It depends on the firewire card's chipset stability. I am currently using an Adaptec 4300 card with a Firewire hub and three devices on that plus video monitor out. I had a VIA chipset card and couldn't get more than one device at a time to work. It also depends on the MoBo, XPPro vs Home vs ME,etc. a lot of issues. I had to go through three different firewire cards to find one that would work.

I've never given this issue a lot of thought. My system (900 Mhz/128 mb) came with two firewire ports built in - one in front, one in back. I added the firewire card that came with Pinnacle's Studio DV (the reason I for my original purchase of my present system) - I regularly hook my DV Cam to the built-in rear port, and daisy-chain five external firewire drives hooked into the card. Obviously, whenever I am capturing from the Cam to those external drives, both devices are working simultaneously - and I never experience dropped frames - and, obviously, my machine is quite modest by current standards - one of the reasons I admire SF/Sony for developing such a capable package that doesn't require me to have the biggest and latest machine to get my work finished.

For fun, I recently loaded up Studio 7 (on a second installation of XP Pro - I have a multiboot setup - two installations of XP Pro and 1 installation of ME - I always run experimental or problem programs on that second installation so as to avoid trashing my work environment in the event of a problem).

This second OS is lean of a lot of applications - was playing around with S7's Title Dieko (which I've always admired). Sure enough, just as I had completed some work I wanted to use, S7 crashed on me. I've really never been able to get it running reiliably. OTOH, I can't recall any version of Vegas crashing.

Sorry to wander off topic - sometimes I get carried away.

Anywho, so far, the two 1394 devices I run work just fine.

I'm guessing that I would have the same experience if these were multiple USB devices. Anyone care to comment?

Caruso

It has been said before by folk far more authoritative than I that the video subsystem of Windows only supports one video in or out at one time.

I do know that the regular firewire card implementation that has more than 1 socket on it, is still only exposing a single firewire controller. You can't therefore run upto 400Mb/sec on each connector. You have to put another "NIC" in to even think of heading in that direction. More than 2 firewire cards would near enough saturate a PCI32 33MHz bus (regular PCI) aswell, so it would be attractive to use one of the new consumer mobos that have the motherboard firewire controller on the 266MB/sec southbridge next to the ICH5. Gigabyte have one, more certainly should if you look closely.

Anyway, I know of a realtime video production switcher/NLE system for a PC that uses the MainConcept SDK to access a non-Microsoft-directx-video channel into the firewire OHCI port. Whether you use this system on one firewire card or multiple, it supports multiple video streams inbound concurrently. So what farss asks , strictly speaking, is possible in Windoze, just ~normally not~ and ~probably not~ with Vegas. I guess this could be delivered even by M$ with a directx patch or new version of Windows someday and/or with Vegas.

Firewire is a good protocol, and especially when a video stream is already running, a good firewire storage device should not be able to upset the smooth running but would be expected to operate slower if sharing the same instance of firewire controller. YMMV as all things are not equal.

A bit like with USB/USB2, firewire devices are still a bit young and quirky. The serial, parallel and ethernet port types have all evolved from being slow and troublesome too. Be a little patient with Intel/VIA/M$ whilst you send them your hard earned cash over the years!