What is EIDE

What is EIDE?

Answer:

EIDE is the current standard for inexpensive, high performance hard disks. EIDE stands for
Enhanced IDE and that is precisely what it is. Some manufacturers (like Seagate) call it ATA.
You can think of EIDE as a bus - which is a host controller - which controls it, and you can
connect up to four units. Here you see the controller and its two channels:

All Pentium system boards since 1995 have this EIDE controller built into the chip set. That
allows the hard disk and other EIDE units to be connected directly to the system board.

Improvements

The EIDE standard is a great improvement over the old IDE. Here are some examples:
* The Hard disk can exceed the 528 MB IDE limit. Currently the largest EIDE disks are 8.5

GB and this number keeps increasing.
* The hard disk's interface is moved from the ISA bus to the high speed PCI bus.
*Four units can be connected to the system board, which has two EIDE channels. Each
channel can be connected to a master and a slave unit.
The most important feature is the interface directly on the PCI bus. This has given EIDE transfer
speeds and disk capacities, which far exceed older controller principles. Concurrently, there is a
continual development of the protocols, which are needed for the connection between the units
and the EIDE bus.

Four units

The EIDE interface is not designed for hard disks only. There are four channels, which can be
connected to four independent units:
Hard disks (which must be on the primary channel. On some system boards, this has the
greatest transfer capacity)

* CD ROM drives
*DVD drives
*LS-120 drives and other MO drives
* Tape streamers

EIDE is thus designed as an inexpensive all-around interface, which can be connected to all
kinds of storage media.