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UATA 100/133 VERSUS USB 1.1/2.0

By tdborbas ·
Can someone please enlighten me on the transfer speed of hard drives that use these types of protocols. Which one transfers information faster and by how much. Also, how about the pro's and con's of each. Can these technologies compete with the SCSI hard drives.

Thank you for your time,
Mr. Timothy D. Borbas

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by TheChas In reply to UATA 100/133 VERSUS USB 1 ...

From the FAQ section at www.usb.org with some additions:

Here's a quick list of the maximum transfer rates for various connections in megabits (Mb) and megabytes (MB) per second:

serial port: 115kbits/s (.115Mbits/s)

standard parallel port: 115kBYTES/s (.115MBYTES/s)
ECP/EPP parallel port: 3MBYTES/s

Original USB: 12Mbits/s (1.5MBYTES/s)
Hi-Speed USB: 480Mbits/s
IEEE-1394: 100-400Mbits/s (12.5--50MBYTES/s)

IDE: 3.3-16.7MBYTES/s
UltraIDE: 33MBYTES/s
ATA 100 100MBYTES/s
ATA 133 133MBYTES/s

SCSI-2 (Fast SCSI, Fast Narrow SCSI): 10MBYTES/s
Fast Wide SCSI (Wide SCSI): 20MBYTES/s
Ultra SCSI (SCSI-3, Fast-20, Ultra Narrow): 20MBYTES/s
Wide Ultra SCSI (Fast Wide 20): 40MBYTES/s
Ultra2 SCSI: 40MBYTES/s
Wide Ultra2 SCSI: 80MBYTES/s
Ultra3 SCSI: 80MBYTES/s
Wide Ultra3 SCSI: 160MBYTES/s

FC-AL Fiber Channel: 100-400MBYTES/s

The fastest connection commonly found on PCs is UltraIDE, which is used for hard drives and CD-ROMs.

Now, my 2 bits:
In order of transfer speed:
Serial ATA
ATA 133


USB like ALL serial connections transfers data 1 bit at a time. To properly compare data transfer rates, you need to divide the bit transfer rate by the byte width. Making the effective speed of USB 1/8, 1/16, 1/32 of the rated speed.

ALL IDE drives seldom achieve rated transfer rates. This is because the interface is faster than the read rate off of the platter itself.


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