clarification and Q&A

1. What is the PCB table and what should it have?
  pid, priority, value, start_time, run_time, and cpu_time   at a minium
      as a note, Some of these are used to calculate the turnaround time and are not printed by the reporter.
  The PCB table will be vector of all the processes in the system, so it may be declared something like:  pcb pcb_table[100];

2. What do you mean by: implement the process manager as a set of major variables:
  Time, PcbTable, ReadyState, BlockedState, and RunningState
      Note, there will be THREE BlockedState variables.  One for each blocked: r0, r1, r2.

  Time is the Time in the system.  ie int Time=0;  will work
     A note: with the cstdio time is already declared as something else, so Time is what I used.

  PcbTable would be an array of all the processes in the system.  You can set it a size of 100 (that won't be more then a 100 processes).
    Do not implement this as a vector of vector of integers.  that's a terrible data structure.

  Ready and BlockedState are using QueueArray (ie priority queues), they will likely be of type integer, since you will use the 
  pid (array index of the pcb) to the process, instead of using a pcb.  

  The runningState (or CPU) would POINT (i.e. store pid) to a single pcb in the vector/array and also must kept information about the quantum, etc.  
  When a process leaves the processor, you will need to update the PCB with all the relevent information.

3. Reporter.
   You only need a fork() the scheduler and the the child (the reporter) would call a reporter method and then exit.  The parent process is the sheduler and would continue to the next command.   


4. The T command and turnaround time.
   The T is the last command issued.  The commander should send that command to the scheduler, which figures out the turnaround time, 
   prints it and then exits the scheduler.  The commander will also exit at this point as well.  Don't forget the wait in the commander, 
   for the scheduler to end.
   You call, you can send the turn around info the commander to print.

5. The Q and C command.  while it may seem simple, increment the time.  Don't forget the scheduler needs check the if the quantum has ended.


6. Yes, I really mean you need to format your output to look like the "last state of the system" example.  columns, etc.  
    Because it's easier to read and grade.
   You may find this helpful:
      cout << "PID  Priority Value  Start Time  Total CPU time" << endl;
      cout << setw(2)  << pid << "  "
           << setw(4)  << priority << "  "
           << setw(7)  << value << "  "
           << setw(11) << start_time << "  "
           << setw(8)  << total_time << endl;

7.  Does it read a file?  No, std in and out are all that is needed.  You can redirect input 
  ./cmdr < hw2_input  
 So you don't have to type the entire file.

8. don't print out a screen capture.  how do I get the output?
  you use file redirection.  using question 7,
  ./cmdr < hw_input >ouput_file  

  output_file has all the output.

9. What are the quantums?
priority 0 is q is 1
priority 1 is q is 2
priority 2 is q is 4
priority 3 is q is 8

10. "Resources are allocated to processes based on priorities."
    Hint: Use a seperate QueueArray for each resource type.

10. "The commander process issues one of the following commands to the process manager every two second:"
    This means the commander should processes the input and only send VALID commands to the manager.

11.  How many cpus are there?  1, only 1.