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REAL TIME PROGRAMMING

• central issue: something has to keep up with the flow of data to/from the audio interface.
• failure leads to audible clicks and/or lost data.

ALTERNATIVES

• kernel (driver) buffers data to/from user space, reads/writes during IRQ handling.
• user space (app) buffers data, does I/O periodically.
• user space (app) reads/writes whenever I/O is possible.

KERNEL BUFFERING

• increases latency
• installs policy in kernel space (bad!)

USER-SPACE BUFFERING

• increases latency
• tricky to get 100% correct

USER-SPACE I/O-on-demand

• requires real-time programming
• less resilient to scheduling-induced audible artifacts.