subnet calculator and how to solve problem - computer network

There are two kinds to calculate
1. No subnet borrowing
Class A: 255 . 0    .  0   . 0   ==>network id=8bit, host id=24bit range from 0-127
Class B: 255 .255 .  0   . 0  ==>network id=16bit, host id=16bit range from 128-191
Class C: 255 .255 .  0   . 0 ==>network id=24bit, host id=8bit range from 192-223

Question: give ip adress, and asked to find subnet id, network address, broadcast address?

Ex: IP: 10.45.200.197
we can define this ip as in group A because 10 is in range 0-127
subnet id: 255 .  0  .  0  .  0
    &        10   . 45 . 200. 197
----------------------------------
               10 . 0. 0. 0 Network address
to find broadcast address, we set 32-8 = 24bit at last to 1s.
so we get   |0000 1010 | 1111 1111|1111 1111 |1111 1111 | = 10.255.255.255 broadcast address
2. Subnet borrowing  nework id | subnet id | host
ex: 10 . 16. 8 . 15 it's in class A
subnet borrow 10 bit ==>| 8 | 10 | 14 |
subnet id: |1111 1111 | 1111 1111 | 1100 0000 | 0000 0000|
   &         0000 1010 |0001 0000| 0000 1000 | 0000 1111|
----------------------------------------------------------------
                0000 1010|0001 0000| 0000 0000 | 0000 0000| = 10.16.0.0 Network address
to find broadcast address, we set 14 bit at last to 1s of IP
so we get  |0000 1010|0001 0000 |0011 1111|1111 1111| = 10.16.63.255 Broadcast address

1. Computer Network tutorial - Introduction to Operating System and Process management

each round of CPU can give rights to any specific process among all processes in the task manager. but if the times is short or not enough for CPU, All processes cannot be done.
Example: CPU has 2mn to run all process even the real times is 10mn to finish all process. So CPU doesn't care to finish all process but just do step by steps of given time(2mn). In this case, CPU may need to work 5 times in order to finish all processes. It means that cpu work 2mn for 5 times to complete all processes.
How CPU debug:
    CPU need to save the position where it is finished in each 2mn to make sure that it can continue the right position in another 2mn.

content switching

new process ->ready->running->terminate
new process ->ready->running->interrupt->ready->running->terminate
new process ->ready->running->waiting->ready->running->terminate
-copy new process to RAM
-ready to be run but not yet include to Queue
 -Schedule dispatch will choose the Ready process and Change status from Ready to Running
Note( waiting: process at first is ready and send to Running but has some problem before running, so put status into waiting and need to do anything to be ready. In this time, CPU doesn't wait such that process instead of call another Ready status to ->Running status. In this time, if the waiting process is ready, it will be called to run when current process is terminated.

Schedule dispatch: role to choose only 1 process in RAM which considered as the suitable one to send to CPU.
How it choose:
-Lattency
-Round robin ( divide equal time to each process and do it till timeout. This doesn't care whether CPU can finished each process or not. After finishing one round, CPU will come back to do the whole process in the limited time.
-FIFO: ( divide not equal time) CPU cares to finished one process and go to another process.

What is computer Network: is the communication of data between process in the same computer or different computer.

Study OS: the technique of communication of process but not to know clearly about how it communicate.
Study Network: explain the concept of the protocol of communication especially the work of protocol in internet network.
Here it is:
PC platform (source )  --------data pocket------->  Macinfosh platform (destination)
Peer to Peer communication:  is the communication between two layers in the same floor:

There are 7 layers of OSi


Benefits: 
-Reduce complexity
-Standardize interfces
-Facilitates modular engineering
-ensures interperable technology
-Accelerates evolution
-Simplifies teaching and learning