Operating Systes Flashcards
Which generation of computers were large-scale integrated circuits used to develop personal computers for desktop and laptop operating systems?
4th Generation, early 1970s
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?
A mainframe computing environment is often the best choice.
Mainframes are designed to handle large-scale processing and storage needs, offering high reliability, scalability, and security.
What is an operating system (OS)?
Software that runs on bare hardware
Which type of CPU instruction sets are supported by the CPU user mode?
Only non-privileged
What are two locations where firmware can be stored?
Choose 2 answers.
Flash memory
Read-only memory (ROM)
What is a system service?
An application included with an operating system to provide functionality beyond the kernel
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?
Error detection
Which interface allows combining multiple programs using the output from one as the input to another?
Command Line Interface (CLI)
Which cyberattack prevents a legitimate user from accessing an application in a timely manner?
Denial of Service
Which command is used to determine the number of lines in a file?
wc
Which operating environment is used to run an embedded system?
Real-time
What is a thread?
Part of a process that can run concurrently with other parts
What are the two properties of threads?
User-level threads are faster to manage than kernel-level threads.
Using multiple threads within a process is faster than using multiple processes
Which component is responsible for running and suspending tasks in a multitasking operating system (OS)?
Process manager
Which resource is virtualized by multitasking?
Processor
Which technique is used to execute several jobs by time-sharing among them?
Multiprogramming
What is a computer program in execution called?
Process
What is the relationship between threads, processes, and global data?
All threads within a process share the same copy of global data
What does each thread of a multi-threaded process use to access shared code?
program counter
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 code
How do threads differ from processes?
Threads execute portions of a program within a process
Which scheduler is used to decide the ready processes that should run next on the CPU?
Short-term, also known as the CPU scheduler
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?
Lockout
Which step is completed first during an input/output (I/O) call?
the process is placed on the wait queue
Which free memory space management strategy allocates the smallest free partition that meets the requirement of the requesting process?
Best fit
Which method does the operating system use to divide system memory into contiguous, equal-sized partitions?
Paging
What is the physical memory size for an address size of 8 bits?
256
What causes a page fault?
Present bit is set to 0
What should be used to improve memory utilization when loading external references?
Dynamic linking
Why are approximations used in place of the least-recently-used (LRU) algorithm?
Higher efficiency
What describes the 50% rule in external memory fragmentation?
1/3 of memory may be lost
What describes the difference between internal and external fragmentation?
Choose 2 answers.
Internal fragmentation occurs when memory blocks are stored in fixed-sized partitions.
External fragmentation occurs when memory blocks are stored in variable-sized partitions.
What does the memory manager do that can lead to poor system performance?
Choose 2 answers.
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.
What are two effects of paging in the address space?
Choose 2 answers.
Divides the logical address of space into equal-sized partitions.
Permits the physical address of a process to be noncontiguous.
What is a page in memory management?
Fixed-size contiguous block of a logical address space identified by a single number
What is used to determine the number of processes that can run concurrently?
Load control
What is an advantage of swapping?
Allows computers to execute more processes than what is available in the physical memory on the computer (by temporarily moving less used process or parts or processes to the disk)
Which file attribute should be used to identify who can access a file?
Protection
Which scheduling system should be used to stop a process that is currently running and select another process to run?
Preemptive
Which data structure represents the allocation status of each disk block?
Bitmap
41
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
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 velocity
Which disk type provides direct access to a secondary storage device as an array of blocks with no file system?
Raw
Which latency waits for the requested data to pass under the drive head of a magnetic hard disk?
Rotational delay
What is the determining factor for sustained throughput in magnetic storage?
Data transfer rate
What can be used to access Dropbox?
API (Application Programming Interface)
What is a direct memory access (DMA) controller?
Hardware device allowing access to the main memory without the CPU
What is partitioning?
Creating groups of blocks on secondary storage
Which technique involves requesting an unsuspecting user to disclose their credit card information on a fake website that looks legitimate?
Phishing
Which technique is used to bypass user authentication?
Back door
Which cyberattack technique is mitigated by using the CTRL+ALT+DEL key sequence in the Windows operating systems?
Login spoofing
Which user authentication method has the form of a dialogue between user and system?
Challenge Response
What provides asymmetric cryptography?
Rivest-Shamir-Adleman (RSA)
What is a symmetric key algorithm?
Data encryption standard (DES)
An access matrix list of three domains and six objects is depicted in the following table:
O1 O2 O3 O4 O5 O6
D1 r rwx
D2 rwx rwx r r
D3 rwxo rwx rwxo rwx rwxo
What is the length of the shortest capability list?
2
Which two techniques guard against unauthorized activities when running code written by others?
Choose 2 answers.
Sandboxing
Interpretation
What is a key that is used by a recipient to decrypt a message encrypted with asymmetric encryption?
Private
What is the benefit of asymmetric cryptography?
No need to exchange keys (each party has their own beforehand)
When should digests be used?
Establishing an undeniable link between the document and its sender
