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IDE/ATA Configuration Jumpers

IDE/ATA hard disks are fairly standard in terms of jumpers. There are usually only a few and they don't vary greatly from drive to drive. Here are the jumpers you will normally find:

• Drive Select: Since there can be two drives (master and slave) on the same IDE channel, a jumpers is normally used to tell each drive if it should function as a master or slave on the IDE channel. For a single drive on a channel, most manufacturers instruct that the drive be jumpered as master, while some manufacturers (notably Western Digital) have a separate setting for a single drive as opposed to a master on a channel with a slave. The terms "master" and "slave" are misleading since the drives really have no operational relationship. See this section on IDE/ATA jumpering for more.
• Slave Present: Some drives have an additional jumper that is used to tell a drive configured as master that there is also a slave drive on the ATA channel. This is only required for some older drives that don't support standard master/slave IDE channel signaling.
• Cable Select: Some configurations use a special cable to determine which drive is master and which is slave, and when this system is used a cable select jumper is normally enabled.
• Size Restriction Jumper: Some larger hard disk drives don't work properly in older PCs that don't have a BIOS program modern enough to recognize them. To get around this, some drives have special jumpers that, when set, will cause them to appear as a smaller size than they really are to the BIOS, for compatibility. For example, some 2.5 GB hard disks have a jumper that will cause them to appear as a 2.1 GB hard disk to a system that won't support anything over 2.1 GB. These are also sometimes called capacity limitation jumpers and vary from manufacturer to manufacturer. See here for more on this.

See here for full details on IDE/ATA hard disk setup.

Next: SCSI Configuration Jumpers

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