Many years ago, when I still had my Atari ST with a disk drive only, my friend Martin made one of the wisest observations on computers ever:
I think they should invent a computer that doesn't need to load things.
He was much more spot-on with this than I realised back then. With processing power having mostly become a non-issue since the late 1990s, one of the remaining annoyances about computers is that they make you wait because they have to move data around. They take time to start up, they take their time to launch applications &c. A lot of this will be not due to the complex processing required by these tasks but rather by delays caused by disk access. – The lack of the 'loading' bit is what makes remote controls, switches, little gadgets and large cars so much better to use than computers. You press a button and
bang!, things happen, to use Steve Jobs' word.
[I feel compelled to say here that, sadly, more and more of those simple and instantly working gadgets seem to gain operating systems, delays and the ability to crash lately, decreasing there usability quite a bit. But this is not what I wanted to write about, damnit.]
My point is that my Powerbook's hard drive is plainly slow. In particular, it seems to max out around the data rate that's needed to saturate an Ethernet connection. So with lots of fast networks around me, this means someone copying large files from or to my drive will render the computer almost unusable. This is not due to lack of processing power but solely because OSX is too daft to get the priorities right. This is a personal computer. It's nice that it can do all kinds of file sharing. But it's not a server version. Shouldn't the priorities of everything be adjusted in a way that the performance the machine delivers for my personal use is never affected by any of the background server magic?
Are there any known ways to de-prioritise the hard drive access of server tasks?
Well, this doesn’t directly help with respect to your current problem, but I found this article to be very interesting — a reminder that cheaper isn’t always better, sometimes it’s just… cheaper. Sigh. For many years Macs shipped with SCSI drives by default.