inter/docs/PROJECT.md

## Inter-process communication between two processes

### System overview

| Process     | Description                                                                                       |
| ----------- | ------------------------------------------------------------------------------------------------- |
| `init`      | Forks 4 child processes, reads data from them, and writes that data to the shared memory          |
| `P1-P4`     | Generates random priority number (in the range 0-19) and sends that priority number to the parent |
| `scheduler` | Creates the shared memory segment, reads data written into it, and prints that data               |

![Project system overview](./media/system-overview.png)

### Implementation criteria

**Criteria 1:**

- Init is a parent process, which forks child processes P1-P4 (`fork` syscall)
- P1-P4: Process should generate a random integer between 0-19 (random number generation or simply hardcoded)
- P1-P4 should send the random integer to init through message passing (`pipe` syscall)
- Init should read data sent by P1-P4

**Criteria 2:**

- Scheduler is an independent process: it should create a shared memory segment (`shmget` and related syscalls)
- Scheduler should read data (a list of random numbers) written by init, sort the list in ascending order, and print the list (sorting algorithm of choice)

**Criteria 3:**

- Init should attach to the shared memory created by the scheduler process (`shmat` and related syscalls, any unique key of choice -> `ftok` syscall is a clean way to accomplish this)
- Init should write random numbers from P1-P4 into the shared memory

**Termination:**

- After scheduler prints the data, init should detach from shared memory and scheduler should detach and delete the shared memory segment (`schmdt` and `shmctl` syscalls)