Firewire increases from 400 to 3200 Mbps. But why?
I am an event videographer who has long used DV and silently given thanks many times to those engineers who replaced 12+ cables between my Betacam deck and my capture system (Y in, Y out, R-Y in, R-Y out, B-Y in, B-Y out, Aud-L in, Aud-L out, Aud-R in, Aud-R out, Genlock, RS-422) with one, small wire. FireWire (as apple calls it) and iLink (as Sony calls it) are the IEEE-1394 specification. (Bonus points for the first person who can identify the black AV IO box pictured here in the comments)
First it was FW400 (400 Mbps) and then FW800. But many years have passed since FW800 shipped and the normal rate of development that had us expecting FW1600, etc, left us grossly disappointed for years.
Well, now the 1394 Trade Association has ratified a FW3200 speed.
But will anyone care? …
First the problem was that Apple (the inventor of the FireWire technology that was ratified as the IEEE-1394 specification) was reportedly charging $1 per port. This hindered immediate and widespread adoption on budget computers whereas Intel built its USB onto the motherboards by the millions.
Secondly, USB upped its speed to 480 Mbps with USB 2.0. Then it changed the naming scheme so anything could be called USB 2.0 and this necessitated the additional “High Speed” labeling to indicate those devices that were designed for the faster speeds. For most consumers, this was the end of the story.
USB was built in, and it was faster.
There’s no need for FireWire.
But the reality is that FireWire consistently and resoundly performs better than USB 2.0 High Speed because it is designed to go faster. Moreover it is designed to do more- including TCP/IP over Firewire at FireWire speeds.
As time has passed, and FW800 was left to stagnate, other interconnects provided dramatically faster speeds to external drives. A single external SATA device can easily top 60 MBps. There’s one enclosure with SATA, FW800, FW400 and USB2.0 on it. SATA and FW800 were on par with each other, but even in 2006, SATA was pulling away. Here’s one from 2007.
Another complex issue with FireWire is that one controller chip often handles multiple FireWire ports. This means that, instead of 3 ports x FW400 equaling 1200 Mbps of total throughput, it actually is still just 400 Mbps, or less, because now more devices are trying to pass data through the one chip. As BareFeats tests repeatedly prove, the few companies actually building FW800 onto the motherboard still only use one controller, effectively hobbling the entire system if a single FW400 (or slower) device is connected.
Even if a single FW800 cable is connected to the speediest multi-disk system, it still can’t compare to a multi-lane SATA system. Why not? Because 800 Mbps ÷ 8 bits in a byte = 100 MBps – “overhead” ≈ 70 MBps. Here’s an example.
Though LaCie claims up to 82MB/s, we didn’t see that speed when we tested with QuickBench 3.0 using 100MB block transfers. You might get that speed for smaller size file transfers that fit within the cache of the dual drives.
A single multilane SATA cable can easily blow that away:
PM or Port Multiplication enables one SATA 3G port to transfer data to/from all five drives in the enclosure. Though the “empty” write speed (in our tests) peaked at 213MB/s, the fact that we had five drives capable of a combined speed of over 300MB/s, we were still cranking along at that same speed when we “filled” the volume.
What does that mean? It means you can capture and playback uncompressed HD video beyond the typical 167MB/s target speed no matter how much data you have stored on the RAID volume.
Another feature that FireWire lacks is device assignability. By this, I mean you can’t connect multiple DV devices to one computer even though the 25 Mbps data rate ought to mean you could connect 400 ÷ 25 ≈ about 16 cameras. I’ve tested it and as soon as I connect the third device, nothing works reliably. Moreover, each camcorder or deck is trying to negotiate with the other cameras and decks as to who is playing and who is recording. It’s like trying to herd cats.
If you are using TCP/IP over FireWire and have two computers connected and then daisy a hard drive off of this, FireWire has no way to lock the hard drive to computer A and not computer B. A video deck will not work reliably on either computer if both computers are running video software which is trying to communicate with the deck. Both computers will fight for it.
Because Firewire is designed to be used in AV equipment (cable boxes, D-VHS decks, etc), and because it is designed to handle TCP/IP they ought to extend the Transmission Control Protocol to control the transmission of data from a specific device and to a specific device– and deny requests from other devices once a pairing is made and is in use. This would require computer A to “release” control of the deck so that computer B could then acquire it.
Despite all this, Firewire has distinct advantages that SATA does not have:
- Bus power. So 2.5″ drives need one, and only one cable to the host computer for both power and data. This also works for several 2.5″ drives in a row!
- Daisy-chaining capability. So you can connect several drives in a row to your computer. You do not have to set any device numbers, the devices auto-negotiate.
- Multi-device compatibility. While not generally recommended, you can connect your computer to a hard drive to a second hard drive to an optical drive to a DV deck and use all of them without having to lift a single configuration finger.
getting back to the point of the article here…
Why update the FireWire protocol to 3200 Mbps (or ≈ 350 MBps)?
- It would put it within spitting distance of the current 3G SATA hardware. (and about time if you ask me)
- It would leverage the existing auto-negotiation, bus power, and muti-periphrial capability capabilities. All capabilities that SATA lacks.
- It is leaps and bounds above Gigabit Ethernet, even with “jumbo frames” which some have been using to leverage NAS boxes to handle video.
The bigger question really is if anyone in the industry will actually put FW3200 capability into something. Aside from Apple, almost no one makes use of FW800. The reason you may see it on hard drive enclosures is because Apple has significant market share in enough industries to create enough demand for those products. However, by and large, the number of USB-only enclosures is greater than all other interfaces combined.
The other factor weighing in against FW3200 is that the drive companies make SATA drives. You can put a SATA drive in an enclosure offering FW3200, but it is so much easier to just pass on that SATA connection directly to an external cable that connects to an external port on your PC.
Aside from hard drive throughput, there’s little need for the massive throughout of FW3200 for anything else. And hard drive throughput already has a solution that is that fast, or faster.* It’s called SATA and it’s already built into the fast majority of hard drives and computers shipping today.
So will anyone actually bother with FW3200?
I really don’t think so.
The only company that would is Apple and they would be so much better off if they just put a dedicated external SATA port on their machines- including laptops. It’s already here. External drives and enclosures already have it. Add external SATA ports and you’ll make pro users everywhere very, very happy campers.
* more on “faster” next time.