1.4d Transfer of Data, including Buffers and Interrupts

Buffers


Any Primary Memory (RAM or CPU) is much faster than any Secoundary storage.




Buffer = Small fast memory  to store data already dealt with

Stage 1: Processor -->  ALU --> Buffer  --> Hard Drive
Stage 2: Processor <->  ALU   Buffer  --> Hard Drive
Stage 3(Interrupts):         Processor <->  ALU   Buffer  --> Hard Drive --> CU --
                                                    |                                                                          
                                                 CU <---------------------------------------------------------^


Interrupt - A message from device to processor e.g. I have emptied the buffer now, can I have some more of the data


ALU = Arithmetic Logic Unit