Disk Technologies ATA, SATA & SAS

Can some one point me to a good resource that point out the
differences amonng the disk technologies?

(or)

good brief resources for each of these (ATA,SATA,SAS)

Thanks a lot,
S

Shivakanth Mundru wrote:
Can some one point me to a good resource that point out the
differences amonng the disk technologies?

(or)

ATA is basically the same spec that has been used for PC disk drives since
the 80s when it started out as IDE. Over that time its gone through a number
of evolutions to improve performance and support bigger drives. The ATA
interface is a parralel I/F, i.e. you have a wide ribbon cable with 40 wires
with data & commands transmitted as a set of synchronized bits over the
wires in the I/F.

SATA is a further evolution of the ATA spec and changes the interface from
the clunky old ribbon cable with 40 wires in parralel to a serial interface
where a 32 bit word would be transmitted as a sequence of bits down a single
connector. There are lots of reasons for changing from the old parralel I/F
to a serial I/F including:

1. Higher speeds, a serial interface can run at much higher bitrates than a
parralel interface (for a given price)
2. Smaller cables make the problem of cable routing much easier in modern
cases
3. Smaller cables don't obstruct airflow which improves cooling and/or
reduces noise (smaller fans etc.)

SAS roughly the same relation to SCSI as SATA has to ATA, i.e. its a serial
interface replacement for the current SCSI standard which is parralel, the
reasons for doing it are roughly the same.


--
Nik Simpson