Operating system - Question and Answers - 2

6. Explain the advantages of a multiprocessor system ?
a. Reduce cost: Multiple processors share same resources.
b. Increased Reliability - If one of processor goes down, still the other processors can continue job although its speed will be hampered but it won't stop. 3. c. Increased Throughput - Throughput means the time taken between the request issued by user to the response seen by the user.

7. What is a thread ?
A thread is a basic unit of CPU utilization. In general, a thread is composed of a thread ID, program counter, register set, and the stack.
Thread is a single sequence stream within a process. Threads have same properties as of the process so they are called as light weight processes. Threads are executed one after another but gives the illusion as if they are executing in parallel.

8. What are the benefits of multithreaded programming ?
There is increased responsiveness to the user.
Resource sharing within the process.
Utilization of multiprocessing architecture.

9. What is First-come, first-served (FCFS) ?
First-come, first served (FCFS) is a scheduling technique. With this method, the process which requests the CPU first, that process gets allocated to the CPU first. The execution of the FCFS policy is easily managed with a FIFO queue. As a process enters the ready queue, its Process Control Block is linked with the tail of the queue. In Operating System, FCFS Scheduling is a CPU Scheduling Algorithm that assigns CPU to the process on First Come First Serve basis.

10. What are the different RAID levels ?
The Following RAID levels:
RAID 0  – Striping
RAID 1  – Mirroring
RAID 5  – Striping with parity
RAID 6  – Striping with double parity
RAID 10 – Combining mirroring and striping
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