ABSTRACT
Input/output (I/O) processing is notoriously slow compared to CPU processing. For example, memory (RAM) access time is measured in nanoseconds, compared to milliseconds for typical (non-SSD) hard disks, a million times slower. A simple read or write operation from an Excel file in MATLAB can take many seconds.*
These examples illustrate the reason why in many applications I/O is the performancelimiting factor. In such application, there is usually no use spending time to tune the data processing (CPU-intensive) or data (memory-intensive), since the I/O tends to be the dominating factor. Owing to I/O’s relative slowness, even simple improvements can have a dramatic effect on the overall program performance.
