Victor,
Thanks for all of the information.  I greatly appreciate all of the good 
advice.  You covered several points I wondered about. I will keep your words 
of wisdom handy.  What is your opinion of www.newegg.com?  Do you have 
another site that would prove to be better?  I live in the United States.

Thanks for your time and information!
----- Original Message ----- 
From: "Victor Gouveia" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, January 05, 2008 10:31 PM
Subject: Re: [Blind-Computing] external hard drives


> Hi Tammy,
>
> I am also in the market for an external drive, and have found some things
> you should look out for when shopping for these monsters.
>
> First is to look at what kind of interface it has.
>
> USB is the common one, but some models will also come equipped with a
> Firewire cable, and even some will come with an RJ45 jack, which means it
> can be connected to the network and used as a network drive.
>
> Secondly, you'll want to look at the rotation speeds of the disk, 
> sometimes
> measured in RPM's.  The standard is 7200 rpm's.  Anything below that is
> tantamount to very slow access.
>
> Thirdly, and I think this is most important, is the read/write speeds and
> the transfer speeds, usually measured in megabytes per second.
>
> There is really no standard for this, and some retailers will sometimes 
> try
> to fool you into thinking that the higher the transfer speed, the faster
> you'll get data on the drive.  While this can sometimes be true, the fact 
> is
> that the read and write speed is more important than the transfer speed, 
> as
> the transfer will have to wait while the data is being read or written.
>
> The transfer speed may be referring to the transfer rate of the cable or
> connection, and not necessarily the drive itself.  One drive I found was
> boasting a transfer speed of 480 mbps, but the read/write speed was
> abyssmally slow.
>
> An example I can cite is a electronics' chain here in Toronto called 
> Future
> Shop.
>
> They were selling a 500 Gb external hard drive for 99 dollars.  Once I saw
> that, my mouth fell open, as I couldn't believe the price, until I saw the
> read and write speeds, about 27 and 25 mbps, reading and writing,
> respectively.
>
> While this seems high, try to remember that the mbps stands for megabits 
> per
> second, not to be confused with megabytes per second, as most people
> commonly see it as.
>
> What shocked me was the fact that it still said an rpm of 7200, which 
> should
> not support that kind of read write speed, but then I realized what might 
> be
> slowing the read write speeds up, and that leads me into the last point I
> want to make.
>
> Circuitry...
>
> You can have the most expensive hard drive in there, but if the enclosure
> stinks to high heaven, then that really expensive drive means absolutely
> nothing.
>
> The circuitry must come with a cache of some kind, and some kind of power
> switch, as this will control how long the hard drive lasts.  Continuously
> keeping the drive on will shorten the lifespan of the drive.  Although it
> has not been proven to shorten it's lifespan dramatically, it does shorten
> it nonetheless.
>
> So this is what I think you should look out for, and I hope this helps in
> some way.
>
> Victor
>
>
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