re: USB and power: USB only supplies 5V @ 500mA max per device. Fine for keyboards and mice, but nowhere near enough to run a printer or scanner, so forget that issue. Firewire also has dedicated power lines, but there's no practical use for them either. Sony dropped those two lines on their i.Link because they knew that most devices will need to be self-powered in order to be useful. Someone quoted USB max throughput 11Mbps vs Firewire 400Mbps. That should be 12 for USB; you might as well compare rated spec to rated spec even if actual observed throughput is less in both cases. Both USB and Firewire talk to storage devices (discs, etc.) using serially encapsulated SCSI commands. Aside from speed limitations, the USB design is inferior to Firewire because it is all master-slave oriented; it requires a host CPU to initiate all transactions on the bus. (Moreover, it is an Intel-originated spec, and everything they produce is designed purely to make you buy more Intel CPUs...) You can only get the full rated USB speed if your CPU is idle enough to poll all the attached USB devices on a consistent schedule. Essentially, your host computer must operate in realtime. In practice, the primary Intel OSes (i.e., Windows!) are completely incapable of realtime operation. Using USB to transfer realtime audio or video on a Windows PC inevitably results in dropouts and glitches. On the other hand, Firewire is a peer-to-peer design, and peripherals don't have to wait for some "master" to poll them before they're allowed to send or receive data. As such, Firewire systems tend to run perfectly glitch-free no matter what any attached PCs are doing. Even with USB 2.0's 480Mbps bus bandwidth, 400Mbps Firewire will still deliver superior performance. re: MD-Data drives vs MD-Audio: MD-Data drives can play audio discs, no problem. They have always been able to do so, whoever told you otherwise was wrong. They just can't read the discs in raw digital form and give you the data as a file. (yet...) re: data transfer rates... 44.1khz 16bit stereo requires 1.44Mbps bandwidth, well within the capability of USB. Yet today's applications seldom get a clean transfer because of USB's dependence on the host CPU which I mentioned above. In a Linux system you may be able to overcome some of the timing problems, but overall it's better to reserve USB for keyboards, mice, and other low-intensity uses and use Firewire when performance and latency really count. Raw capacity of a standard 74-minute MD is about 150MB. It's not the most convenient thing in the world, but you can of course convert your music to ATRAC3 format and store it on MD-Data discs. You need to keep a computer handy for playback... -- Howard Chu Chief Architect, Symas Corp. Director, Highland Sun http://www.symas.com http://highlandsun.com/hyc ----------------------------------------------------------------- To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
