OS FINALS Flashcards
(125 cards)
1
Q
Which of the following best describes the primary storage medium for Hard Disk Drives (HDDs)?
A) Semiconductor chips
B) Magnetically-coated platters
C) Optical discs
D) Flash memory cells
A
Magnetically-coated platters
2
Q
What is the term for the rate at which data flows between a drive and the computer?
A) Seek time
B) Rotational latency
C) Transfer rate
D) Access time
A
Transfer rate
3
Q
Positioning time in an HDD is composed of:
A) Transfer rate and controller overhead
B) Seek time and rotational latency
C) Spindle speed and platter size
D) Block size and sector size
A
Seek time and rotational latency
4
Q
A head crash in an HDD occurs when:
A) The controller fails to process a command
B) The disk head makes contact with the disk surface
C) The transfer rate exceeds the bus capacity
D) The drive receives a power surge
A
The disk head makes contact with the disk surface
5
Q
What is the typical range for seek time in common desktop HDDs?
A) 0.1ms to 0.5ms
B) 1ms to 2ms
C) 3ms to 12ms
D) 15ms to 30ms
A
3ms to 12ms
6
Q
How is average latency calculated for an HDD?
A) Equal to seek time
B) ½ of the time for a full rotation
C) RPM / 60
D) 1/3 of the maximum latency
A
½ of the time for a full rotation
7
Q
What was a characteristic of the IBM Model 350 disk storage system (the first commercial disk)?
A) It used solid-state technology
B) It had a capacity of several Terabytes
C) It used 50 x 24” platters
D) Access time was in microseconds
A
It used 50 x 24” platters
8
Q
Solid-State Disks (SSDs) are a type of:
A) Volatile Memory Drive
B) Magnetic Tape Drive
C) Optical Storage Drive
D) Non-volatile Memory Drive
A
Non-volatile Memory Drive
9
Q
Which of the following is a characteristic challenge of NVM devices like SSDs?
A) They have moving parts, leading to seek time
B) Data must be erased in larger “block” increments before a “page” can be rewritten
C) They are generally less expensive per MB than HDDs
D) They have an unlimited number of erase/write cycles
A
Data must be erased in larger “block” increments before a “page” can be rewritten
10
Q
What does the Flash Translation Layer (FTL) in an NVM controller primarily manage?
A) The speed of data transfer to the PCI bus
B) Tracking which logical blocks are valid and implementing garbage collection
C) The rotational speed of virtual platters
D) Power consumption during idle states
A
Tracking which logical blocks are valid and implementing garbage collection
11
Q
What does “drive writes per day (DWPD)” measure for an NVM device?
A) The average number of read operations per day
B) The expected lifespan in terms of data written daily within the warranty period
C) The speed at which data can be written to the drive
D) The number of physical drives that can be connected per day
A
The expected lifespan in terms of data written daily within the warranty period
12
Q
Why is wear-leveling important for NAND flash memory?
A) To ensure the drive surface is smooth for the read/write heads
B) To distribute write operations evenly across all cells, extending lifespan
C) To reduce the rotational latency of the memory cells
D) To increase the effective transfer rate of the drive
A
To distribute write operations evenly across all cells, extending lifespan
13
Q
DRAM is sometimes used as a mass-storage device (RAM drive). What is its main disadvantage in this role compared to NVM?
A) It is much slower
B) It is volatile
C) It has a higher capacity
D) It has moving parts
A
It is volatile
14
Q
Disk drives are addressed as a large 1-dimensional array of:
A) Cylinders
B) Tracks
C) Logical blocks
D) Physical sectors
A
Logical blocks
15
Q
Low-level formatting of a disk primarily:
A) Installs the operating system
B) Creates partitions for different file systems
C) Divides the disk into sectors that the controller can read and write
D) Sets up user accounts and permissions
A
Divides the disk into sectors that the controller can read and write
16
Q
How are logical blocks typically mapped to the physical sectors of a disk?
A) Randomly to improve access times
B) Sequentially, starting from the innermost cylinder
C) Sequentially, starting from the first sector of the first track on the outermost cylinder
D) Based on the frequency of access for each block
A
Sequentially, starting from the first sector of the first track on the outermost cylinder
17
Q
Which bus interface, connecting directly to the PCI bus, is designed for high-speed NVM devices?
A) SATA
B) USB
C) NVMe
D) eSATA
A
NVMe
18
Q
What is the purpose of a host controller (or host-bus adapter, HBA) in disk attachment?
A) To spin the disk platters
B) To manage the file system structure
C) To act as the interface on the computer end of the bus, sending commands to the device controller
D) To provide non-volatile storage for boot instructions
A
To act as the interface on the computer end of the bus, sending commands to the device controller
19
Q
Which I/O scheduling algorithm services requests in the order they arrive?
A) SCAN
B) SSTF
C) C-SCAN
D) FCFS
A
FCFS
20
Q
Shortest Seek Time First (SSTF) scheduling may lead to:
A) Excessive head movement
B) Starvation of some requests
C) More uniform wait times for all requests
D) Servicing requests only in one direction
A
Starvation of some requests
21
Q
The SCAN disk-scheduling algorithm is sometimes called the:
A) Elevator algorithm
B) FCFS algorithm
C) Round-robin algorithm
D) Priority algorithm
A
Elevator algorithm
22
Q
How does C-SCAN differ from SCAN?
A) C-SCAN services requests in both directions of head movement.
B) C-SCAN only services requests in one direction; on the return trip, it goes to the beginning without servicing.
C) C-SCAN prioritizes requests based on their size.
D) C-SCAN always starts from the middle of the disk.
A
C-SCAN only services requests in one direction; on the return trip, it goes to the beginning without servicing.
23
Q
For NVM scheduling, what is a common approach like NOOP often combined with?
A) Simulating head movement for compatibility
B) Introducing artificial rotational latency
C) Combining adjacent LBA requests
D) Prioritizing write operations over read operations
A
Combining adjacent LBA requests
24
Q
What is write amplification in NVM devices?
A) A technique to increase the speed of write operations
B) The phenomenon where a single logical write causes multiple physical writes/reads due to garbage collection
C) A method to boost the signal strength for data being written
D) Increasing the size of data blocks to improve throughput
A
The phenomenon where a single logical write causes multiple physical writes/reads due to garbage collection
25
A parity bit is a simple form of:
A) Error-correction code
B) Encryption
C) Checksum for error detection
D) Data compression
Checksum for error detection
26
Error-Correction Code (ECC) can:
A) Only detect errors, not correct them
B) Detect and correct some errors
C) Only correct errors, not detect them
D) Prevent all errors from occurring
Detect and correct some errors
27
What is "partitioning" a disk?
A) Dividing the disk into sectors
B) Dividing the disk into one or more groups of cylinders, each treated as a logical disk
C) Formatting the disk with a specific file system
D) Creating a backup of the disk's contents
Dividing the disk into one or more groups of cylinders, each treated as a logical disk
28
The boot block on a disk typically contains:
A) The entire operating system kernel
B) User data files
C) Code to load the operating system from the file system
D) Swap space for virtual memory
Code to load the operating system from the file system
29
Swap space management is used by the OS for:
A) Storing frequently accessed files for faster retrieval
B) Moving processes or pages from DRAM to secondary storage when DRAM is full
C) Backing up critical system files
D) Managing network communication buffers
Moving processes or pages from DRAM to secondary storage when DRAM is full
30
Network-Attached Storage (NAS) provides file access:
A) Through local I/O ports like SATA
B) Over a network, typically presenting as a remote file system
C) Directly to the PCI bus for maximum speed
D) Using raw block devices without a file system
Over a network, typically presenting as a remote file system
31
Cloud storage, unlike NAS, is typically accessed:
A) Only within a local area network
B) Using direct hardware connections
C) Over the Internet via APIs
D) As a raw block device
Over the Internet via APIs
32
What is the primary purpose of RAID (Redundant Array of Inexpensive Disks)?
A) To increase the storage capacity of a single disk
B) To provide data reliability via redundancy and potentially improve performance
C) To reduce the physical size of disk drives
D) To encrypt all data stored on disks
To provide data reliability via redundancy and potentially improve performance
33
RAID Level 0 (striping) offers:
A) High redundancy
B) Improved performance but no redundancy
C) Mirroring of data
D) Parity checking for error correction
Improved performance but no redundancy
34
RAID Level 1 (mirroring) provides:
A) Data striping across multiple disks for speed
B) A duplicate of each disk for redundancy
C) Block interleaved parity
D) Distributed parity for better write performance
A duplicate of each disk for redundancy
35
RAID Levels 4, 5, and 6 use which technique for redundancy?
A) Mirroring
B) Striping without redundancy
C) Block interleaved parity or distributed parity
D) Hot spare disks only
Block interleaved parity or distributed parity
36
What is a "hot-spare" disk in a RAID system?
A) A disk that is actively being used for parity calculations
B) An unallocated disk that automatically replaces a failed disk
C) A disk used for temporary caching of frequently accessed data
D) A disk that is physically hotter due to higher usage
An unallocated disk that automatically replaces a failed disk
37
Solaris ZFS enhances data integrity by:
A) Only using RAID 1 mirroring
B) Using checksums for all data and metadata
C) Compressing all data by default
D) Requiring NVM storage for all pools
Using checksums for all data and metadata
38
Object storage systems typically manage objects within a:
A) Hierarchical directory structure
B) Relational database
C) Storage pool, accessed via object IDs
D) Single large contiguous file
Storage pool, accessed via object IDs
39
The theoretical transfer rate for HDDs (e.g., 6 Gb/sec) is often higher than the effective transfer rate (e.g., 1 Gb/sec) due to:
A) Only controller overhead
B) Factors like bus contention, protocol overhead, and internal drive mechanics
C) Incorrect spindle speed settings
D) The use of NVM caching
Factors like bus contention, protocol overhead, and internal drive mechanics
40
In the context of HDDs, constant angular velocity (CAV) can lead to:
A) A constant number of sectors per track across the entire platter
B) A non-constant number of sectors per track, with outer tracks potentially holding more sectors
C) Faster seek times on inner tracks
D) Reduced rotational latency overall
A non-constant number of sectors per track, with outer tracks potentially holding more sectors
41
What is a "port" in the context of I/O hardware?
A) A software routine for device access
B) A physical connection point for a device
C) A reserved memory area for I/O data
D) A type of I/O scheduling algorithm
A physical connection point for a device
42
A "bus" in a computer system is primarily used for:
A) Executing I/O instructions
B) Storing device driver code
C) Providing a shared communication pathway for multiple devices
D) Cooling I/O controllers
Providing a shared communication pathway for multiple devices
43
What is the role of a device controller (or host adapter)?
A) To provide power to I/O devices
B) To manage the file system on a storage device
C) To provide the electronics that operate a port, bus, or device
D) To store user application data temporarily
To provide the electronics that operate a port, bus, or device
44
Memory-mapped I/O involves:
A) Mapping device control and data registers to locations in the processor's address space
B) Using a dedicated memory chip for all I/O operations
C) Copying all I/O data through main memory multiple times
D) Storing I/O device drivers in a special memory region
Mapping device control and data registers to locations in the processor's address space
45
What is a primary characteristic of "polling" for I/O?
A) The CPU is interrupted by the device when I/O is ready
B) The CPU repeatedly checks the status of the device (busy-wait)
C) Data is transferred directly to memory without CPU intervention
D) It is highly efficient for slow devices
The CPU repeatedly checks the status of the device (busy-wait)
46
An interrupt vector is used to:
A) Store the data being transferred during an interrupt
B) Increase the speed of the I/O bus
C) Dispatch an interrupt to the correct interrupt handler routine
D) Prevent interrupts from occurring
Dispatch an interrupt to the correct interrupt handler routine
47
Direct Memory Access (DMA) is used to:
A) Allow the CPU to directly control I/O device registers
B) Transfer large blocks of data between I/O devices and memory without continuous CPU intervention
C) Speed up the execution of interrupt handlers
D) Map I/O ports into the CPU's memory space
Transfer large blocks of data between I/O devices and memory without continuous CPU intervention
48
What does "cycle stealing" refer to in the context of DMA?
A) The CPU stealing I/O cycles from the DMA controller
B) The DMA controller taking bus cycles from the CPU to transfer data
C) A malicious program stealing CPU time
D) An inefficient I/O scheduling algorithm
The DMA controller taking bus cycles from the CPU to transfer data
49
The device-driver layer in an OS primarily serves to:
A) Provide a user interface for configuring devices
B) Hide the differences among I/O controllers from the kernel, presenting a uniform interface
C) Manage power consumption of I/O devices
D) Schedule I/O requests based on priority
Hide the differences among I/O controllers from the kernel, presenting a uniform interface
50
Which of the following is a characteristic of a "block" I/O device?
A) Data is transferred as a stream of bytes (e.g., keyboard)
B) Data is transferred in fixed-size blocks (e.g., disk drive)
C) It can only be accessed sequentially
D) It does not support random access
Data is transferred in fixed-size blocks (e.g., disk drive)
51
The ioctl() system call in Unix is typically used for:
A) Standard read and write operations on files
B) Direct manipulation of I/O device-specific characteristics
C) Creating and deleting files
D) Mounting and unmounting file systems
Direct manipulation of I/O device-specific characteristics
52
"Blocking I/O" means:
A) The I/O call returns immediately, whether the I/O is complete or not
B) The process is suspended until the I/O operation is completed
C) The I/O operation is performed in the background without process suspension
D) Multiple I/O operations are bundled into a single system call
The process is suspended until the I/O operation is completed
53
"Asynchronous I/O" means:
A) The process is suspended until I/O is completed
B) The I/O call returns immediately, and the process runs while I/O executes, being notified later of completion
C) I/O operations are always performed in the order they are requested
D) The I/O device must be synchronized with the system clock
The I/O call returns immediately, and the process runs while I/O executes, being notified later of completion
54
Vectored I/O (e.g., readv()) allows:
A) Only one I/O operation per system call
B) A single system call to perform multiple I/O operations using a vector of buffers
C) Direct access to device interrupt vectors
D) Faster polling of I/O devices
A single system call to perform multiple I/O operations using a vector of buffers
55
Buffering in the kernel I/O subsystem is used to:
A) Permanently store user data
B) Cope with device speed mismatches and transfer size mismatches
C) Manage user authentication for I/O devices
D) Directly control device hardware registers
Cope with device speed mismatches and transfer size mismatches
56
Caching in the I/O subsystem involves:
A) Storing data in a slow, permanent storage medium
B) Keeping a copy of frequently accessed data in a faster device (like memory) for quicker access
C) Ensuring all data is written to disk immediately
D) Exclusively reserving a device for a single process
Keeping a copy of frequently accessed data in a faster device (like memory) for quicker access
57
Spooling is a technique typically used for devices like printers to:
A) Allow multiple processes to access the device simultaneously and directly
B) Hold output for a device that can only serve one request at a time
C) Increase the raw data transfer speed of the device
D) Provide error correction for data sent to the device
Hold output for a device that can only serve one request at a time
58
I/O protection in an operating system is typically enforced by:
A) Allowing user processes to execute all I/O instructions directly
B) Defining I/O instructions as privileged and requiring I/O to be performed via system calls
C) Encrypting all data transferred to I/O devices
D) Using physical locks on I/O devices
Defining I/O instructions as privileged and requiring I/O to be performed via system calls
59
The Advanced Configuration and Power Interface (ACPI) provides:
A) A standard for network communication protocols
B) Firmware routines for device discovery, management, error handling, and power management
C) A graphical user interface for configuring I/O devices
D) A method for direct memory access by peripherals
Firmware routines for device discovery, management, error handling, and power management
60
A STREAM in Unix System V is:
A) A type of sequential access file
B) A full-duplex communication channel between a user-level process and a device
C) A method for managing disk blocks
D) A hardware component for speeding up network I/O
A full-duplex communication channel between a user-level process and a device
61
Which of the following is a strategy to improve I/O performance?
A) Increasing the number of context switches
B) Reducing data copying between kernel and user space
C) Using small transfer sizes to reduce interrupt overhead
D) Disabling DMA controllers
Reducing data copying between kernel and user space
62
A programmable interval timer (PIT) is used for:
A) Measuring the physical temperature of the CPU
B) Generating periodic interrupts for timing and scheduling purposes
C) Storing the current system time permanently
D) Controlling the speed of the I/O bus
Generating periodic interrupts for timing and scheduling purposes
63
The status register of an I/O device typically holds information like:
A) The data to be written to the device
B) The address of the next I/O command
C) Whether the device is busy, if an error occurred, or if data is available
D) The device driver's version number
Whether the device is busy, if an error occurred, or if data is available
64
Fibre Channel (FC) is often used for:
A) Connecting low-speed peripherals like keyboards
B) High-speed network communication in data centers, often for storage area networks
C) Wireless communication between mobile devices
D) Providing power over Ethernet
High-speed network communication in data centers, often for storage area networks
65
What does an interrupt handler do?
A) It initiates a DMA transfer
B) It polls the device for status updates
C) It's a piece of code that is executed when an interrupt signal is received from a device
D) It manages the system's power states
It's a piece of code that is executed when an interrupt signal is received from a device
66
Which of the following is NOT a typical file attribute stored by the file system?
A) Name
B) Identifier (unique tag)
C) CPU usage of the creating process
D) Protection information
CPU usage of the creating process
67
The open() file operation typically involves:
A) Deleting the file from the disk
B) Searching the directory structure and moving the file's metadata into memory
C) Repositioning the read/write pointer within the file
D) Copying the entire file content into main memory
Searching the directory structure and moving the file's metadata into memory
68
An open-file table maintained by the OS tracks:
A) All files stored on the disk, whether open or not
B) Currently open files, caching their FCBs and other information
C) The history of all file operations performed
D) User login and logout times
Currently open files, caching their FCBs and other information
69
A "shared lock" on a file typically allows:
A) Only one process to access the file for writing
B) Several processes to concurrently acquire the lock for reading
C) No processes to access the file
D) One process to write and multiple processes to read simultaneously
Several processes to concurrently acquire the lock for reading
70
"Mandatory" file locking means:
A) Processes are advised about locks but can choose to ignore them
B) Access to the file is strictly denied or granted based on locks held and requested
C) Locks are only applied to files larger than a certain size
D) Only the file owner can set locks
Access to the file is strictly denied or granted based on locks held and requested
71
In which file access method are records accessed one after another in order?
A) Direct Access
B) Indexed Access
C) Sequential Access
D) Hashed Access
Sequential Access
72
Direct access files are characterized by:
A) Being read only from beginning to end
B) Fixed-length logical records that can be accessed by their relative block number
C) A requirement for an external index to locate any data
D) Variable-length records accessed via pointers
Fixed-length logical records that can be accessed by their relative block number
73
An indexed sequential-access method (ISAM) typically involves:
A) Storing all file data directly in the index
B) A small master index in memory pointing to a larger secondary index on disk, with the file kept sorted
C) Accessing records purely sequentially without any index
D) A single-level directory structure for all files
A small master index in memory pointing to a larger secondary index on disk, with the file kept sorted
74
A "volume" in a file system context is:
A) The physical size of a disk platter
B) An entity (like a partition) containing a file system
C) The sound level produced by the disk drive
D) A type of file compression
An entity (like a partition) containing a file system
75
What is a primary disadvantage of a single-level directory structure?
A) It is too complex to implement
B) It leads to naming conflicts and makes grouping difficult for multiple users
C) Searching for files is very slow
D) It requires excessive disk space for the directory
It leads to naming conflicts and makes grouping difficult for multiple users
76
A tree-structured directory allows:
A) Files to have multiple parent directories directly
B) Users to organize files hierarchically, but does not allow sharing of subdirectories
C) Only a single directory for all users
D) Cycles in the directory graph
Users to organize files hierarchically, but does not allow sharing of subdirectories
77
An acyclic-graph directory structure allows for:
A) Cycles, where a directory can be a descendant of itself
B) Shared subdirectories and files using links
C) Only one name per file
D) A maximum of two levels in the directory hierarchy
Shared subdirectories and files using links
78
What is a "dangling pointer" in the context of acyclic-graph directories?
A) A pointer to a file that has been backed up
B) A link or pointer that points to a no-longer-existing file or directory
C) A file that has no links pointing to it
D) A pointer that uses an excessive amount of memory
A link or pointer that points to a no-longer-existing file or directory
79
File system mounting is the process of:
A) Physically installing a new disk drive
B) Making a file system accessible at a specific location (mount point) in the directory hierarchy
C) Formatting a disk partition with a file system
D) Copying all files from one file system to another
Making a file system accessible at a specific location (mount point) in the directory hierarchy
80
Network File System (NFS) is a common protocol for:
A) Low-level disk formatting
B) Distributed file sharing across a network
C) Managing swap space
D) Encrypting files on a local disk
Distributed file sharing across a network
81
Consistency semantics in file sharing define:
A) The physical layout of files on a disk
B) How multiple users access a shared file simultaneously and when modifications are visible
C) The error checking and correction codes used by the file system
D) The naming conventions for files and directories
How multiple users access a shared file
82
UNIX file system semantics typically ensure that:
A) Writes to an open file are only visible after the file is closed
B) Writes to an open file are visible immediately to other users of the same open file
C) Each user opening a file gets a private copy
D) Files cannot be shared between different users
Writes to an open file are visible immediately to other users of the same open file
83
AFS (Andrew File System) session semantics mean that:
A) Writes are visible immediately to all other sessions
B) Writes to an open file are only visible to new sessions starting after the file is closed
C) All users share the same file pointer
D) Files are locked exclusively during a session
Writes to an open file are only visible to new sessions starting after the file is closed
84
Which of the following is a type of access right for a file?
A) Compile
B) Execute
C) Format
D) Mount
Execute
85
An Access Control List (ACL) provides a more granular way to:
A) Specify file types
B) Define protection settings, specifying permissions for multiple users and groups
C) Organize files into directories
D) Access files sequentially
Define protection settings, specifying permissions for multiple users and groups
86
A File Control Block (FCB) or inode contains:
A) The actual data content of the file
B) Information about a file, such as permissions, size, and location of data blocks
C) The boot instructions for the operating system
D) A list of all users who have accessed the file
Information about a file, such as permissions, size, and location of data blocks
87
Which layer in a layered file system is responsible for translating logical block numbers to physical block numbers and managing free space?
A) Device Driver layer
B) Basic File System layer
C) File Organization Module
D) Logical File System layer
File Organization Module
88
The Logical File System layer is primarily responsible for:
A) Low-level hardware commands
B) Managing metadata, including file control blocks and directory structures
C) Controlling physical I/O devices
D) Buffer and cache management
Managing metadata, including file control blocks and directory structures
89
A boot control block (often the first block of a volume) contains:
A) The entire file system directory
B) Information needed by the system to boot an OS from that volume
C) A list of all free blocks on the volume
D) User data files
Information needed by the system to boot an OS from that volume
90
A volume control block (or superblock) typically stores:
A) The code for device drivers
B) Details about the volume, like total blocks, free blocks, and block size
C) The contents of recently accessed files
D) Per-process open file information
Details about the volume, like total blocks, free blocks, and block size
91
When a file is opened, its FCB is typically copied from disk into which in-memory structure?
A) Per-process open-file table
B) Mount table
C) System-wide open-file table
D) Boot control block
System-wide open-file table
92
A major disadvantage of using a simple linear list for directory implementation is:
A) It's difficult to program
B) Linear search time can be slow for large directories
C) It cannot handle long file names
D) It consumes excessive memory
Linear search time can be slow for large directories
93
Contiguous allocation of disk blocks for a file offers:
A) No external fragmentation
B) Best performance for sequential and direct access in most cases
C) Easy file size extension
D) Automatic handling of bad blocks
Best performance for sequential and direct access in most cases
94
A significant problem with contiguous allocation is:
A) Slow sequential access
B) Internal fragmentation
C) External fragmentation and the need for compaction
D) Difficulty in direct access
External fragmentation and the need for compaction
95
Extent-based file systems allocate disk blocks:
A) One block at a time, linked together
B) In contiguous blocks called extents; a file consists of one or more extents
C) Using an index block for every file
D) Randomly across the disk
In contiguous blocks called extents; a file consists of one or more extents
96
In linked allocation for files:
A) All blocks of a file are contiguous on disk
B) Each block contains a pointer to the next block of the file
C) An index block stores pointers to all data blocks
D) The File Allocation Table (FAT) is not used
Each block contains a pointer to the next block of the file
97
A File Allocation Table (FAT) is essentially:
A) A per-file index block
B) A table at the beginning of the volume, indexed by block number, where entries form linked lists for files
C) A bit map representing free and allocated blocks
D) A directory structure that uses hashing
A table at the beginning of the volume, indexed by block number, where entries form linked lists for files
98
Indexed allocation for files involves:
A) Each file having its own index block(s) containing pointers to its data blocks
B) Linking data blocks directly to each other
C) Storing all file data contiguously
D) Using a hash table to find file blocks
Each file having its own index block(s) containing pointers to its data blocks
99
For very large files, a multi-level indexing scheme might be used to:
A) Reduce the number of data blocks
B) Avoid needing a large, contiguous index block by indexing the index blocks themselves
C) Improve sequential access performance significantly
D) Store file attributes more efficiently
Avoid needing a large, contiguous index block by indexing the index blocks themselves
100
The UNIX UFS (Unix File System) uses a combined allocation scheme that typically includes:
A) Only contiguous allocation
B) Only linked allocation
C) Direct blocks, single indirect, double indirect, and triple indirect blocks in the inode
D) A FAT for all file block tracking
Direct blocks, single indirect, double indirect, and triple indirect blocks in the inode
101
A bit map for free-space management represents each disk block as:
A) A pointer in a linked list
B) An entry in a hash table
C) A bit (0 for free, 1 for allocated, or vice-versa)
D) An extent of a certain size
A bit (0 for free, 1 for allocated, or vice-versa)
102
What is "TRIM" in the context of NVM storage devices?
A) A command to physically shrink the size of a file
B) A mechanism for the file system to inform the NVM device that a page/block is free and can be garbage collected/erased
C) A utility to defragment NVM devices
D) A technique to reduce write amplification
A mechanism for the file system to inform the NVM device that a page/block is free and can be garbage collected/erased
103
A page cache, as opposed to a traditional buffer (disk) cache, caches:
A) Disk sectors rather than logical blocks
B) Pages of virtual memory, which can include memory-mapped I/O and file system I/O
C) Only file metadata and directory entries
D) Only data from NVM devices
Pages of virtual memory, which can include memory-mapped I/O and file system I/O
104
A unified buffer cache aims to:
A) Use separate caches for memory-mapped I/O and regular file system I/O
B) Use the same page cache for both memory-mapped pages and ordinary file system I/O to avoid double caching
C) Cache only executable files
D) Increase the physical size of the disk cache
Use the same page cache for both memory-mapped pages and ordinary file system I/O to avoid double caching
105
Log-structured or journaling file systems improve recovery by:
A) Recording each metadata update as a transaction in a log before applying it to the main file system structures
B) Performing consistency checks more frequently
C) Eliminating the need for backups
D) Storing all file data in a sequential log
Recording each metadata update as a transaction in a log before applying it to the main file system structures
106
The WAFL (Write Anywhere File Layout) file system is known for:
A) Storing all data contiguously
B) Optimizing for random I/O and write operations, often using NVRAM for write caching and supporting snapshots
C) Being a read-only file system
D) Using a simple linked allocation scheme
Optimizing for random I/O and write operations, often using NVRAM for write caching and supporting snapshots
107
Synchronous writes ensure that:
A) Data is written to the cache, and acknowledgment is immediate
B) Data must be written to the physical disk before acknowledgment is sent
C) Writes are always performed in parallel
D) Multiple write operations are bundled together
Data must be written to the physical disk before acknowledgment is sent
108
"Free-behind" and "read-ahead" are techniques to optimize:
A) Random access performance
B) Sequential access performance
C) Directory lookup times
D) Free space management
Sequential access performance
109
A disk partition that is "raw" means:
A) It is formatted with a FAT file system
B) It is a sequence of blocks with no file system structure imposed on it
C) It contains only unformatted text files
D) It can only be accessed by the root user
It is a sequence of blocks with no file system structure imposed on it
110
The root partition of an operating system typically contains:
A) Only user data files
B) The operating system files and is mounted at boot time
C) Swap space exclusively
D) Only temporary files
The operating system files and is mounted at boot time
111
Virtual File Systems (VFS) provide an abstraction layer that:
A) Allows the same system call interface to be used for different types of underlying file systems
B) Manages virtual memory for file operations
C) Creates virtual disk drives in memory
D) Directly controls the physical disk hardware
Allows the same system call interface to be used for different types of underlying file systems
112
In a VFS implementation like Linux's, objects like inodes and files have a pointer to a function table. This table contains:
A) The data content of the file
B) Addresses of routines to implement generic operations (like open, read) for that specific file system type
C) A list of users who have permission to access the object
D) Hardware-specific commands for the disk controller
Addresses of routines to implement generic operations (like open, read) for that specific file system type
113
A distributed file system (DFS) allows:
A) Only local file access
B) Remote directories to be visible and accessed as if they were local
C) A file system to be distributed across multiple local disks for RAID
D) The file system to be stored entirely in volatile memory
Remote directories to be visible and accessed as if they were local
114
The Domain Name System (DNS) is a distributed information system primarily used for:
A) User authentication
B) Translating host names to network addresses
C) Storing file content
D) Managing file permissions across a network
Translating host names to network addresses
115
Lightweight Directory Access Protocol (LDAP) is often used as a:
A) File transfer protocol
B) Secure distributed naming and directory service mechanism
C) Disk formatting utility
D) Local file system type
Secure distributed naming and directory service mechanism
116
The Sun Network File System (NFS) specification distinguishes between:
A) Read and write operations
B) Services provided by a mount mechanism and actual remote-file-access services
C) Local and remote users
D) TCP and UDP protocols
Services provided by a mount mechanism and actual remote-file-access services
117
In NFS, what does a server's "export list" specify?
A) The list of users allowed to access the server
B) Local file systems that the server exports for mounting and which machines can mount them
C) The types of files that can be stored on the server
D) The network protocols supported by the server
Local file systems that the server exports for mounting and which machines can mount them
118
When an NFS client successfully mounts a remote directory, the server returns a:
A) User password
B) File handle, which is a key for further accesses
C) Complete copy of the directory contents
D) Security certificate
File handle, which is a key for further accesses
119
NFS V3 servers are generally characterized as "stateless," meaning:
A) They maintain extensive information about client connections
B) Each client request must provide a full set of arguments, as the server doesn't keep track of past requests from that client
C) They cannot handle file locking
D) They do not support caching
Each client request must provide a full set of arguments, as the server doesn't keep track of past requests from that client
120
The External Data Representation (XDR) protocol is used in NFS to:
A) Encrypt all network traffic
B) Achieve independence from machine, OS, and network architectures by defining a standard data format
C) Compress files before transmission
D) Manage user authentication
Achieve independence from machine, OS, and network architectures by defining a standard data format
121
In the NFS architecture, the VFS layer's role includes:
A) Directly communicating with the disk hardware
B) Distinguishing between local and remote files and dispatching operations accordingly
C) Implementing the NFS network protocol
D) Managing user interface elements
Distinguishing between local and remote files and dispatching operations accordingly
122
To speed up NFS path-name translation, clients often use a:
A) Write-through cache for file data
B) Directory name lookup cache holding vnodes for remote directory names
C) Special hardware accelerator for lookups
D) Local copy of the server's entire file system
Directory name lookup cache holding vnodes for remote directory names
123
One potential issue with NFS V3's stateless nature regarding data consistency is that:
A) It requires complex client-side state management
B) Modified data must be committed to the server's disk before results are returned to the client, potentially losing client-side caching benefits for writes.
C) It cannot support multiple clients accessing the same file
D) It leads to frequent server crashes
Modified data must be committed to the server's disk before results are returned to the client, potentially losing client-side caching benefits for writes.
124
A key difference between UNIX semantics and AFS session semantics for file sharing is:
A) UNIX semantics make writes visible only at file close, while AFS makes them immediate.
B) AFS session semantics make writes visible only after the file is closed (to new sessions), while UNIX semantics make them immediately visible.
C) UNIX semantics do not allow file sharing, AFS does.
D) AFS does not use file locking, UNIX does.
AFS session semantics make writes visible only after the file is closed (to new sessions), while UNIX semantics make them immediately visible.
125
The "mount point" in a file system is:
A) The physical location of the disk drive
B) A directory in the existing file system hierarchy where a new file system is attached
C) A special file representing the entire disk
D) The first block of a partition used for booting
A directory in the existing file system hierarchy where a new file system is attached
