Parallel vs Serial speed (was: IDE, SATA, RAID0, RAID4, and RAID5)

[markw at mohawksoft.com (markw at mohawksoft.com)]

> Date: Tue, 06 Feb 2007 21:46:22 -0500
> From: David Kramer <david at thekramers.net>
> markw at mohawksoft.com wrote:
>
>> In the above examples, we see that the drives perform similarly, but
>> that
>> the SATA interface gives an advantage in transfer speeds, but not the
>> 100mb/s vs 300mb/s advertised difference.
>
> Here's something I don't undertand.  My gut tells me that a parallel
> interface, which sends all the bits at once, should be several times
> faster than a serial interface, which must send one bit at a time.  So
> how is SATA faster than IDE?

Well, obviously, parallel is "faster" than serial, with the caveat that
serial can be faster if it does something that parallel can't.

Reciting from memory, I recall that SATA uses low voltage differential to
communicate. This is MUCH faster and more immune to noise than the simple
TTL logic level IDE communication.

Theoretically, an 8, 16, or 32 bit cable would be faster, but also more
expensive to produce.

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