Hello all.. Q about SCSI technote

lazyart

Hello all. I'm planning to sit for Core on 6/26. I was looking over the SCSI technotes and I see something that may be in error:

Wide
SCSI SCSI-2 (devices)16 (bus width)16 bits (bus speed)10 MHz (Through-put)10 MB/s

Wide SCSI as i understand is 16 bits (hence wide) but isn't the bus speed only 5 MHz? 10 MHz is "Fast" isn't it? That would make the Through-put at 10 MB/s.

For those trying to grasp the chart, divide the bus width by 8, then multiply that value by the bus speed.. this will give you through-put in MB/s.

Normal bus speed (MHz) = 5, Fast = 10, Ultra = 20.
Normal bus width (bits) = 8, Wide = 16.
SCSI-3 is always Wide.

Bus width is also the number of devices allowed on SCSI chain.

Am I correct?

Webmaster

Wide SCSI as i understand is 16 bits (hence wide) but isn't the bus speed only 5 MHz?

I've researched dosens of resources to double-check it, (as I did when I wrote it), but you are correct. The bus speed is only 5 MHz, and the Fast SCSI is 10 (as I said correctly in the foot note of the table) I think I mixed up values from the Fast SCSI-2 and Wide SCSI-2 row...



I apologize for the error, and any confusion it may have caused.

lazyart

With SCSI being one of my weaker points (cable lengths and processor specs--data bus, address limits etc. being the other) I'm kinda proud of myself for spotting it.

This is a wonderful site, BTW. I'm using Syngress/Osbourne texts along with countless notes, tests, and reference material I've gleaned from the web and Kazaa to complete the exams before the amendments kick in later this year. Clean site, and very organized. Thanks for the info here!