of Microprocessors

influences too like interrupts from the network interface or mouse movements or
something that triggers a window redraw. The operating system coordinates all
this to produce an accurate final result but the path and time taken to do so can
vary tremendously.
An analogy to the software system might be a construction site with individual
workers, trucks and other equipment, and outside forces like deliveries and
weather, all working independently. At the same time they are seriously
interdependent for getting materials, sequencing tasks, and so forth. The time to
finish the building is statistical with an average and (typically large) variance.
One way that software synthesis deals with the uncertainty is through the use of
buffers between components. If an upstream component is held up, for example, it
got interrupted for a screen redraw, the buffer following it can still supply data to
the next component downstream. If that buffer should run out, then the next
buffer in the chain keeps the data flowing. If all of the buffers run out, then one
hears a click or program interruption. Larger buffers allow for greater variance in
processing times before defects are heard but at the expense of a greater delay
(latency) through the sequence of steps.
Another way to cut down on variance in a processing step is to utilize only a
fraction of its theoretical power. A synthesis routine for example might have data
structures defined for 100 voices. For all to be active simultaneously, it might
need, say, 70% of available CPU cycles and 80% of available memory access
bandwidth. Almost any event in the system would disrupt this for a time thus
requiring the following buffer to take over and after the disruption, the buffer
would refill slowly. However if only 50 were playing, larger disruptions could be
tolerated and equally important, the buffer would more quickly refill afterward.
The performance of software-based systems can be improved most effectively by
using an operating system specifically designed for audio processing instead of a
general purpose one like Linux or Mac OS or Windows XXX. Since that's not an
option at the moment, elimination of extraneous tasks (you don't really need a
stock ticker running while playing do you?) is probably next most effective
followed by using the fastest processor and largest memory one can afford.
Another issue in the debate regards hardware vs software sound quality.
Software synthesis still must take a lot of computational shortcuts in order to
produce a reasonable number of voices on present PCs and this adversely affects
sound quality. On the other hand, applications like recording or unaltered sample
playback or mixing, which are really just data movement, won't suffer from
computational shortcuts and so can sound excellent. Computers make wonderful
recording systems!
I'm sure everybody has noticed that the number and rate of introduction of
software synthesis products is many times that of hardware. Indeed it seems like