What's the point fo having a Firewire external hard drive?

[OM2]

Can someone tell me what the point of having an external Firewire hard disc is?
Firewire is less common and slower than USB 2.
Is there a good reason?

Thanks.


OM

[JohnnyMalaria]

Can someone tell me what the point of having an external Firewire hard disc is?
Firewire is less common and slower than USB 2.
Is there a good reason?

Thanks.


OM

Firewire is NOT slower than USB 2.0. Have a read of these:

http://www.usb-ware.com/firewire-vs-usb.htm
http://www.digit-life.com/articles/usb20vsfirewire/

With USB, all of the data flow has to be managed by software - i.e., your CPU has to get involved. With Firewire, the interface controller can do most of it, leaving the CPU to do more important things.

And all of my external devices (hard drives, DVD recorders etc) have both Firewire and USB 2.0.

As it happens, though, I use the USB 2.0 option to keep the Firewire free for AV/C units.

Finally, Firewire also comes in a 800Mbps flavour (IEEE-1394b), with external devices available that take advantage of it:

http://www.firewiredirect.com/product/423/
http://www.firewiredirect.com/categories/45/

[OM2]

hmmm... ok... i'm convinced.

but... the only reason why i had the question in the first place.. is becuase when u see an external hard drive that has both usb 2 and firewire, the transfer rates of usb 2 will be quoted higher than firewire.

assuming the cpu usage by usb 2 is not an issue... is firewire still quciker?

or am i reading the speeds wrong?

thanks.

[kschang]

USB2 has a higher theoretical throughput, I think. In actuality I doubt any actual device can go that fast. It's actually up to to the HD to go that fast, and an HD only goes that fast when pulling data out of the cache. So I doubt it matter.

[OM2]

hmm... i'll take ur words for it...
but see the following link:

http://www.westerndigital.com/en/products/products.asp?DriveID=147

u'll see the following text:

FireWire 400
Serial Bus Transfer Rate (1394a) 400 Mbits/s (Max)

USB 2.0
Serial Bus Transfer Rate (USB 2.0) 480 Mbits/s (Max)

y would ALL external hard drive manufacturers quote wrongly?

(only asking becuase i don't know!)

[Speedy2]

Well I just want to add to the confusion.

As you have USB 1.1 and USB 2.0 there is also 1394a and 1394b. Where 1394a is sometimes called firewire 400 and 1394b is firewire 800. I would think 1394b would leave USB 2.0 in its dust.
(800 Mbits)

My motherboard on my desktop that I built 3 years ago has the 1394b connections. Not as widely used but it is available.

Speedy2

[OM2]

ok... makes more sense.
i've never seen an external hard drive with 1394b??

[kschang]

Not very popular yet, 1394b...

Besides, as I said before, an HD would not deliver data that fast any way. So they are not "wrong", they're just, well, quoting the best part. It's like car manufacturers advertising 0 to 60 times when you would NEVER need to do that kind of jackrabbit start.

Do a search on Google and you'll find independent makers making those external HD's. The catch is they don't come with convenience features like push-button cloning and stuff like that.

[jagabo]

hmm... i'll take ur words for it...
but see the following link:

http://www.westerndigital.com/en/products/products.asp?DriveID=147

u'll see the following text:

FireWire 400
Serial Bus Transfer Rate (1394a) 400 Mbits/s (Max)

USB 2.0
Serial Bus Transfer Rate (USB 2.0) 480 Mbits/s (Max)

y would ALL external hard drive manufacturers quote wrongly?

They aren't quoting wrongly. They are quoting the actual speed bits travel down the wires. USB2, being a shared bus protocol, has a lot of protocol overhead. The final sustained output is in the range of 20 to 30 MBytes/sec (160 to 240 Mbits/sec), slower than any 3.5 inch hard drive manufactured today. Firewire's point-to-point protocol allows much more efficient use of its raw bandwidth.

[greymalkin]

so would you rather have the 4,000lb car with 400 hp or the 1,000lb car with 200.

[edDV]

hmm... i'll take ur words for it...
but see the following link:

http://www.westerndigital.com/en/products/products.asp?DriveID=147

u'll see the following text:

FireWire 400
Serial Bus Transfer Rate (1394a) 400 Mbits/s (Max)

USB 2.0
Serial Bus Transfer Rate (USB 2.0) 480 Mbits/s (Max)

y would ALL external hard drive manufacturers quote wrongly?

(only asking becuase i don't know!)

http://en.wikipedia.org/wiki/USB#Speeds

Manufacturers are using the misleading theoretical burst specs that have never been reached in practice for practical sustained transfer. Even a dedicated USB2 point to point connection (480 mode) has difficulty reaching 160-280 Mb/s (20-35 MB/s) sustained and that comes with significant CPU load.

Sometimes mother board USB2 ports top below 24Mb/s with multiple devices connected, many dropping to USB1.1 11Mb/s when USB 1 devices are connected to the same hub.

Sustained performance* on my various external USB2 drives (all WD or Maxtor 7200RPM) ranges from 140-240 Mb/s (18 to 30 MB/s). The same drives connected to the PATA mother board disk controller score 40-59 MB/s.

IEEE-1394 sustained transfer* falls between those scores, somewhat faster than USB2 but with much lower CPU load. I don't have one here at the moment to test.


* I'm using the Canopus "Raptor Test" Utility that qualifies hard drives for sustained reads and writes. These scores differ for inside disk tracks vs outside edge track reads and writes.

[JohnnyMalaria]

ok... makes more sense.
i've never seen an external hard drive with 1394b??

I provided a link to just such a beast...

[Grain]

and then there's eSATA...

[edDV]

and then there's eSATA...

Yes, eSATA should match the internal transfer rates so long as cable lengths are reasonable. eSATA should also have low CPU load since a hardware controller is used.

Next up for RAID speeds, extreme SCSI and then fibrechannel.

[p_l]

As a matter of experience, I've found that firewire drives are more reliable for sustained, uninterrupted transfers of large files, for example video files. I've had USB transfers crap out on me. Therefore, for my 1.63 TB of HD real estate, of the four external drives I have hooked up, only one is USB and the other three are daisychained (another advantage) firewire enclosures.

[MOVIEGEEK]

As a matter of experience, I've found that firewire drives are more reliable for sustained, uninterrupted transfers of large files, for example video files. I've had USB transfers crap out on me. Therefore, for my 1.63 TB of HD real estate, of the four external drives I have hooked up, only one is USB and the other three are daisychained (another advantage) firewire enclosures.

I agree,also USB shares resources so if you have 2 devices running then the throughput will be less...whereas firewire throughput isn't effected by how many devices are connected(up to 63).

[edDV]

I agree as well but downside of IEEE-1394 PC cards is strange behavior if DV capture and hard drive control-transfer is expected off the same IEEE-1394 interface card. Workaround is capture to internal drive. After that step, USB2 works OK.