Operating systems PA
Which command is used to determine the number of lines in a file? copy dir wc del
wc
Which disk type provides direct access to a secondary storage device as an array of blocks with no file system? Boot Raw Virtual Swap
Raw
Which operating environment is used to run an embedded system? Mainframe Server Desktop Real-time
Real-time
What should be used to improve memory utilization when loading external references? Dynamic linking Static linking Swapping Compaction
Dynamic linking
An access matrix list of three domains and six objects is depicted in the following table: O1O2O3O4O5O6D1r rwx D2rwx rwxrr D3 rwxorwxrwxorwxrwxo What is the length of the shortest access list?
1
An access matrix list of three domains and six objects is depicted in the following table: O1O2 O3O4O5 O6D1r rwx D2rwx rwx rr D3 rwxorwx rwxorwx rwxo What is the length of the shortest capability list? 1 2 3 4
2
What is the physical memory size for an address size of 8 bits? 16 64 256 1,024
256
Which generation of computers were large-scale integrated circuits used to develop personal computers for desktop and laptop operating systems? 2nd 3rd 4th 5th
4th
What is the relationship between threads, processes, and global data? All threads within a process share the same copy of global data. All processes within a thread share the same copy of global data. Each thread within a process has its own copy of global data. Each process within a thread has its own copy of global data.
All threads within a process share the same copy of global data.
What is an advantage of swapping? Provides efficient usage of memory by deallocating dynamic space when processes complete and allocating memory at run time Provides efficient usage of memory by reducing external fragmentation on a computer Allows processes that load the same DLL at the same base address to share a single copy of the DLL in physical memory Allows computers to execute more processes than there is available physical memory on a computer
Allows computers to execute more processes than there is available physical memory on a computer
What is a system service? A component of an operating system responsible for memory management A set of files used to store and retrieve operating system configuration information A program designed for end-user execution in the operating system An application included with an operating system to provide functionality beyond the kernel
An application included with an operating system to provide functionality beyond the kernel
What is a critical section? An area of code that cannot be entered by a process while another process is executing a corresponding area of the code. An area of code that cannot be modified by the operating system. An area of code that can be entered by a process while another process is executing a corresponding area of the code. An area of code that can be modified by the operating system.
An area of code that cannot be entered by a process while another process is executing a corresponding area of the code.
What can be used to access Dropbox? Common Internet File System (CIFS) Internet Small Computer System Interface (iSCSI) Network-attached storage (NAS) Application programming interface (API)
Application programming interface (API)
A company needs to determine when a computer experiences a microprocessor interrupt that is the result of a division by zero. Which operating system (OS) service should be used? Communication Error detection Logging Deadlock detection
Error detection
Which technique is used to bypass user authentication? Buffer overflow Login spoofing Back door Phishing
Back door
Which free memory space management strategy allocates the smallest free partition that meets the requirement of the requesting process? Best fit First fit Next fit Worst fit
Best Fit
Which data structure represents the allocation status of each disk block? Queue Linked list Bitmap Binary tree
Bitmap
When should digests be used? Establishing an undeniable link between the document and its sender Accelerating document encryption Reducing encrypted document size Reducing computational complexity of document decryption
Establishing an undeniable link between the document and its sender
Which user authentication method has the form of a dialogue between user and system? One-time password Challenge-response Single sign-on Biometrics
Challenge-response
Which interface allows combining multiple programs using the output from one as the input to another? Graphical user interface (GUI) Voice-user interface (VUI) Command-line interface (CLI) Natural user interface (NUI)
Command-line interface (CLI)
A company needs to ensure consistent performance by decreasing the density of bits from inner tracks to outer tracks. Which hard disk method should be used? Constant angular acceleration Constant angular velocity Constant linear velocity Constant magnetic field
Constant angular velocity
What is partitioning? Changing the type of file system in a storage region Changing the size of blocks Reallocating blocks into a contiguous space Creating groups of blocks on secondary storage
Creating groups of blocks on secondary storage
What is a symmetric key algorithm? Data encryption standard (DES) Huffman code Hamming code Rivest-Shamir-Adleman (RSA)
Data encryption standard (DES)
What is the determining factor for sustained throughput in magnetic storage? Disk size Track seek time Data transfer rate Rotational latency
Data transfer rate
Which cyberattack prevents a legitimate user from accessing an application in a timely manner? Denial-of-service Information disclosure Unauthorized use Information destruction
Denial-of-service
What describes the difference between internal and external fragmentation? Choose 2 answers. External fragmentation occurs when memory blocks are divided into variable-sized partitions. External fragmentation occurs when memory blocks are divided into fixed-sized partitions. Internal fragmentation occurs when memory blocks are divided into fixed-sized partitions. Internal fragmentation occurs when memory blocks are divided into variable-sized partitions.
External fragmentation occurs when memory blocks are divided into variable-sized partitions. Internal fragmentation occurs when memory blocks are divided into fixed-sized partitions.
What is a page in memory management? Fixed-size contiguous block of a logical address space identified by a single number Fixed-size contiguous block of physical memory identified by a single number Variable-size noncontiguous block of physical memory identified by a single number Variable-size noncontiguous block of a logical address space identified by a single number
Fixed-size contiguous block of a logical address space identified by a single number
What are two locations where firmware can be stored? Choose 2 answers. Flash memory Read-only memory (ROM) Cache memory Dynamic random-access memory (DRAM)
Flash memory Read-only memory (ROM)
What is a direct memory access (DMA) controller? Program invoked by the driver to access main memory Hardware device allowing access of main memory without the CPU Hardware device used by the CPU to access main memory Program invoked by the CPU to access main memory
Hardware device allowing access of main memory without the CPU
Why are approximations used in place of the least-recently-used (LRU) algorithm? Higher precision Higher efficiency Selects longest unused pages Guarantees fewer page faults
Higher efficiency
What does the memory manager do that can lead to poor system performance? Choose 2 answers. Fails to allocate memory as needed, causing processes to crash Is unable to allocate contiguous free blocks as needed, causing processes to wait Suspends processes requesting memory, causing them to stop responding Is forced to compact memory so it can fulfill allocations, causing processes to wait
Is unable to allocate contiguous free blocks as needed, causing processes to wait Is forced to compact memory so it can fulfill allocations, causing processes to wait
What is used to determine the number of processes that can run concurrently? Memory segmentation Demand paging Scheduling Load control
Load control
A process is not attempting to enter the critical section (CS), but it is preventing other processes from entering the CS. Which situation was caused by this process? Concurrency Starvation Lockout Deadlock
Lockout
Which cyberattack technique is mitigated by using the CTRL+ALT+DEL key sequence in the Windows operating systems? Back door Information leaking Logic bomb Login spoofing
Login spoofing
A company requires a computing environment that supports high-volume data processing and the management of a large amount of storage. Which computing environment should the company use? Desktop Server Laptop Mainframe
Mainframe
What are the two measures of positioning time? Choose 2 answers. Moving the disk arm to the desired cylinder Rotating the desired sector to the disk head Transferring data from the disk to the host system Transferring data to and from the disk media
Moving the disk arm to the desired cylinder Rotating the desired sector to the disk head
Which technique is used to execute several jobs by time-sharing among them? Multitasking Multiprogramming Abstraction Virtualization
Multitasking
What is the benefit of asymmetric cryptography? Faster encryption and decryption operations No need to exchange secret keys Uses the same key for encryption and decryption Higher computational complexity of encryption and decryption
No need to exchange secret keys
What describes the 50% rule in external memory fragmentation? One-fourth of memory may be lost. One-fourth of memory is occupied. One-third of memory may be lost. One-third of memory is occupied.
One-third of memory may be lost.
Which type of CPU instruction sets are supported by the CPU user mode? Both privileged and non-privileged Neither privileged nor non-privileged Only privileged Only non-privileged
Only non-privileged
Which method does the operating system use to divide system memory into contiguous, equal-sized partitions? Fragmentation Relocation Paging Swapping
Paging
What is a thread? System component allowed to run a privileged instruction set Part of a process that can run concurrently with other parts Application providing a user interface to system calls Instantiation of a process with a unique identifier
Part of a process that can run concurrently with other parts
What are two effects of paging in the address space? Choose 2 answers. Permits the physical address of a process to be noncontiguous Divides the logical address space of a process into equal-sized partitions Creates unused address spaces called external fragmentation Divides the logical address space of a process into different-sized partitions
Permits the physical address of a process to be noncontiguous Divides the logical address space of a process into equal-sized partitions
Which technique involves requesting an unsuspecting user to disclose their credit card information on a fake website that looks legitimate? Logic bomb Login spoofing Phishing Trapdoor
Phishing
Which scheduling system should be used to stop a process that is currently running and select another process to run? Long-term Short-term Preemptive Non-preemptive
Preemptive
What causes a page fault? Modified bit is set to 0 Present bit is set to 1 Present bit is set to 0 Modified bit is set to 1
Present bit is set to 0
What is a key that is used by a recipient to decrypt a message encrypted with asymmetric encryption? Public Private Shared Hash
Private
What is a computer program in execution called? Trap Thread Task Process
Process
Which component is responsible for running and suspending tasks in a multitasking operating system (OS)? Memory manager Network manager Process manager Storage manager
Process manager
Which resource is virtualized by multitasking? Disk Memory Network Processor
Processor
What does each thread of a multi-threaded process use to access shared code? Kernel Application Program counter Stack pointer
Program counter
Which file attribute should be used to identify who can access a file? Location Protection Type Size
Protection
What provides asymmetric cryptography? Lempel-Ziv-Markov Algorithm (LZMA) Rivest-Shamir-Adleman (RSA) Data Encryption Standard (DES) Advanced Encryption Standard (AES)
Rivest-Shamir-Adleman (RSA)
Which latency waits for the requested data to pass under the drive head of a magnetic hard disk? Seek time Sector overhead time Peak transfer rate Rotational delay
Rotational delay
Which two techniques guard against unauthorized activities when running code written by others? Choose 2 answers. Sandboxing Compiling Compression Interpretation
Sandboxing Interpretation
Which scheduler is used to decide the ready processes that should run next on the CPU? Long-term Short-term Preemptive Non-preemptive
Short-term
What is an operating system (OS)? A. An application that runs on bare hardware B. An application that runs within a kernel C. Software that runs on bare hardware D. Software that runs within a kernel
Software that runs on bare hardware
Which step is completed first during an input/output (I/O) call? The direct memory access controller transfers data to kernel memory The interrupt handler signals device driver The process is placed on the wait queue The device driver allocates kernel buffer space
The process is placed on the wait queue
How do threads differ from processes? Threads may contain multiple processes. Threads execute portions of a program within a process. Processes are faster to destroy than threads. Processes execute portions of a program within a thread.
Threads execute portions of a program within a process.
What are the two properties of threads? Choose 2 answers. Using multiple processes within a thread is more efficient than using multiple threads Using multiple threads within a process is more efficient than using multiple processes User-level threads are faster to manage than kernel-level threads Kernel-level threads are faster to manage than user-level threads
Using multiple threads within a process is more efficient than using multiple processes User-level threads are faster to manage than kernel-level threads
