What is the primary purpose of virtual memory in operating systems? A) To increase the size of physical memory B) To provide a mechanism for sharing memory between processes C) To allow processes to access more memory than physically available D) To speed up the memory access time Answer: C Which memory management technique involves dividing physical memory into fixed-size blocks and assigning each block to a process as needed? A) Paging B) Segmentation C) Swapping D) Fragmentation Answer: A What is the main disadvantage of using contiguous memory allocation? A) It leads to external fragmentation B) It requires complex hardware support C) It limits the number of processes that can run simultaneously D) It cannot support virtual memory Answer: A Which memory allocation algorithm aims to minimize wasted memory by allocating the smallest block of memory that is large enough to satisfy a request? A) Best Fit B) First Fit C) Worst Fit D) Next Fit Answer: A What is the purpose of a page table in virtual memory management? A) To map virtual addresses to physical addresses B) To store the contents of all pages in main memory C) To manage the allocation of pages to processes D) To control access permissions for memory pages Answer: A Which mechanism is used to handle the situation when there is not enough physical memory to hold all the currently executing processes? A) Thrashing B) Page replacement C) Swapping D) Fragmentation Answer: C What is the role of the TLB (Translation Lookaside Buffer) in memory management? A) To store copies of frequently accessed pages B) To cache page table entries for faster address translation C) To manage the allocation of pages to processes D) To control access permissions for memory pages Answer: B Which memory management technique allows multiple processes to share a single copy of a program in memory? A) Paging B) Segmentation C) Demand Paging D) Shared Memory Answer: D What is a drawback of using demand paging in virtual memory systems? A) It requires a larger page table B) It increases the disk I/O overhead C) It leads to higher memory fragmentation D) It cannot support multi-programming Answer: B Which of the following is NOT a role of the Memory Management Unit (MMU) in memory management? A) Address translation B) Memory protection C) Process scheduling D) Virtual memory management Answer: C Which of the following is a characteristic of Thrashing in memory management? A) Excessive swapping, resulting in high disk I/O and low CPU utilization B) Efficient utilization of memory resources with minimal overhead C) Fast retrieval of data from secondary storage to main memory D) Optimal allocation of memory to processes, minimizing fragmentation Answer: A In a demand-paged virtual memory system, which page replacement algorithm aims to replace the page that will not be referenced for the longest period of time? A) Least Recently Used (LRU) B) First-In-First-Out (FIFO) C) Clock Replacement D) Optimal Page Replacement Answer: D What is the primary purpose of the Working Set Model in memory management? A) To prevent memory leaks in processes B) To predict the future memory needs of processes C) To determine the minimum number of pages required to prevent thrashing D) To measure the amount of memory a process needs to execute efficiently Answer: D Which of the following is NOT a component of a page table entry in virtual memory systems? A) Valid/Invalid Bit B) Dirty Bit C) Page Table Base Register D) Frame Number Answer: C What is the purpose of the Buddy System in memory allocation? A) To manage fragmentation by combining adjacent free memory blocks B) To implement demand paging by swapping entire processes in and out of memory C) To allocate memory resources dynamically based on the size of the process D) To prevent page faults by preloading frequently accessed pages into memory Answer: A Which memory allocation algorithm divides memory into variable-sized partitions and assigns each partition to a process based on its memory requirements? A) Segmentation B) Paging C) Best Fit D) Next Fit Answer: A What is the purpose of memory protection in operating systems? A) To prevent unauthorized access to system resources B) To allocate memory efficiently among multiple processes C) To minimize fragmentation in the memory allocation process D) To improve the performance of disk I/O operations Answer: A Which of the following is NOT a benefit of using Segmentation in memory management? A) It allows sharing of code segments among multiple processes B) It simplifies memory allocation by dividing memory into fixed-size blocks C) It supports dynamic loading and sharing of libraries D) It provides memory protection by assigning different privileges to segments Answer: B In a multi-level page table scheme, what is the purpose of using multiple page tables? A) To reduce the size of the page table and minimize memory overhead B) To improve address translation performance by caching frequently accessed pages C) To support larger virtual address spaces with a hierarchical structure D) To enable memory compaction and defragmentation processes Answer: C What is the main advantage of using the Buddy System over other memory allocation techniques? A) It minimizes fragmentation by allocating memory in fixed-sized blocks B) It allows for efficient memory compaction and defragmentation C) It provides fast access to memory by caching frequently accessed pages D) It simplifies memory allocation and deallocation operations with low overhead Answer: D In a multi-level page table scheme, what is the purpose of using a Translation Lookaside Buffer (TLB)? A) To store copies of frequently accessed pages for faster retrieval B) To reduce the size of the page table and minimize memory overhead C) To support demand paging by swapping pages between main memory and secondary storage D) To provide memory protection by assigning different access permissions to pages Answer: A Which of the following scenarios is most likely to result in External Fragmentation in memory allocation? A) Allocation and deallocation of memory blocks in a contiguous memory allocation scheme B) Allocation of memory pages to processes in a demand-paged virtual memory system C) Sharing of memory segments among multiple processes in a segmentation-based memory management scheme D) Allocation of variable-sized memory partitions to processes in a buddy system allocation strategy Answer: A What is the primary purpose of implementing Swapping in memory management? A) To reduce the overhead of page table maintenance in virtual memory systems B) To provide a mechanism for processes to share memory segments with each other C) To transfer entire processes between main memory and secondary storage to free up memory space D) To improve memory access time by caching frequently accessed pages in a separate buffer Answer: C Which of the following memory allocation algorithms aims to minimize wasted memory by allocating the largest block of memory that is large enough to satisfy a request? A) Best Fit B) First Fit C) Worst Fit D) Next Fit Answer: C In a demand-paged virtual memory system, which page replacement algorithm is known for its simplicity and low overhead but may suffer from the Belady's Anomaly phenomenon? A) Least Recently Used (LRU) B) First-In-First-Out (FIFO) C) Optimal Page Replacement D) Clock Replacement Answer: B What is the primary purpose of memory relocation in operating systems? A) To increase the size of physical memory B) To allow processes to access memory locations independent of their physical addresses C) To speed up memory access time D) To manage memory fragmentation Answer: B Which of the following memory management techniques requires the use of a Memory Management Unit (MMU) to translate logical addresses to physical addresses? A) Contiguous Memory Allocation B) Paging C) Segmentation D) Fragmentation Answer: B In a demand-paged virtual memory system, what role does the Memory Management Unit (MMU) play? A) It manages the allocation of memory pages to processes B) It translates logical addresses generated by the CPU into physical addresses in main memory C) It controls access permissions for memory pages D) It caches frequently accessed pages for faster retrieval Answer: B What is the primary benefit of using relocation registers in memory management? A) They allow processes to access memory locations without translation B) They prevent memory fragmentation by allocating memory in fixed-size blocks C) They facilitate dynamic loading and sharing of libraries in memory D) They enable processes to execute independently of their physical memory locations Answer: D Which memory management technique involves translating logical addresses generated by the CPU into physical addresses using base and limit registers? A) Paging B) Segmentation C) Swapping D) Contiguous Memory Allocation Answer: D What is the purpose of using base and limit registers in memory relocation? A) To manage the allocation of memory pages to processes B) To prevent memory fragmentation by allocating memory in fixed-size blocks C) To translate logical addresses into physical addresses and enforce memory protection D) To cache frequently accessed pages for faster retrieval Answer: C Which of the following scenarios is most likely to result in memory fragmentation? A) Allocation and deallocation of memory blocks in a contiguous memory allocation scheme B) Allocation of memory pages to processes in a demand-paged virtual memory system C) Sharing of memory segments among multiple processes in a segmentation-based memory management scheme D) Allocation of variable-sized memory partitions to processes in a buddy system allocation strategy Answer: A What is the primary purpose of dynamic relocation in memory management? A) To increase the size of physical memory B) To allow processes to access memory locations independent of their physical addresses C) To speed up memory access time D) To manage memory fragmentation Answer: B Which of the following memory management techniques requires dynamic relocation to adjust memory addresses at execution time? A) Paging B) Segmentation C) Contiguous Memory Allocation D) Fragmentation Answer: B In dynamic relocation, what is the primary benefit of adjusting memory addresses at execution time? A) It reduces the overhead of address translation B) It minimizes memory fragmentation by optimizing memory allocation C) It allows processes to execute in a more secure environment D) It enables processes to be loaded into any available memory location without modification Answer: D What is the primary purpose of dynamic loading in operating systems? A) To compile source code into machine code B) To load executable code into memory only when it is needed C) To link external libraries at compile time D) To allocate memory for processes during system startup Answer: B Which of the following best describes dynamic linking in operating systems? A) Linking external libraries at compile time B) Loading libraries into memory at program startup C) Linking libraries into a program at runtime D) Allocating memory for dynamic data structures Answer: C What is the primary benefit of dynamic loading and linking compared to static linking? A) Reduced memory usage B) Faster program execution C) Greater flexibility and efficiency in resource utilization D) Improved program portability Answer: C Which of the following is an advantage of static linking over dynamic linking? A) Smaller executable size B) Reduced memory overhead C) Improved runtime performance D) Easier maintenance and updating of libraries Answer: A What is the primary disadvantage of static linking compared to dynamic linking? A) Increased memory usage B) Slower program startup time C) Dependency on external libraries D) Limited flexibility in resource allocation Answer: A In dynamic loading, what role does the operating system play in managing memory? A) It allocates memory for processes at system startup B) It loads executable code into memory when requested by the program C) It translates logical addresses into physical addresses D) It manages memory pages to optimize system performance Answer: B Which of the following statements about dynamic loading and linking is true? A) Dynamic loading and linking can only be performed at program compile time. B) Dynamic loading and linking improve program performance but increase memory usage. C) Dynamic loading and linking allow programs to be more modular and flexible. D) Dynamic loading and linking can only be used in conjunction with static linking. Answer: C Which of the following best describes the purpose of free space management in memory management? A) To allocate memory resources among multiple processes B) To manage the placement of processes in memory to minimize fragmentation C) To keep track of available memory blocks for allocation to processes D) To translate logical addresses into physical addresses Answer: C What data structure is commonly used in free space management to keep track of available memory blocks? A) Linked list B) Hash table C) Binary tree D) Stack Answer: A In free space management, what is internal fragmentation? A) Unused memory between allocated blocks B) Unused memory at the beginning of a memory block C) Unused memory within an allocated memory block D) Unused memory at the end of a memory block Answer: C Which memory allocation algorithm selects the first available memory block that is large enough to accommodate the requested size? A) First Fit B) Next Fit C) Best Fit D) Worst Fit Answer: A What is the primary drawback of the first fit memory allocation algorithm? A) It leads to excessive external fragmentation B) It requires sorting the free memory list after each allocation C) It may result in leaving small unusable gaps between allocated blocks D) It has higher computational overhead compared to other algorithms Answer: C What is the primary goal of free space management algorithms in memory management? A) To minimize the time required for memory allocation and deallocation B) To maximize the overall memory utilization and minimize fragmentation C) To prevent processes from accessing unauthorized memory locations D) To allocate memory blocks in a contiguous manner for faster access Answer: B Which memory allocation algorithm selects the memory block that leaves the smallest remainder after allocation? A) First Fit B) Next Fit C) Best Fit D) Worst Fit Answer: C In free space management, what is external fragmentation? A) Unused memory between allocated blocks B) Unused memory at the beginning of a memory block C) Unused memory within an allocated memory block D) Unused memory at the end of a memory block Answer: A What type of fragmentation occurs when there are enough total memory spaces to satisfy a request, but the memory is not contiguous? A) Internal fragmentation B) External fragmentation C) Static fragmentation D) Dynamic fragmentation Answer: B What is the primary function of a page table in memory management? A) To store physical addresses corresponding to logical addresses B) To manage the allocation of memory pages to processes C) To prevent unauthorized access to memory locations D) To facilitate dynamic loading and linking of libraries Answer: A Which of the following statements about paging is true? A) Paging eliminates external fragmentation entirely. B) Paging requires all processes to be of the same size. C) Paging can lead to internal fragmentation. D) Paging relies on dynamic relocation for memory allocation. Answer: C In a paged memory management system, what is the purpose of a page table entry? A) To store the logical address of the page B) To store the physical address of the page frame C) To store the size of the page D) To store access permissions for the page Answer: B What is the primary advantage of paging over contiguous memory allocation? A) Reduced internal fragmentation B) Faster memory access time C) Improved memory protection D) Greater flexibility in memory allocation Answer: D Which of the following statements about TLB (Translation Lookaside Buffer) is true? A) TLB contains physical addresses mapped to logical addresses. B) TLB is a part of the main memory. C) TLB is accessed after accessing the page table. D) TLB is used to manage segmentation. Answer: A How does TLB (Translation Lookaside Buffer) improve memory access performance? A) By reducing the size of the page table B) By storing frequently accessed page table entries for faster translation C) By managing memory segments efficiently D) By swapping memory pages between main memory and secondary storage Answer: B In memory management, what is segmentation? A) The process of dividing main memory into fixed-size blocks B) The process of dividing main memory into variable-sized blocks C) The process of translating logical addresses to physical addresses D) The process of managing TLB entries Answer: B In TLB (Translation Lookaside Buffer), what happens if a requested address translation is not found in the TLB cache? A) The CPU retrieves the translation from the page table in main memory. B) The CPU generates a page fault. C) The CPU searches the TLB cache again after a certain delay. D) The CPU retrieves the translation from the TLB cache of another CPU core. Answer: A What triggers a page fault in memory management? a. Accessing a page that is present in memory b. Accessing a page that is not present in memory c. Accessing a page that is locked in memory d. Accessing a page that is marked read-only Answer: b When a page fault occurs, what does the operating system do? a. Terminates the process immediately b. Swaps out the entire process c. Allocates a new page frame for the requested page d. Retrieves the requested page from secondary storage Answer: d Which of the following is NOT a consequence of a high page fault rate? a. Decreased system performance b. Increased disk I/O c. Increased CPU utilization d. Increased memory utilization Answer: c In a multi-level page table, what is the purpose of the outermost page table? a. To map virtual pages to disk addresses b. To reduce the size of the page table c. To manage access permissions for pages d. To map virtual pages to physical pages in memory Answer: d Which of the following is a disadvantage of using a FIFO page replacement algorithm? a. It requires complex bookkeeping b. It suffers from Belady's anomaly c. It always selects the least recently used page d. It requires frequent updates to the page table Answer: b How does a system prevent multiple page faults for the same page? a. By locking the page in memory b. By using a write-through cache policy c. By using a TLB (Translation Lookaside Buffer) d. By marking the page as dirty Answer: a What is the main advantage of using inverted page tables? a. Reduced memory overhead b. Faster page table lookup c. Improved cache coherence d. Better support for virtual memory fragmentation Answer: a Which algorithm guarantees the lowest page fault rate? a. FIFO b. Optimal c. LRU d. LFU Answer: b Which page replacement algorithm suffers from the phenomenon known as "thrashing"? a. FIFO b. LRU c. Optimal d. Working Set Answer: a Which page replacement algorithm considers recency of page accesses? a. FIFO b. Optimal c. LRU d. Clock Answer: c In the Clock page replacement algorithm, what does the hand pointer indicate? a. The next page to be replaced b. The last page accessed c. The current time d. The total number of page faults Answer: a Which algorithm is susceptible to the "aging" problem, where pages with high frequencies remain in memory longer? a. FIFO b. LRU c. Optimal d. LFU Answer: d What is the main advantage of the Clock page replacement algorithm over FIFO? a. Lower implementation complexity b. Guaranteed optimal performance c. Reduced risk of thrashing d. Better utilization of cache memory Answer: a Which algorithm is often used in real-time systems due to its simplicity? a. LRU b. FIFO c. Optimal d. LFU Answer: b Which page replacement algorithm dynamically adjusts the replacement policy based on the recent history of page references? a. Optimal b. Working Set c. LRU d. LFU Answer: b In the Clock page replacement algorithm, how does the hand pointer move? a. Clockwise b. Counter-clockwise c. Based on the page reference bit d. Randomly Answer: a In the Clock page replacement algorithm, what action is taken when a page fault occurs and the reference bit of the current page is set? a. The page is replaced b. The reference bit is cleared c. The hand pointer moves to the next page d. The page is retained in memory Answer: d Which page replacement algorithm is based on the principle of discarding the page that has not been used for the longest period of time? a. FIFO b. Optimal c. LRU d. Clock Answer: c What is the main drawback of the Optimal page replacement algorithm? a. High implementation complexity b. Inability to adapt to changing memory access patterns c. Vulnerability to thrashing d. Dependency on future page reference information Answer: d In the LFU (Least Frequently Used) page replacement algorithm, how is the frequency of page accesses determined? a. By counting the number of page faults b. By using a timer to track page access times c. By maintaining a counter for each page d. By analyzing the page reference history Answer: c Which page replacement algorithm is prone to the "aging" problem, where older pages may be kept in memory longer than desired? a. FIFO b. Optimal c. LRU d. LFU Answer: d What is the primary drawback of the Clock page replacement algorithm? a. It does not consider page access patterns b. It requires frequent updates to page reference bits c. It suffers from Belady's anomaly d. It may retain frequently accessed pages unnecessarily Answer: a What is the primary advantage of the FIFO page replacement algorithm? a. It guarantees the lowest page fault rate b. It is resistant to thrashing c. It has low implementation complexity d. It adapts well to changing memory access patterns Answer: c What is the maximum file size supported by the FAT32 file system? A) 2 GB B) 4 GB C) 16 GB D) 32 GB Answer: B Which of the following is a characteristic of the ext4 file system? A) Supports file sizes up to 4 TB B) Maximum volume size of 16 TB C) Limited to 256 characters for file names D) Does support journaling Answer: D In the Unix file system, what does the command "chmod 755 file.txt" do? A) Grants read, write, and execute permissions to the owner, and read and execute permissions to the group and others B) Grants read and execute permissions to the owner, group, and others C) Grants full permissions to the owner and read-only permissions to the group and others D) Revokes all permissions from the file Answer: A Which file system is commonly used in macOS? A) NTFS B) FAT32 C) APFS D) exFAT Answer: C What is the main purpose of the journaling feature in a file system? A) To compress files for more efficient storage B) To provide a backup of the file system metadata C) To maintain a log of file system changes for recovery in case of a crash or power failure D) To encrypt files for security purposes Answer: C Which of the following is NOT a type of file allocation method used in file systems? A) Contiguous allocation B) Linked allocation C) Indexed allocation D) Partitioned allocation Answer: D Which of the following is a limitation of the FAT file system? A) Limited support for file fragmentation B) Limited number of files per directory C) Does not support long file names D) Does not support file permissions Answer: B In the Unix file system, what does the command "ls -l" display? A) Only file names B) Detailed information about files including permissions, ownership, size, and modification time C) List of all files including hidden files D) Summary of disk usage Answer: B What is the main advantage of using a distributed file system? A) Improved performance due to centralized storage B) Enhanced security through encryption of files C) Increased reliability and fault tolerance D) Simplified file management for users Answer: C Which file system feature helps reduce fragmentation by reserving contiguous blocks of storage space? A) Defragmentation B) Journaling C) Block suballocation D) Preallocation Answer: D What is a drawback of the Copy-on-Write (COW) technique used in some file systems? A) Increased disk space usage B) Slow file access speed C) Limited support for large files D) Incompatibility with journaling Answer: A Which file system supports the concept of Access Control Lists (ACLs) for fine-grained permissions? A) ext4 B) HFS+ C) ZFS D) NTFS Answer: D What is the purpose of the inode in Unix-like file systems? A) Stores file data B) Manages file permissions C) Stores file metadata D) Tracks file access time Answer: C Which of the following is NOT a feature of the Btrfs file system? A) Copy-on-Write B) Snapshot support C) Transparent compression D) Extent-based allocation Answer: D What does the acronym "RAID" stand for in the context of file systems? A) Redundant Array of Independent Disks B) Rapid Access and Intrusion Detection C) Reliable Allocation of In-memory Data D) Read-after-Write Atomic Disk Answer: A Which file system is primarily designed for flash-based storage devices like USB drives and SD cards? A) JFS B) F2FS C) ReiserFS D) XFS Answer: B In the Unix file system, what is the purpose of the "chown" command? A) Change file ownership B) Change file permissions C) Change file location D) Change file content Answer: A What is the purpose of the "sparse file" feature in file systems? A) To allocate storage space only for non-empty blocks B) To compress files to reduce storage requirements C) To encrypt file contents for security D) To allocate extra space for future file growth Answer: A In the context of file systems, what does the term "inode" stand for? A) Index Node B) Internal Node C) Information Node D) Indexed Node Answer: A Which file system feature allows a single file to be accessed by multiple filenames? A) Hard links B) Soft links C) Symbolic links D) Junction points Answer: A What is the purpose of the "mount" command in operating systems? A) To load device drivers B) To initialize disk partitions C) To associate a file system with a directory in the file hierarchy D) To create a virtual memory space Answer: C Which file system supports the concept of "snapshotting" for creating point-in-time copies of the file system? A) XFS B) Btrfs C) UFS D) JFS Answer: B What is the primary advantage of the Log-Structured File System (LFS) over traditional file systems? A) Faster file access speed B) Reduced risk of data corruption C) Improved disk space utilization D) Better support for large files Answer: B What is the purpose of the "truncate" command in Unix-like operating systems? A) To create a new file B) To remove a file C) To shrink or extend the size of a file D) To change file permissions Answer: C Which file system feature allows for data redundancy and fault tolerance through the use of parity information? A) Journaling B) RAID C) ACLs D) Snapshots Answer: B What is the main advantage of using the ZFS file system's Copy-on-Write (COW) mechanism? A) Improved read performance B) Reduced write amplification C) Lower storage overhead D) Enhanced data integrity Answer: D What is the primary purpose of the "inode table" in a Unix-like file system? A) To store metadata about each file in the file system B) To maintain a log of file system changes for recovery C) To map file names to their corresponding disk addresses D) To allocate and manage disk space for file storage Answer: A What is the primary purpose of the "file system superblock" in Unix-like file systems? A) To store metadata about the entire file system, including size and status B) To maintain a list of free disk blocks available for allocation C) To track changes made to files for journaling purposes D) To store the contents of small files directly within the superblock Answer: A Which file system introduced by Microsoft is optimized for storing large amounts of data and streaming media files? A) NTFS B) FAT32 C) exFAT D) ReFS Answer: D Which Linux file system supports snapshotting, compression, and built-in RAID functionality? A) ext2 B) ext4 C) Btrfs D) XFS Answer: C What is the main advantage of the ReiserFS file system over traditional Linux file systems like ext4? A) Improved support for large files B) Better resistance to fragmentation C) Enhanced scalability for large storage arrays D) Higher performance for random I/O operations Answer: D Which Linux file system features built-in checksums for data and metadata to ensure data integrity? A) ext4 B) XFS C) Btrfs D) JFS Answer: C In Linux, which file system is often used for root (/) partitions due to its fast journaling and recovery capabilities? A) ext3 B) XFS C) Btrfs D) ReiserFS Answer: A What is a key advantage of using the HFS+ file system over FAT32 in macOS? A) Better support for large file sizes B) Improved compatibility with Windows systems C) Enhanced reliability for data storage D) Native support for journaling Answer: D What is the primary purpose of the Extended File Allocation Table (exFAT) file system extension? A) Enhanced support for file compression B) Improved compatibility with Windows and large storage devices C) Built-in encryption support for data security D) Advanced data deduplication techniques Answer: B What is a key feature of the Transparent Compression Extension (TCE) for file systems? A) Automatic encryption of compressed files B) Real-time compression of file data to reduce storage space C) Support for on-the-fly decompression of compressed files D) Integration with cloud storage services for compressed file backup Answer: B What does the Log-Structured File System (LSFS) extension offer in terms of storage optimization? A) Automatic defragmentation of disk blocks B) Continuous monitoring and adjustment of storage allocation C) Improved write performance through sequential logging of file changes D) Transparent compression of file data to reduce disk space usage Answer: C What is a primary characteristic of the Distributed File System (DFS) extension for file systems? A) Centralized storage management for improved data integrity B) Transparent replication of files across multiple storage nodes C) Enhanced support for file-level encryption and access control D) Real-time synchronization of file changes across distributed networks Answer: B What type of file is typically associated with the ".exe" extension in Windows? A) Text file B) Executable file C) Image file D) Audio file Answer: B Which file extension indicates a compressed archive commonly used in Unix-based systems? A) .zip B) .tar.gz C) .iso D) .rar Answer: B What type of file is identified by the ".mp3" extension? A) Image file B) Video file C) Audio file D) Document file Answer: C What type of file does the ".pdf" extension represent? A) Image file B) Audio file C) Document file D) Video file Answer: C Which file extension is commonly used for spreadsheet files in Microsoft Excel? A) .xls B) .docx C) .ppt D) .txt Answer: A What type of file is indicated by the ".avi" extension? A) Audio file B) Video file C) Image file D) Archive file Answer: B In Linux, which file extension typically denotes a shell script file? A) .sh B) .exe C) .bat D) .cmd Answer: A What type of file does the ".jpg" extension represent? A) Audio file B) Video file C) Image file D) Document file Answer: C What is true about blocking I/O? A) It allows multiple I/O operations to be processed simultaneously. B) It causes the calling process to wait until the I/O operation is completed. C) It never interrupts the CPU while waiting for I/O. D) It is also known as non-blocking I/O. Answer: B Which of the following is NOT a characteristic of Direct Memory Access (DMA)? A) It reduces CPU overhead during data transfer. B) It requires CPU intervention for each data transfer. C) It allows peripherals to transfer data directly to/from memory without involving the CPU. D) It improves overall system performance by offloading I/O tasks from the CPU. Answer: B Which of the following is a characteristic of asynchronous I/O? A) It blocks the calling process until the I/O operation is completed. B) It requires explicit polling by the calling process to check for completion. C) It is also known as synchronous I/O. D) It guarantees immediate completion of I/O operations. Answer: B What is the purpose of a device driver in an operating system? A) To provide a graphical user interface for managing devices. B) To translate application requests into commands understood by hardware devices. C) To allocate system resources for I/O operations. D) To optimize CPU scheduling for I/O-bound processes. Answer: B In Unix-like operating systems, what is the purpose of the "select" system call? A) To read input from the user. B) To wait for one or more I/O operations to complete. C) To execute a command in the background. D) To create a new process. Answer: B What is the significance of the "seek" operation in file I/O? A) It retrieves the current position within the file. B) It moves the file pointer to a specified position within the file. C) It flushes the contents of the file buffer to disk. D) It closes the file after the I/O operation is completed. Answer: B Which I/O scheduling algorithm aims to minimize the total time spent waiting for I/O requests to be serviced? A) First-Come, First-Served (FCFS) B) Shortest Seek Time First (SSTF) C) Round Robin D) First-In, First-Out (FIFO) Answer: B What is the purpose of a buffer cache in an operating system? A) To store frequently accessed data from secondary storage devices. B) To cache instructions for frequently executed programs. C) To manage memory allocation for device drivers. D) To optimize CPU scheduling for I/O-bound processes. Answer: A Which of the following is NOT a valid I/O device category? A) Block Devices B) Character Devices C) Network Devices D) Sequential Devices Answer: D What is the primary purpose of a device controller in I/O operations? A) To interpret high-level commands from the CPU and execute them on the device. B) To manage the physical connection between the CPU and the device. C) To convert data between different representations used by the CPU and the device. D) To provide a user interface for interacting with the device. Answer: A What is the main advantage of scatter-gather I/O over regular I/O operations? A) It allows data to be transferred between multiple devices simultaneously. B) It reduces the overhead of managing large data transfers by using separate buffers. C) It eliminates the need for device drivers. D) It provides real-time synchronization between the CPU and I/O devices. Answer: B Which technique is used to prevent I/O devices from monopolizing the CPU's attention in a multitasking environment? A) Interrupt-driven I/O B) Polling C) DMA (Direct Memory Access) D) Spinlocks Answer: A In the context of I/O operations, what is the purpose of a semaphore? A) To synchronize access to shared resources among multiple processes. B) To handle exceptions generated during I/O operations. C) To manage the memory allocation for device drivers. D) To provide a user-friendly interface for interacting with I/O devices. Answer: A How does a ring buffer enhance I/O performance in operating systems? A) It reduces the need for device drivers by directly accessing hardware registers. B) It minimizes contention and overhead by allowing continuous, cyclic data storage. C) It eliminates the need for interrupts by continuously polling I/O devices. D) It provides real-time synchronization between multiple I/O devices. Answer: B What distinguishes memory-mapped I/O from I/O-mapped I/O in terms of addressing? A) Memory-mapped I/O uses separate address spaces for memory and I/O devices, while I/O-mapped I/O shares a unified address space. B) Memory-mapped I/O directly maps I/O device registers into the CPU's address space, while I/O-mapped I/O uses special instructions to access devices. C) Memory-mapped I/O requires special hardware support, while I/O-mapped I/O relies solely on software emulation. D) Memory-mapped I/O is exclusive to certain CPU architectures, while I/O-mapped I/O is universally supported. Answer: B Which of the following is a characteristic of vectored interrupt-driven I/O? A) It requires the CPU to poll devices regularly for data transfer. B) It allows multiple devices to share a single interrupt request line. C) It utilizes DMA for direct data transfer between devices and memory. D) It is commonly used in real-time operating systems only. Answer: B In the context of disk scheduling algorithms, which one prioritizes requests based on their proximity to the current disk head position? A) SCAN B) C-LOOK C) LOOK D) SSTF Answer: D What does the term "seek time" refer to in disk I/O operations? A) The time taken to transfer data between the disk and memory. B) The time taken for the disk arm to position itself over the desired track. C) The time taken for the CPU to process a disk I/O request. D) The time taken for the disk to spin up to the required rotational speed. Answer: B What is the primary function of the I/O scheduler in an operating system? A) To manage the allocation of CPU resources to I/O-bound processes. B) To prioritize and schedule pending I/O requests to optimize disk performance. C) To provide a user interface for interacting with input/output devices. D) To control access permissions for input/output operations. Answer: B Which I/O technique allows data transfer between the CPU and I/O device without the need for continuous polling or interrupts? A) Direct Memory Access (DMA) B) Programmed I/O C) Interrupt-Driven I/O D) Memory-Mapped I/O Answer: A Which of the following statements accurately describes spooling? A) It stands for "Simultaneous Peripheral Operations Online." B) It allows multiple I/O operations to be processed simultaneously. C) It involves storing data in a temporary queue to balance processing speed. D) It is primarily used for managing printer output in batch processing systems. Answer: C Which disk scheduling algorithm minimizes the total seek time by serving requests in the order they are received? A) SCAN B) C-SCAN C) FCFS (First-Come, First-Served) D) SSTF (Shortest Seek Time First) Answer: C In the context of I/O operations, what does "pipelining" refer to? A) The process of combining multiple I/O requests into a single data stream. B) The concurrent execution of multiple stages of an I/O operation to improve throughput. C) The routing of data between input and output devices using a network of pipelines. D) The division of I/O tasks into smaller subtasks to be executed in parallel. Answer: B What distinguishes programmed I/O from interrupt-driven I/O? A) Programmed I/O requires the CPU to continuously poll the I/O device, while interrupt-driven I/O allows the CPU to perform other tasks until the I/O operation is complete. B) Programmed I/O uses DMA for data transfer, while interrupt-driven I/O relies on direct CPU intervention. C) Programmed I/O is faster but less efficient than interrupt-driven I/O. D) Programmed I/O is only suitable for low-speed I/O devices, while interrupt-driven I/O is used for high-speed devices. Answer: A Which I/O technique allows multiple I/O operations to be initiated simultaneously and completed independently? A) Scatter-gather I/O B) Asynchronous I/O C) Synchronous I/O D) Buffered I/O Answer: B Which disk scheduling algorithm prioritizes requests close to the current position of the disk head, then moves in the direction of increasing track numbers until reaching the last track, and then reverses direction? A) LOOK B) C-SCAN C) SCAN D) SSTF Answer: C What distinguishes synchronous I/O from asynchronous I/O? A) Synchronous I/O allows the CPU to perform other tasks while waiting for I/O completion, while asynchronous I/O blocks the CPU until the I/O operation is finished. B) Synchronous I/O guarantees immediate completion of I/O operations, while asynchronous I/O requires explicit polling for completion status. C) Synchronous I/O involves direct communication between the CPU and I/O device, while asynchronous I/O relies on interrupts for communication. D) Synchronous I/O transfers data directly between memory and I/O devices, while asynchronous I/O buffers data in memory before transferring. Answer: A Which of the following is a characteristic of buffered I/O? A) It transfers data directly between memory and I/O devices. B) It requires explicit intervention from the CPU for each data transfer operation. C) It uses a buffer to temporarily store data during I/O transfers. D) It is slower compared to direct I/O techniques. Answer: C