CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which mechanism maps a device's control registers into the processor's address space so they can be accessed like memory locations?
A. Demand paging
B. Disk mirroring
C. Time sharing
D. Memory-mapped I/O
Correct Answer: D
Memory-mapped I/O lets device registers be read/written using normal memory-address operations.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which term refers to a software-managed queue of pending I/O operations?
A. I/O queue
B. Page table
C. Boot sector
D. Environment variable
Correct Answer: A
Operating systems queue I/O requests until devices/controllers can service them.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
What is device independence in an operating system?
A. All devices must be from one manufacturer
B. Applications use common interfaces without needing to know device-specific hardware details
C. Every device uses identical electronics
D. Drivers are unnecessary
Correct Answer: B
The OS and drivers hide hardware differences behind consistent I/O abstractions.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
What is buffering in I/O?
A. Replacing a file system
B. Stopping all interrupts
C. Using temporary memory to absorb differences in data-transfer rates
D. Encrypting device traffic
Correct Answer: C
Buffers smooth data flow between components operating at different speeds.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which device is most classically associated with spooling?
A. CPU register
B. RAM module
C. Keyboard only
D. Printer
Correct Answer: D
Print spooling queues output on disk/memory so multiple jobs can share a slower printer.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Compared with polling, interrupt-driven I/O often improves CPU efficiency because:
A. The CPU can do other work until the device signals completion
B. It disables device drivers
C. It removes all I/O queues
D. It prevents context switches
Correct Answer: A
Interrupts avoid continuous status checking while slow devices operate.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which I/O technique repeatedly checks a device's status register until it becomes ready?
A. Virtualization
B. Polling
C. Paging
D. Journaling
Correct Answer: B
Polling uses repeated CPU checks instead of waiting for an interrupt.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which software component converts generic operating-system I/O requests into commands understood by a hardware device?
A. Linker
B. Text editor
C. Device driver
D. Compiler
Correct Answer: C
A device driver provides the device-specific control interface used by the OS.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
An interrupt generated by an external hardware device is called a:
A. System call
B. Page table
C. Shell command
D. Hardware interrupt
Correct Answer: D
Hardware interrupts notify the CPU that a device or external event needs service.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which mechanism allows a device controller to transfer blocks directly between a device and main memory with minimal CPU involvement?
A. Direct Memory Access (DMA)
B. Paging
C. Spooling
D. Context switching
Correct Answer: A
DMA reduces CPU overhead for bulk I/O transfers.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which RAID level improves performance by striping data across drives but provides no redundancy by itself?
A. RAID 10 only
B. RAID 0
C. RAID 1
D. RAID 5 only
Correct Answer: B
RAID 0 stripes data for performance/capacity but any drive failure can lose the array's data.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which storage technique keeps identical copies of data on two drives to improve availability?
A. Paging
B. Spooling
C. RAID 1 mirroring
D. RAID 0 striping
Correct Answer: C
RAID 1 mirrors data across drives, providing redundancy if one copy fails.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which term describes attaching a file system to a directory in the existing namespace on Unix-like systems?
A. Paging
B. Compiling
C. Spooling
D. Mounting
Correct Answer: D
Mounting makes the contents of a filesystem accessible at a chosen mount point.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
What is journaling in a file system mainly intended to improve?
A. Crash recovery and filesystem consistency
B. CPU clock speed
C. Screen resolution
D. Password strength
Correct Answer: A
A journal records pending metadata/data changes so recovery after interruption is faster and safer.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which file system is designed for broad compatibility on removable media and supports files larger than FAT32's 4 GiB limit?
A. UFS only
B. exFAT
C. FAT12
D. ext2
Correct Answer: B
exFAT was designed for flash/removable storage and supports large files.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which file system is commonly used on Linux and supports journaling?
A. FAT16 only
B. HFS Classic
C. ext4
D. NTFS only
Correct Answer: C
ext4 is a widely used journaling Linux file system.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which Windows file system supports access-control lists, journaling, compression, and encryption features?
A. FAT12
B. ISO 9660 only
C. ext2
D. NTFS
Correct Answer: D
NTFS is Windows' main feature-rich local file system for many installations.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which partitioning scheme is associated with UEFI systems and supports more partitions and very large disks than traditional MBR?
A. GPT
B. FAT12
C. ASCII
D. PCB
Correct Answer: A
GUID Partition Table (GPT) is the modern partitioning standard commonly paired with UEFI.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
What is the Master Boot Record (MBR) traditionally located in?
A. The Windows Registry
B. The first sector of an MBR-partitioned disk
C. Every user home directory
D. The CPU cache
Correct Answer: B
The MBR occupies the first sector and contains boot code plus a partition table on MBR disks.
CSS - PMS - CCE - PCS - Basic Computing
Operating Systems
Which disk-scheduling algorithm services requests in one direction and then returns rapidly to the beginning without servicing on the return?
A. SSTF
B. FCFS
C. C-SCAN
D. SCAN
Correct Answer: C
C-SCAN provides more uniform waiting times by servicing in a single direction.