NAHIDUL HASAN

                                            Difference between Preemative and non-Preemative in OS                                                  Github  (Follow me) and Click it for more things Difference Between Preemptive and Non-Preemptive Scheduling in OS It is the responsibility of CPU scheduler to allot a process to CPU whenever the CPU is in the idle state. The CPU scheduler selects a process from ready queue and allocates the process to CPU. The scheduling which takes place when a process switches from running state to ready state or from waiting state to ready state is called  Preemptive Scheduling . On the other hand, the scheduling which takes place when a process terminates or switches from running to waiting for state this kind of CPU scheduling is called  Non-Preemptive Scheduling . The basic difference between preemptive and non-preemptive scheduling lies in their name itself. That is a Preemptive scheduling can be preempted; the processes can be scheduled. In Non-

   Some Useful Command For MongoDB Useful Commands in MongoDB: 1. MongoDB - Create Database use cscorner 2. If you want to check your databases list, use the command show dbs Your created database is not present in list. To display database, you need to insert at least one document into it 3. MongoDB - Drop Database db.dropDatabase() 4. MongoDB - Create Collection db.createCollection(name) db.createCollection("students") 5. MongoDB-Create Document. db.students.insert({"rollno":1,"name":"sunita"}) If the collection doesn't exist in the database, then MongoDB will create this collection and then insert a document into it. 6. MongoDB -Show Collection show collections 7. MongoDB - Drop Collection db.students.drop() 8. MongoDB - Query Document db.students.find() 9. To display the results in a formatted way, you can use pretty method. db.mycol.find().pretty()

 Re-sharing for those who have not checked some or all of the recruitment experiences yet. I have come #Recuriment • 𝐁𝐮𝐬𝐢𝐧𝐞𝐬𝐬 𝐀𝐧𝐚𝐥𝐲𝐬𝐭 1. 𝐵𝑟𝑎𝑖𝑛 𝑆𝑡𝑎𝑡𝑖𝑜𝑛 23 - https://rb.gy/wt53zm • 𝐃𝐚𝐭𝐚 𝐒𝐜𝐢𝐞𝐧𝐭𝐢𝐬𝐭 1. 𝐾𝑜𝑛𝑎 𝑆𝑜𝑓𝑡𝑤𝑎𝑟𝑒 𝐿𝑎𝑏 𝐿𝑖𝑚𝑖𝑡𝑒𝑑 - https://rb.gy/wsxgba • 𝐃𝐚𝐭𝐚𝐛𝐚𝐬𝐞 𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫 1. 𝑇ℎ𝑒𝑟𝑎𝑝 (𝐵𝐷) 𝐿𝑡𝑑. - https://rb.gy/dmjryc • 𝐃𝐞𝐯𝐎𝐩𝐬 1. 𝑇ℎ𝑒𝑟𝑎𝑝 (𝐵𝐷) 𝐿𝑡𝑑. - https://rb.gy/vmpzgk • 𝐆𝐫𝐚𝐝𝐮𝐚𝐭𝐞 𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫 1. 𝐾𝑜𝑛𝑎 𝑆𝑜𝑓𝑡𝑤𝑎𝑟𝑒 𝐿𝑎𝑏 𝐿𝑖𝑚𝑖𝑡𝑒𝑑 - https://rb.gy/v5xckt • 𝐆𝐫𝐚𝐝𝐮𝐚𝐭𝐞 𝐓𝐫𝐚𝐢𝐧𝐞𝐞 1. 𝑅𝑜𝑏𝑖 𝐴𝑥𝑖𝑎𝑡𝑎 𝐿𝑖𝑚𝑖𝑡𝑒𝑑 - https://rb.gy/virj2q • 𝐇𝐑 𝐄𝐱𝐞𝐜𝐮𝐭𝐢𝐯𝐞 1. 𝑇ℎ𝑒𝑟𝑎𝑝 (𝐵𝐷) 𝐿𝑡𝑑. - https://rb.gy/9a2ald • 𝐌𝐚𝐜𝐡𝐢𝐧𝐞 𝐋𝐞𝐚𝐫𝐧𝐢𝐧𝐠 𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫 1. 𝐼𝑛𝑓𝑜𝑙𝑦𝑡𝑥 - https://rb.gy/cpmvba 2. 𝑇ℎ𝑒𝑟𝑎𝑝 (𝐵𝐷) 𝐿𝑡𝑑. - https://rb.gy/1tpapt 3. 𝑇𝑖𝑔𝑒𝑟 𝐼𝑇 𝐵𝑎𝑛𝑔𝑙𝑎𝑑𝑒𝑠ℎ 𝐿𝑡𝑑. - https://rb.gy/olslp2 • 𝐏𝐫𝐨𝐝𝐮𝐜𝐭 𝐀𝐜𝐜𝐞𝐩𝐭𝐚

  CPU Scheduling In the uniprogrammming systems  like MS DOS, when a process waits for any I/O operation to be done, the CPU remains idol. This is an overhead since it wastes the time and causes the problem of starvation. However, In Multiprogramming systems, the CPU doesn't remain idle during the waiting time of the Process and it starts executing other processes. Operating System has to define which process the CPU will be given. In Multiprogramming systems , the Operating system schedules the processes on the CPU to have the maximum utilization of it and this procedure is called  CPU scheduling . The Operating System uses various scheduling algorithm to schedule the processes. This is a task of the short term scheduler to schedule the CPU for the number of processes present in the Job Pool. Whenever the running process requests some IO operation then the short term scheduler saves the current context of the process (also called PCB) and changes its state from running to waiting.