PIO (Programmed Input/Output)
Programmed Input/Output (PIO) is a way of moving data between device s in a computer in which all data must pass through the processor . The Advanced Technology Attachment / Integrated Drive Electronics standard specifies three PIO data transfer rates (mode 0 at 3.3 MBps, mode 1 at 5.2 MBps, and mode 2 at 8.3 MBps). The newer Advanced Technology Attachment standard specifies two higher data transfer rates (mode 3 at 11.1 MBps and mode 4 at 16.6 MBps).
A newer alternative to PIO is Direct Memory Access ( DMA ). It's expected that PIO will be dropped from future industry standards, replaced entirely by DMA and Ultra DMA .