Thursday, August 19, 2010

Serial vs Parallel

Why Serial is taking over Parallel Communication?
We have seen the wide spread of USB peripherals, using PCIe over conventional PCI and long ethernet cables... All these represent the approach towards Serial Communication...

Define:
Serial: transfer a bit at a time.
Parallel: transfer multi bits at a time as the number of lanes.

Discuss:
Parallel Communication suffer from the following against Serial Communication:
-More Processing: "takes more time"
-Signal Skewing: due to imperfections in cables, may be a bit would be delayed to others.
-Cross Talking: Signals affects other signals due to magnetic fields resulted from high resonance " not reliable for long distances".
-Larger Size, more cost.


Conclusion:
With the increasing clock speed of the processor:
Parallel transferring becomes not immune to noise especially for long distances, has higher SNR, and less BW.
Serial transferring is much faster, immune to noise, longer distance, and I think easier to program.

Parallel Communication would overcome all these vices if the speed of its data transferring is multiple the speed of Serial Communication and reliable.


However:
As the multi-core processors are being exposed and the clock speed is increasingly higher, the need of parallel applications serial advantageous is vital


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