First off, the rating was maximum burst-rate, not sustained. The tech
was wrong, it is Bytes, as in 66 Mega-bytes per second. However, UDMA
drives can not sustain that rate. Calculate the spin rate, surface feet
per minute per track, and bit density per track-inch, and you will find
that rate difficult to sustain, with a 5400rpm 3.5 inch disk (A 5 inch
disk would do it easier, more surface feet per minute). What they do is
cache the entire track and burst it out to the controller, whence the
66MBps rating. BTW, most 7200rpm SCSI-UW drives don't hit 80MBps either.
SCSI gets it as an aggregate from multiple drive transfers on the same
bus. This is where UDMA really doesn't scale.
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of D. Carlos
> Knowlton
> Sent: Friday, July 30, 1999 9:57 PM
> To: [EMAIL PROTECTED]
> Subject: Byte the big 'B'
>
>
> Alright, what's going on guys?!
>
> I called Western Digital technical support to find out what I
> need to do to
> get my U-ATA/66 drives to transfer anything near 66MB/s,
> (Mega"bytes", note
> the capital 'B')like all the literature and advertising and
> even the news
> groups are boasting. They corrected me, and said that it is 66Mb/s
> (Mega"bits", as in 1/8th as fast.)
>
> Was I alone in the thinking that the naming convention of
> "'B' means bytes"
> and "'b' means bits" was universal?
>
> (Okay, maybe I am naive =)
>
> -ck
>
