forum2342 said:
I am going to add a second hard drive to my current system, which is one disk
(ITA). besides the labor issues, am i better off with a firewire external
drive, or an internal ITA drive?
The main benefit of placing the drive inside the computer,
is performance. The IDE cable can transfer at ATA-100 or
ATA-133. If you use Firewire, that drops to 35MB/sec and
USB might be 30MB/sec or so. (For the last two numbers,
those are from my foggy memory. Firewire can manage a slight
bit more than USB, but the advantage drops when Firewire
drives are chained.)
When the drive is inside your computer, it has cooling and
a large power supply. Enclosures are sometimes a bit weak
on power (the external brick might benefit from a few
more watts of capacity).
This enclosure is a 5.25", meaning it can take an optical
drive. A hard drive is 3.5" across, so doesn't need a
full 5.25" enclosure. But at least with this, you can
be assured it'll take what you plug into it. The back of the
enclosure has two Firewire connectors, and that allows chaining
drives.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817145152
So you can do this with Firewire if you want. I've tried this,
and the second drive transfers at 20MB/sec. The limitation
seems to be a performance issue with the chip inside the
first enclosure, when forwarding packets to the second
drive.
Computer --- 1394a ------+ +----------+ +---
| | | |
+-------+ +-------+
| Drive1| | Drive2|
+-------+ +-------+
With USB, you'd use a hub to get fanout.
Computer --- USB_hub (4 or more ports)
| | .... |
+------+ +------+
|Drive1| |DriveN|
+------+ +------+
Another alternative, is a mobile rack. More than one
new drive can be used, as long as each is mounted in
a removable tray. The rack fits in a 5.25" hole in the
front of your computer. A 3.5" assembly with a handle
on the front, slides out of the computer. The 3.5"
drive fits in that removable assembly. The second item
here, is an additional tray. So you can have two drives
and swap them when needed. This is good for a backup
storage device (versus just additional storage).
KINGWIN KF-21-IPF-B Black Mobile 5.25" HDD Rack
http://www.newegg.com/Product/ProductReview.aspx?Item=N82E16817121109
KINGWIN KF-21-IT 5.25" Black Extra Inner Tray
http://www.newegg.com/Product/ProductReview.aspx?Item=N82E16817121154
(Picture of the product in the first link)
http://kingwin.com/products/KF-Series/kf21ipf8big.jpg
http://kingwin.com/product_pages/kf21ipf.asp
Now, that one is for IDE, and hot swapping is not all
that practical or recommended. You would turn off the
computer, slide the inner tray into place. Lock the
handle. Start the computer and work. That helps ensure
no glitches damage any data.
If you opted for a solution like that, only using
a SATA drive instead, then the tray can be slid out in the
middle of your computing session. SATA supports
hot swap (as long as the proper driver is in place).
You use the "safely remove" icon in the WinXP tray,
and then slide the drive out (as the cache has been
flushed by then).
Either kind of mobile rack, means the drive will be
media limited, rather than cable limited. So you
can transfer files at 70MB/sec, rather than the lower
limits of the external enclosures.
The external enclosures are portable, and as long as
you drag the enclosure, power brick, line cord, USB
cable with you, you could travel to another location
and use it. At one time, you could get external enclosures
where the power supply was built in, and for those,
dragging the enclosure with you is easier.
If you go to a 2.5" drive, the capacity would be smaller,
but the drive can be bus powered via the USB or Firewire
cable. At 2.5 inches, cooling is less of an issue, and
this is where real portable operation becomes more
reasonable. Just the drive and a USB cable.
Regardless of what solution you get, the design should pay
some attention to cooling. Some of the disk drive makers, have
their own product lines consisting of an enclosure without
a fan, plus a pre-installed hard drive. Some of these die
in as little as a couple days. You should read the reviews
on Newegg for some of these storage concepts, to see
exactly how reliable they are.
If doing secondary storage with today's hard drives, you're
advised to get *two* drives and store the data on both of
them. For example, I saw a bare disk drive today for $48,
and that is just too cheap. You know a drive like that will
die when you least expect it. Read the reviews to see what
other people think about them.
Paul
