Q1. Which condition is NOT necessary for a deadlock to occur in an operating system?
Why: The 4 Coffman conditions for deadlock are: Mutual Exclusion, Hold and Wait, No Preemption, and Circular Wait. Preemption actually prevents deadlocks!
Q2. In the IPv4 header, which field is used to prevent datagrams from circulating indefinitely in a routing loop?
Why: Every router decrements the TTL field by 1. When TTL drops to 0, the router discards the packet and sends an ICMP Time Exceeded message.
Q3. Belady's Anomaly occurs in which page replacement algorithm?
Why: Belady's Anomaly is the phenomenon where increasing the number of page frames results in an INCREASE in page faults. It occurs in FIFO page replacement.
Q4. What is the size of an IPv6 IP address?
Why: IPv4 addresses are 32 bits long, whereas IPv6 addresses are 128 bits long (represented in hexadecimal notation).
Q5. Which component of the OS transforms a virtual memory address to a physical memory address?
Why: The MMU (Memory Management Unit) is hardware on the CPU chip that translates virtual addresses generated by CPU to physical RAM addresses.
Q6. Which protocol operates at the Transport Layer of the OSI Model to provide reliable, connection-oriented data transfer?
Why: TCP (Transmission Control Protocol) provides reliable, ordered, error-checked data delivery over connection-oriented sessions at Layer 4.
Q7. Thrashing in an operating system occurs when:
Why: Thrashing occurs when the system spends more time swapping pages in and out of memory than executing actual process code, leading to severe CPU performance degradation.
Q8. What is the standard port number used for HTTPS secure web traffic?
Why: Port 80 is HTTP (unencrypted), Port 443 is HTTPS (TLS/SSL encrypted), Port 21 is FTP, and Port 8080 is an alternative HTTP proxy port.
Q9. Which of the following disk scheduling algorithms services I/O requests like an elevator?
Why: The SCAN algorithm is also called the Elevator Algorithm because the disk arm starts at one end of the disk and moves toward the other end, servicing requests along the way.
Q10. Which MAC layer mechanism is used in Wi-Fi (IEEE 802.11) wireless networks for collision management?
Why: Wi-Fi networks use CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) because wireless transceivers cannot detect collisions while transmitting.