drive unit acts as the Master Device, or the Slave device on the EIDE channel, you have to manually set a jumper at the back of the unit. A Jumper is a small plastic block that you use to cover, (short) two pins on the drive unit and tell the device what it should act as.
Jumpers on Drive units usually have three settings:
- Master
- Slave
- Cable Select
The first two options have already been explained. Cable Select will be explained in a minute.
Unfortunately, there is no standard in how pins are assigned on drives. Each drive can be different. Some drives have 9 pins, where some have 10-11 and each unit may require the jumper to be placed in a different ways. For example, on one Hard drive - to enable master you may have to cover pins 1 and 2 vertically, where as on another hard drive - you may have to cover pins 8-9 to enable master. You should refer to your documentation for your drive for setting the jumper.
Most drive units these days will indicate the jumper settings themselves, either in the form of a diagram on the top label, or by letters molded into the plastic around the jumper pins. Some drives will even require the use of two jumpers, like the one in the image below.
An example of an EIDE hard drives jumper configuration.
Cable Select
Cable Select is the third option available on a lot of drives, and its purpose is to tell the drive to automatically detect whether it should act as the master or the slave device, based on its location on the EIDE ribbon.
- A Drive unit set to Cable Select that appears on the very end of the EIDE cable will act as a Master Drive.
- A Drive unit set to Cable Select that appears on the middle of the EIDE cable will act as the Slave Drive.
Not all motherboards and EIDE ribbons support Cable Select. Check with your motherboard documentation.
Tutorial by Justin Kercher
2005.
This document may not be copied for use on another site.
Copyright© 2005.
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