Does 1394 follows the same logic as USB in terms of number of possible
ports?
On the K8V there is only one external 1394 port and one internal
connector with bundled external module on a bracket. Can I improve
the number of these ports?
Firewire can by connected in a chain of devices:
motherboard ------+ +-------+ +-------+ x
| | | | | |
------- ------- -------
|Device| |Device| |Device|
| #1 | | #2 | | #3 |
------- -------- --------
I tested two Firewire drives connected like this, to a single
Firewire port, and the bandwidth to the second device is about
80% of the bandwidth of the first device. The reason for this
is the design of the bridge chip inside the Firewire disk
enclosure. Some chip designs will be better than others.
I think the chip in my enclosure was limited to 33MB/sec
for traffic passing to the next enclosure.
So, this configuration is not perfect, and you should shop around
for the best designed bridge chips when looking for disk drive
enclosures.
The disk drive enclosures I used, have two Firewire
connectors on the back of them. That is how this wiring
is possible. There are also devices with only one
connector that cannot be connected in a chain, so make
sure a disk enclosure has two connectors, if you want
to use this method.
It is also possible to construct arbitrary networks of
devices, using a device like this. I think this three
port device, can take one port, and provide two output
ports. This one is about $40 when purchased without
additional bus powering. Perhaps purchasing a multiport
PCI Firewire card would be cheaper ?
http://www.unibrain.com/1394_products/fire_repeater/firerepeater.htm
There are also Firewire hubs like this one ($61)
http://www.newegg.com/Product/Product.asp?Item=N82E16817111902
This web page mentions that the node limit per bus is 63
nodes.
http://www.synchrotech.com/support/faq-firewire-01.html
Paul
