Oh dear!

I still partition all my drives, not primarily for performance benefits, but (as Max mentions) for easier housekeeping. Formatting your drives as one huge partition is all very well when it's an 80GB model, with with 1TB+ now available I would personally consider it a nightmare ending up with that amount of data in one huge partition.

Moreover, I don’t want all my personal data scattered about with the operating system files, but in an entirely separate partition where it’s easier to backup.

Quote David Topple:

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Nevertheless, if I create, say, three partitions on a drive it's not clear exactly how I define which partition is actually on the outside of the disk and will therefore have the fastest access time. Can anyone help? (By the way, in case it's of any relevance, I'm using Mac OSX Leopard.)

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On Windows (and I suspect with most partitioning utilities) the ‘outermost’ partitions generally get shown on the left hand side of their display. Here's a vintage example (hence the inclusion of Windows 98 as well as Windows XP ) from my PC using PartitionMagic 8, with two drives, where on the upper drive the three Windows partitions are the 'fastest' ones.

The same layout still applies today (in fact I only partitioned a new pair of 650GB drives a couple of weeks ago using PartitionMagic):



However, it's NOT the access time that improves, but the maximum sustained transfer rate (explained in more detail below).

Quote idris y draig:

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it's still jumping around, the files are still spread out, just over a smaller area... probably not all that much difference....

also, if that drive also contains the system drive partition, then you may indeed be making it worse, both for wear and tear, and performance.. as it'll also be caching virtual memory on the drive , on another partition... so having to jump around a lot between partitions.... but on the whole it's not really necessary on todays drives.

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This could well be true on Macs, but in my PC experiments, Windows needs very little file access once your sequencer has finished loading, so having a separate partition for data on the same drive doesn’t impact performance as one might think, simply because your read/write heads don't have to keep darting about between your audio partition and WIndows one. For more details and a graph showing my test results, see the section entitled Windows Activity’ here:

www.soundonsound.com/sos/may05/articles/pcmusician.htm

Quote G-Doubleyou:

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How old is that article?

Current drives have larger caches and faster seek times, make it a nonissue.

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I don’t see that larger caches or faster seek times change the laws of physics Cap’n

The sustained transfer rate will always vary from the outside to the inside of any drive, simply because the read/write tracks are arranged in concentric circles. Since the outer tracks are longer, they contain more sectors, and thus at a fixed spin-speed more sectors of the outer tracks can be read in a single revolution. So the fastest area of any hard drive is always on the outside. With most (but not all) drives, the sustained transfer rate falls steadily from the outside to the inside, and may typically drop by half in the process (I have seen exceptions where the rate suddenly jumps up again slightly in the middle, or falls in multiple steps like a sawtooth waveform, but these seem comparatively rare). This is a typical result, measured using HDtach:



Caches can make a huge difference to performance with regularly-read data because this can be accessed directly from the cache rather than from the drive itself. However, audio files are nearly always at least an order of magnitude greater than the cache size, so in some cases having a large cache size could actually slow audio streaming performance over a smaller one, because the cache contents don’t get used as much.

Now relate this graph to the PartitionMagic display above it to see how the different partitions provide different sustained transfer rates - you can even partition a drive and measure each partition's performance individually to check this if you like

Now the big question is - will you actually see any performance improvement if you split your drive into multiple partitions, and here you do need to be careful. Yes, streaming sample or audio data from an ‘outer’ partition will give you a POTENTIALLY higher MAXIMUM sustained transfer rate, but unless you’re pushing the drive you may not notice any difference in practice


Martin

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YewTreeMagic

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