These pages provide basic information about how hard disk drives work.
How It Works
MOLEX POWER CONNECTOR
The molex power connector on all hard drives provides a four pin power connection to the hard drive. Molex connectors have been around since the evolution of the 8088 computer and will continue to be the primary power type for Ultra ATA hard disk drives and optical storage mediums. There is no sense of the molex power cocnnector being phased out by a popular power connection type. This is because some standards will not change no matter how current standads and technologies change.
On a typical power supply unit (PSU), you'll find multiple Molex connectors, while the same unit has been equipped with only 2 SATA- the most current trend for power connections on hard drives) connectors.
A molex connector consists of one red +5V wire , one +12V wire, and two black grounded wires.
MASTER SLAVE JUMPER PIN
These pins on a ATA hard drive are used to control the "chain of command" of IDE devices within the computer. In a system supporting the ATA standard four hard drives can peacefully co-exist, using a master and slave configuration.
Each channel can operate two devices.
This chain of command mode is described by using the following criteria:
What device refers to the master device.
What device refers to the slave mode.
In an Ultra ATA based system, two channels co-exist because they are labelled differently. Respectively, the master device should be recognized on IDE-0, and the secondary device should be labelled respectively IDE-0 and IDE-1. There can exist two devices on channel IDE-0, and two devices on channel IDE-0
Explanation of Mode
When a device is setup to work in master mode, that hard drive has to be the first device in the chain of command. Also, the second drive needs to be configured as the slave device so that the two can co-exist with each other on the same IDE cable.
In Cable Select (CS) mode each device needs to be configured using the CS jumper setting on the particular device. In this mode, it is not neccessary for a two IDE devices to be referred to as Master or Slave devices, since all devices are communicating based on how the IDE cable connects the devices internally through the system. You still have to setup the jumpers on all devices to use CS mode.
Table 1.1 - Explanation of Master, Slave, and Cable Select Data Transfer Options
40 PIN IDE CONNECTOR
This 40 Pin IDE drive connector allows for the transmission of data between the hard drive and other components in the system. IDE is an older style technology but still remains in popular method for connecting IDE based devices to the motherboard's connections. A large number of workstations still implement IDE technologies since it is cost effective and is compatible with the majority of motherboards old-school and new. IDE devices are also referrred to as PATA (Parellel ATA); both terms reference the same style of hard drive technology.