If multiple IDE drives are installed inside a PC, one of the drives must be designated as the master drive. The slave drive will use the integrated controller of the master drive.

One Drive: Set Jumper to Master or Single position.
Two drives: Set jumpers on one drive to Master and the other to slave.

Common Jumper settings. These do not apply to all drives.

Both IDE and the BIOS are individually able to address very large drives. However, together they conspire to limit drive sizes to 528 MB. Some older drives are troublesome in master/slave configurations because they were made before the IDE standard. Never Low Level format an IDE drive as the sector translation information could be destroyed making the drive inoperable.

EIDE's 28-bit sector address can reference a total of 268, 435, 456 sectors allowing hard drives up to 128 GB in size. However the operating system can only use CHS formatted addresses to reference data on the hard drive. Since an enhanced BIOS is limited to 1024 cyl, 256 heads, and 63 sec/track, the real capacity of an EIDE drive is reduced to 8 GB.

CHS (cylinder head sector)

1. The cyl / head / sec values printed on a hard drive's label are for BIOS setup and do not reflect the actual physical values.
2. CHS is limited to:

16 heads
1024 cylinders
504 MB (528 million bytes)

Large (ECHS)

1. Use if drive > 1024 cylinders and bios doesn't support LBA.

LBA (logical block addressing)

1. Linear method of addressing drives space where:

cyl 0, head 0, sec 1 = LBA 0
cyl 0, head 0, sec 2 = LBA 1

regular cable: master at end slave in middle
Cable select cable: notch in line 28.MAster in middle. Slave At end.

All 80 wire ribbon cables are "Cable Select" compatible.
Master at end (black connector). slave in middle (Grey Connector). Blue connector into Mothboard