Buster Mudd wrote:
There was a time when DigiDesign was recommending 10,000 rpm drives,
but they might have lightened up on their requirements. I've been using
7200rpm drives exclusively for the past seven years without a problem.

One possible reason for this is that density on the disk surface
has increased a lot since then. If you leave the head in a certain
position and rotate the disk platter once, then it's going to pass
by a certain number of bits during a revolution. The number of
bits will depend on the density of the data on the disk.

The point is, a disk with a higher density can read more information
in a single revolution. So there is less need to have the highest
rotational speed possible, because you can get very high continuous
transfer rates even at the slower 7200 RPM speed.

However, increased densities don't make high rotational speed
totally obsolete: if you want some data that's on the exact
opposite side of the platter from where the head is, you still
have to wait just as long for the platter to make 1/2 rotation
regardless of the density.

Just wondering, is anyone still extolling the superiority of SCSI or
Ultra-SCSI for audio use, or has that arguement been beaten into
submission by the legions of users successfully working w/ FireWire or
ATA drives 24/7?

FireWire was kind of designed as a replacement for SCSI. It's still
not as fast, though: FireWire 800 is 800 megabits per second. This
is pretty fast, but Ultra320 SCSI is 320 megaBYTES per second. 800
megabits works out to only 100 megabytes. So, the fastest SCSI
available is still three times as fast as the fastest FireWire
available. But it's also basically three times as a expensive, and
as long as one device doesn't need to transfer at more than 100
megabytes per second, you can solve any bus bandwidth problems by
just adding more FireWire buses, which is pretty cheap to do.

Plus, if you really want to crazy about bandwidth, you have to
start considering the bandwidth between the controller and the
CPU (and memory). Most SCSI goes through a PCI bus. Which is
great, but traditional 32-bit 33MHz PCI is only 133 MB/s maximum
bandwidth. So, what's the point of hooking up 320 MB/s SCSI
to something that can't even handle that data? If you want to
really take advantage of it, you'll need to do with something
like 64-bit 66MHz PCI, which gives you 500 MB/s bandwidth, but
costs an arm and a leg and often requires a special motherboard.

Contrast that with Serial ATA that's built in to any new
motherboard. It is often going directly through the motherboard
chipset to the processor and/or memory, so PCI bus limitations
don't apply, and it's 150 MB/s bandwidth, and comes for free with
the motherboard, and the disks are widely available and cheap.

The bottom line is, for most needs, FireWire or SATA are roughly
equivalent (with SATA being 50% faster), and SCSI is not that
much better when viewed as part of the system, unless you go
to great lengths to make sure you get everything just right
(either a motherboard with built-in SCSI or a 64-bit PCI bus).
Or unless you get a newer system with PCI Express, which is
not really mainstream yet, but should be in a year or two.

The other way of looking at it is that pretty much every bus
(SATA, FireWire, regular ATA, SCSI) has the bandwidth for
the maximum sustained transfer speed of one disk. So, if you
never put more than one disk on a single bus, you are probably
fine in most cases.

- Logan