From: Sean McCoy <osr@...>
>Not obnoxious at all---to the contrary, this is interesting. I'm not a
>qualified tech-head, but to my understanding the latest Ultra ATA drives
>are capable of transfer rates up to 150 MBytes per second or faster over
>the IDE bus, while the Oxford FireWire 400 bridge passes no more than 50
>MBytes per second no matter what drive is mounted in the FW case. The FW
>800 spec doubles that to 100 MBytes/s, so even that is substantially less
>than a fast drive's potential. Somebody please correct me if I'm wrong.
>
>As the pace of disk speed increases has been outpacing our need for speed
>over the past couple of years, we haven't had to worry about it too much,
>and these numbers are plenty high enough to sustain all but the most
>demanding high definition audio streams. But now that we're adding the
>potentially tremendous disk-streaming demands of huge 24 bit sample
>libraries (VSL, anyone?), disk throughput capabilities are again becoming
>an issue.
I'm not a tech-head either, but like you and unlike most people
quoting computer specs on the Internet, I know enough to know that!
Too many people quote specs like they do understand them, and that
leads to a lot of misinformation floating around.
But I always say that - it's a bee in my bonnet.
Anyway, the important question is how many voices you can get through
Firewire 400's bandwidth, and I believe the practical limit is 350 -
400 mono voices. My understanding is that the drive's transfer rate
isn't so important; it's the seek time that makes the difference.
That's why the Western Digital Raptor 10K RPM SATA drives
(approaching $300 for a 72GB drive) are best for maxing out the
number of voices, even though you can't use the throughput.
The other thing I've learned from my investigations into Windows
machines for streaming samples in Kompakt is that if you use an
add-on SATA card rather than one on the motherboard, the hard drive->
system latency increases. That doesn't matter because of the latency,
but it does make a difference to the timing of the system. Likewise,
tweaked-out memory makes a difference because of its timing with the
motherboard; the speed of the memory itself isn't the important spec.
But people seem to be getting good streaming results on G5s with the EXS.
On the Vienna Symphonic Library forum, their resident computer guru
CM recommends using two 160GB drives for their roughly 230GB library.
You can fit it on one 250GB drive, but the drive is going to be too
full, and that will hurt its performance. He also says that drives
with 2MB buffers seem to be more responsive, but that may have been
an anecdotal off-cuff comment.
--
Nick Batzdorf
818/905-9101, cell 590-9101, fax 905-5434
