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Using external hard drives for capturing DV video

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January 22, 2004 11:49:13 PM

What is the performance of an external (Firewire or USB 2.0) hard drive compared to a 5400 rpm laptop hard drive? I was going to build a new computer for editing video. After I realized how small my apartment is, I have decided to buy a laptop instead. I'm not sure if the laptop's 5400 rpm hard drive will be fast enough and it definitely won't be big enough. How will a 160 GB, 7200 rpm external Seagate perform in comparison to the laptop hard drive?
January 23, 2004 6:38:09 AM

MUCH better. Firewire or USB2.0 is not a bottleneck. The drive itself is. In essence there is no difference between an external firewire/usb2 drive and an internal of the same type.

<i><b>Engineering is the fine art of making what you want from things you can get</b></i>
January 23, 2004 8:19:03 PM

The figure's don't agree with your statement. The stats for an external 250GB Diamond Max Plus 9 on firewire, read 35MB/s, write 25MB/s. Same drive internal IDE interface, read 47.3MB/s, write 47.3MB/s. (All figures are average.)

Now I don't know what his internal 5,400rpm laptop drive is, but I'd guess it'll read at about 25MB/s and write perhaps 15MB/s.

<A HREF="http://www.anandtech.com/myanandtech.html?member=114979" target="_new">My PCs</A> :cool:
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January 25, 2004 6:56:52 AM

sjonnie or others , do you have read/write speed comparisons for USB as well please , i have only one IDE plug on my board (with 2 HDD's , and i want to run a backup drive , what else can i run a drive off thats quick ?

i have heard of PCI cards for RAID , but isnt a PCI card only good for 33 Mhz bus speed ?

ALSO , what is the best way to isolate a HDD for security , i was looking for a switch on my backup drive to prevent people hacking my system ,and also to keep it free of viruses and trojans.

Is there a hardware 80 pin cable switch available, or can i just put a switch on the power cable to the drive , will that protect it , without causing boot /operting problems , i want it to be a "hot switchable" , is this possible ?
January 25, 2004 12:31:45 PM

Buy a PCI RAID card, you will not experience a bottleneck with a PCI cards. The PCI bus can provide 1Gb/s bandwidth which PATA can provide at miost 133Mb/s (about one tenth of PCI). Also most PCI RAID cards are bootable.

[Insert witty comment here]
January 25, 2004 6:29:27 PM

i have looked for some PCI RAID cards

the ones i have seen seem to only support between 200-266 Mb/sec transfer speeds , not 1000 Mb/sec as you say

I notice that USB 2.0 is supposed to be good for 480 Mb/sec , why dont people run drives off that ?
what is the comparison doing that against RAID 0 , or RAID 0+1
January 25, 2004 8:24:49 PM

That becasue there is no need, the fastest IDE hard drive on the market cant do faster the 100mb/sec and most of then cant do more than 50mb/sec sustained.

[Insert witty comment here]
January 25, 2004 8:42:01 PM

I took the figures from a <A HREF="http://www.tomshardware.com/storage/20031218/index.html" target="_new">Tom's Hardware review </A>. They have USB 2.0 figures there also, hmm
<pre>Firewire Read 34.7MB/s Write 25.2MB/s
USB Read 31.9MB/s Write 26.7MB/s
</pre><p>How swapping of hard disks is possible with hot-swap caddy and an appropriate controller and is a good way of securing your hard disk.

The USB 2.0 spec is 480 Mega bits (Mb)/s or 60 Mega bytes (MB)/s


<A HREF="http://www.anandtech.com/myanandtech.html?member=114979" target="_new">My PCs</A> :cool:
January 25, 2004 9:32:59 PM

OK, I see you're totally confused.

PCI slot is 33MHz x 32-bits, 133MB/s
B=Byte
b=bit

1000Mb/s is about equal to 133MB/s (notice the Megabits and MegaBytes).

PCI is 133MB/s, USB 2.0 is peak 480Mb/s, divide by 8 to get MegaByts/s, and see that USB 2.0 is 60MB/s PEAK.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
January 25, 2004 9:35:13 PM

WRONG, the guy was already confused, he didn't need your mistakes to confuse him more. Fastest drives do around 100MB/s, not 100mb/s. And most newish high performance drives transfer around 50MB/s sustained, not 50mb/s.

If your drive is only 100 megabit, I have a NETWORK that's faster!

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
January 26, 2004 12:12:19 AM

okay , thankyou people , consider me "un-confused"

i understand it now , and see that for example a Promise PCI Raid card is a ;
"32-bit, 66MHz PCI interface that supports data transfers up to 266MB/sec"

However i see average Disc read data transfer rates are only around 49-72 MB/S per disc on Storagereview under Low level Suite 1 for the drives i have listed there)
while looking at the Ziff davis Benchmark , it shows transfer rate as high as 189 MB/s

http://www.storagereview.com/php/benchmark/compare_rtg_...

i guess it depends on so many variables , they can only be assessed after consuming such a high dose of Aspirins that it would prove fatal as my head exploded.
Ouch ,Oh [-peep-] that hurt , did i just confuse myself again ?..lol

I am now reading/educating myself about RAID 0 / RAID 0+1 etc to work out the best redundant storage and backup methods
January 26, 2004 2:49:08 AM

The problem is, 66MHz slots don't exist on PC boards, just server and workstation boards. The card might be compatable with 33MHz slots, but that kind of defeats the purpose, you might as well get a cheaper 33MHz PCI card to begin with.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
January 27, 2004 10:43:12 AM

Sorry, i was typing in a hurry. I do know the difference between bits per sec and bytes per sec.

[Insert witty comment here]
January 27, 2004 3:04:30 PM

I figured it was just something that slipped past you, but given the nature of his confusion it was a bad time for it. Not to insult you or anything.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
!