A Journey of A Byte:What happens when the program statement: write(textfile, ch, 1) is executed (Cont’d) ?

Part that takes place outside of memory:

• I/O Processor: Wait for an external data path to become available (CPU is faster than data-paths ==> Delays)

• Disk Controller:

  • I/O Processor asks the disk controller if the disk drive is available for writing
  • Disk Controller instructs the disk drive to move its read/write head to the right track and sector.
  • Disk spins to right location and byte is written

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