Disk Write Finished

If the disk is finished reading or writing, then the disk switches memory #49 to the inactive state. More formally,

if the following are true:
  • value of cell 49 at time t = 1
  • disk bytes read at time t = value of cell 46 at time t

then value of cell 49 at time (t + 1) = 0

Cell #46 indicates the number of values to copy, so if the disk bytes read is equal to the value in cell #46, then the disk is finished.

For example, if the following are true:

  • value of cell 46 at time 108 = 3
  • value of cell 49 at time 108 = 1
  • disk bytes read at time 108 = 3

then value of cell 49 at time (108 + 1) = 0

Thus, the value of cell 49 at time 109 is 0.

Try running the simulator below to see the disk change cell 49 to 0 after it is done writing data.

Time: 0
LW Computer IO Simulator

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