Dario Greggio wrote:
> Lee Jones wrote:
> 
>> SATA I is 1.5 gigabit per second (150 megabyte per second)
>> from drive to controller.
> [...]
> 
> Yeah, Lee: you're right, this is what I read on SATA disks too.
> It's simply that I could not believe they were "this much faster" than 
> ATA, since their price is comparable...
> 
> What if SATA was in bits per second, and ATA in bytes per second??
> Sometimes these "misunderstanding" happen in electronics... !

ATA is 133MB/s. SATA is 150MB/s. SATA-300 is 300MB/s. It's not much 
better than ATA, especially for the older SATA-150 variety. The big 
benefits are the much more manageable cabling, the dedicated pipe to 
each hard drive, better standarization, etc.

These numbers are irrelevant for most situations, since the speed of the 
actual platters tops out at around 40-80MB/s for most current 7200RPM 
drives. The beginning of the disk is faster than the end, since drives 
use a number of density zones and put more data on the outer edge of the 
disk, which is the start of the data on hard drives (this works the 
exact opposite way with CDs and DVDs). This hasn't changed with SATA. 
SATA drives aren't "much faster" than their ATA counterparts. They're 
somewhat faster, but not by that much.

SATA is great for RAID and the like though. With PATA, two drives on one 
channel share the same cable, and thus split the bandwidth. 66MB/s does 
cause a bottleneck with newer drives, and that's assuming ideal 
conditions otherwise. With SATA, each hard drive gets its own cable, so 
they can both operate at maximum speed.

-- 
Hector Martin (hector@marcansoft.com)
Public Key: http://www.marcansoft.com/marcan.asc

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