PATA vs SATA: SCSI(P) vs SAS

[skhan]

Hi,

General impression is Parallel is faster than Serial, but in disk technology it is other way. can any body pls explain brief
or any good/simple document on this

Thanks & Regds
Khan

[IBaltay]

Hi,
this doc on all disk types could help you:
http://h71028.www7.hp.com/ERC/downloads/5982-7353EN.pdf

[Uwe Zessin]

> but in disk technology it is other way.

Not only in disk drive interconnects...

PCI-Express, for example, uses serial technology, too.

On high-speed parallel busses, you must make sure that the signal on all lanes arrives at the same time at the receiver. Take a look at the inner parts of a Cray I computer:
http://en.wikipedia.org/wiki/Image:Cray-1-p1010227.jpg
all the wires have length of 30cm, 60cm and 90cm to compensate for delays in other paths.

And multiple signals can interfere with each other.