CSCE 3613: Operating Systems Final
An instance of executing a portion of a program within a process without incurring the overhead of creating and managing separate PCBs
Thread
An efficient method for executing a portion of a program is known as using ____?
Threads
Which is an example of a type of attack that occurs when a user opens a malicious executable supplied under the guise of a legitimate program?
Trojan Horse
The sum of the total CPU time and the waiting time is called ___?
Turnaround time
The act of creating the illusion of having one or more objects with more desirable characteristics than the real object. Uses abstraction, but emphasizes diversification and replication by creating illusions of objects with more favorable characteristics.
Virtualization
Process p1 and p2 are sharing a resource r, which contains 3 units. Which set of operations result in a state transition where p2 is blocked? req=request; acq=acquire; rel=release a) req r,2 by p1 acq r,2 by p1 req r,2 by p2 b) req r,2 by p1 acq r,2 by p1 rel r,1 by p1 req r,2 by p2 c) req r,1 by p1 acq r,1 by p1 req r,2 by p2 d) req r,1 by p1 req r,2 by p2 acq r,2 by p2
a) req r,2 by p1 acq r,2 by p1 req r,2 by p2
A user opens Microsoft Word on a computer. As a result, what action does the OS perform? a) Creates a new process b) Transfers process control c) Creates a context switch d) Changes the CPU state e) Sends an interrupt
a) Creates a new process
Which technique improves system resource utilization by holding active programs in memory while the programs wait for I/O completion or for an event to take place? a) Multiprogramming b) Abstraction c) Time-sharing d) Sequential Execution e) Multitasking
a) Multiprogramming
A system that uses multiprocessors is capable of carrying out operations in which way? a) Parallel b) Embedded c) Interconnected d) Virtualization e) None of the above
a) Parallel
An application can be structured as a collection of cooperating processes. Which of the following is not an advantage of the approach? a) Program size is deceased b) Processes can be studied in isolation c) CPU idle time may decrease d) Multiple CPUs may be used
a) Program size is decreased
Identify the term that describes a set of pages that will be needed in the immediate future and as a result, should be considered resident. a) The optimal working set b) The physical memory set c) The resident set d) the page-fault-frequency
a) The optimal working set
What is the concept of unification and simplification in computer science that combines simple objects into more complex object called? a) abstraction b) utilization c) virtualization d) execution e) minimalization
a) abstraction
The earliest deadline first (EDF) algorithm schedules processes according to the shortest remaining time until the process _______. a) deadline b) start c) arrival time d) departure time
a) deadline
What scheduling algorithm assigns new processes to the highest-level priority queue for scheduling and then moves processes to different queues depending upon how much CPU time the processes use during their execution? a) multilevel feedback b) interactive c) round-robin d) multilevel
a) multilevel feedback
What is a technique that keeps several programs active in memory and switches execution among the different programs to maximize the use of CPU and other resource? a) multiprogramming b) time-sharing c) multitasking d) parallelism e) shortest job first
a) multiprogramming
Recovery from deadlock is possible by destroying one or more of the ____ involved in the deadlock or by removing some of the ____ held by the deadlocked processes. a) processes, resources b) graphs, allocations c) claims, resources d) resources, edges
a) processes, resources
What is an interrupt triggered by the currently executing instruction call? a) trap b) swap c) software interrupt d) DMA e) kernel dump
a) trap
The PCB contains an up-to-date copy of the CPU state of a process p ______. a) when p's state is ready or blocked b) when p's state is running c) at all times
a) when p's state is ready or blocked
A semaphore used for mutual exclusion has an initial value of _____. a) null b) 1 c) -1 d) 0
b) 1
Process P1 and P2 execute on a system with a single CPU and two identical I/O devices. Each process executes a compute-bound phase followed by an I/O-bound phase. The system uses multiprogramming *without time-sharing.* The following table shows the lengths of each phase in ms. P1 starts first at time 0. If multiprogramming is used, when does all compute and I/O activities terminate? a) 160 b) 100 c) 140 d) 70 e) 90
b) 100
Using threads rather than multiple processes avoids the need for ____? a) Instruction sequence b) Code replication c) Multiple CPUs d) Shared programs
b) Code replications
Which algorithm replaces the page that has been resident in memory the longest? a) Optimal page replacement algorithm b) FIFO algorithm c) Least-recently-used algorithm (LRU) d) Belady's algorithm
b) FIFO algorithm
Which algorithm schedules processes according to the additional CPU time needed at the time of the scheduling decision? a) Shortest Job First (SJF) b) Shortest Remaining Time (SRT) c) First-In-First-Out (FIFO) d) First-Come-First-Served (FCFS)
b) Shortest Remaining Time (SRT)
A computer system is running several applications. The system's ability to create the illusion of simultaneous execution of the applications is known as what? a) Multiprogramming b) Time-sharing c) Abstraction d) Virtualization e) Multicast
b) Time-sharing
when solving a bounded-buffer problem, ____ must not overtake _____ and access empty slots. a) processes, buffers b) consumers, producers c) buffers, processes d) producers, consumers
b) consumers, producers
A condition where a process is holding one resource and requesting another is known as ______. a) circular wait b) hold-and-wait c) strict ordering d) sequential ordering
b) hold-and-wait
What is the minimal set of functions necessary to manage the operating system resources safely and efficiently? a) applications b) kernel c) system calls d) daemons e) processes
b) kernel
The implementation of the high-level synchronization primitive, called a monitor, allows _____ process(es) to execute concurrently. a) two b) one c) five d) any number of
b) one
Which memory paging concept defines a contiguous block of logical address space? a) page frame b) page c) page table d) page number
b) page
A process at the head of a round-robin queue has the highest priority and runs for X milliseconds. What term is used to describe the total time value for X? a) unit b) quantum c) context d) algorithm
b) quantum
With the Rate Monotonic (RM) algorithm used in real-time operating systems, which of the following is true? a) The more variable the period, the lower the priority. b) The shorter the period, the higher the priority. c) The less predictable the period, the higher the priority. d) The longer the period, the higher the priority.
b) the shorter the period, the higher the priority
What is an efficient method for executing a portion of a program? a) states b) threads c) processes d) pointers
b) threads
Which concept maintains recent translations of logical addresses to frames in physical memory for faster retrieval? a) hit ration b) translation lookaside buffer (TLB) c) principle of locality d) address segmentation
b) translation lookaside buffer (TLB)
In the operating systems class, how many bytes are in 8 Gigabytes? a) 2^30 b) 8*10^9 c) 2^33 d) 2^20 e) 10^6
c) 2^33
For the following set of processes, when does P1 end assuming Shortest Remaining Time Scheduling? a) 5 b) 10 c) 6 d) 8
c) 6
______ is a program or a program component written in a language that is compiled into executable code. a) An object module b) A compiler module c) A source module d) A load module
c) A source module
Which parameter defines the time interval in which a repeating computation must be completed? a) Departure b) Deadline c) Period d) Arrival
c) Period
With single-unit resources, deadlock is avoided by preventing ____. a) a complete reduction of the resource claim graph b) allocations to blocked processes c) a cycle to form in the resource allocation graph d) blocked processes to make a new request
c) a cycle to form in the resource allocation graph
A system task was initiated by a user request and was executed by the system. What was used in the operating system to recognize this task as non-privileged? a) Sequential execution b) The operating system shell c) A special mode bit d) function call e) A digital signature
c) a special mode bit
What will the use of time-sharing do? a) speed up all computations b) improve resource utilization c) guarantee reasonable response to each computation
c) guarantee reasonable response to each computation
In cloud computing, what is the term for the service in which one or more virtual machines are provided to the user to load an OS and/or application(s)? a) software as a service b) platform as a service c) infrastructure as a service d) data as a service e) apps as a service
c) infrastructure as a service
*Three independent processes* are executing on three physical CPUs. If the number of CPUs is increased to four, what affect does this have on the speed of execution? a) increase b) decrease c) no affect
c) no affect
Which type of scheduling algorithm may stop a running process when a new process enters the Ready List? a) long-term b) non-preemptive c) preemptive d) blocking
c) preemptive
Which algorithm treats all processes as equals? a) multilevel feedback b) multilevel c) round-robin d) interactive
c) round-robin
A paged virtual memory with ____ creates several large address spaces per process. a) a modified bit b) a present bit c) segmentation d) demand paging
c) segmentation
How many bytes are in a Terabyte? a) 2^10 b) 2^20 c) 2^30 d) 2^40 e) 2^50
d) 2^40
Due to short running times, what kind of scheduling algorithm can real-time processes use instead of a preemptive algorithm? a) Multilevel Feedback (MLF) b) Shortest Remaining Time (SRT) c) Round-Robin (RR) d) First-In First-Out (FIFO)
d) First-In First-Out (FIFO)
What is a concept that determines when a process should enter the ready state and start competing for the CPU? a) Short-term scheduling b) Non-preemptive scheduling c) Preemptive scheduling d) Long-term scheduling
d) Long-term scheduling
When a page fault occurs and the time since the previous fault is greater than a constant d, the page-fault-frequency replacement algorithm removes which pages? a) All resident pages b) Pages in the resident set that cause the fewest page faults c) The page in the resident set that is least recently used d) Pages in the resident set that have not been referenced since the previous page fault
d) Pages in the resident set that have not been referenced since the previous page fault
Which algorithm schedules processes according to the total CPU time requirements? a) First-In First-Out (FIFO) b) Shortest Remaining Time (SRT) c) First-Come First-Serve (FCFS) d) Shortest Job First (SJF)
d) Shortest Job First (SJF)
Which processor type is assigned when multiple processes are execute using time-sharing? a) Multi-CPU b) Physical CPU c) Software CPU d) Virtual CPU
d) Virtual CPU
The solution to the dining-philosophers problem where all philosophers pick up the left fork first may lead to _____. a) slowdown b) exclusion c) lack of concurrency d) deadlock
d) deadlock
What is an advantage of user-level threads over kernel-level threads? a) ability to use multiple CPUs b) greater performance c) greater responsiveness d) faster creation and destruction
d) faster creation and destruction
The loss of usable memory space due to the mismatch between the page size and the size of a program is referred to as _____ fragmentation. a) logical b) physical c) external d) internal
d) internal
A Microsoft Windows DLL file is an example of which type of external object reference? a) swapping b) sharing c) compiling d) linking
d) linking
What type of software can be freely accessed, used, changed, and shared by anyone? a) proprietary b) patented c) pirated d) open source e) hacked
d) open source
A relocation register holds the _____ of a program in memory. a) size b) symbolic address c) logical starting address d) physical starting address
d) physical starting address
In what state is a process if it has the necessary resources but the CPU is not available? a) running b) new c) suspended d) ready
d) ready
Which of the following processes should be executed before an interactive or batch process is scheduled? a) multilevel b) round-robin c) dynamic d) real-time
d) real time
When the value of s in a general semaphore implementation is less than 0, s corresponds to _____. a) the semaphore value b) the number of producer buffers c) process states d) the number of blocked processes
d) the number of blocked processes
What is the term for transferring control of the CPU from one process to another called? a) CPU state b) Running State c) State transition d) Ready State e) Context Switch
e) Context Switch
An operating system is responsible for which task? a) Making a call to an application's function b) Performing machine instructions c) Expanding a database with additional fields d) Assigning a variable in a process e) Loading an application into memory
e) Loading an application into memory
What is a state of a process called when it has the necessary resources and control of the CPU? a) Ready b) New c) Blocked d) Suspended e) Running
e) Running
A _______ section of code cannot be entered by a process while another process is executing a corresponding segment of the code. a) mutual b) excluded c) deadlocked e) critical
e) critical
Two concurrent applications, a1 and a2, execute the sequence of instructions (j1, j2, j3) and (k1, k2, k3) respectively. Execution switches between the applications whenever a timeout interrupt occurs or when one application terminates. If a2 starts, and interrupts occur after instructions k1 and j1, then what is the order in which the 6 instructions will execute? a) j1, k1, j2, j3, k2, k3 b) k1, k2, k3, j1, j2, j3 c) j1, j2, j3, k1, k2, k3 d) k1, j1, j2, j3, k2, k3 e) k1, j1, k2, k3, j2, j3
e) k1, j1, k2, k3, j2, j3
What occurs when a program attempts to reference a non-resident page?
page fault
Consider the following set of processes, with the length of the CPU-burst time given in milliseconds and the given arrival times. Version 3 Calculate the Average Turnaround Time (ATT) of these processes using First-Come-First-Served (FCFS) scheduling. Circle your final answer.
(6 + 8 + 6 + 8)/ 4 = 6.5
Consider the following set of processes, with the length of the CPU-burst time given in milliseconds and the given arrival times. Version 1 and 2 Calculate the Average Turnaround Time (ATT) of these processes using First-Come-First-Served (FCFS) scheduling. Circle your final answer.
(7 + 9 + 8 + 11) / 4 = 8.75
What is the speedup gain for an application that has 10% serial component and two processing cores? Circle your final answer Version 3 -Answer- Formula: Sn+1 = 1 / S + (1-S/N) N = 2
1 / ( .10 + (1 - .10/ 2)) = 1 / 0.55 = 1.818
What is the speedup gain for an application that has 25% serial component and two processing cores? Circle final answer Version 1 and 2 -Answer- Formula: Sn+1 = 1 / (S+(1-S/N)) N: 2
1 / .25 + ((1 - .25)/2) = 1/0.625 = 1.6
With a single-unit resources, deadlock is avoided by preventing ______.
A cycle to form in the resource allocation graph
The concept of unification and simplification by combining simple objects into more complex objects is referred to as _____?
Abstraction
The CPU is always running one process at a time. Multiple processes can share a single CPU by taking turns. A _________ is the transfer of control from one process to another.
Context Switch
Which technique can be used to enforce non-repudiation?
Digital Signatures
_____ occurs over time as a result of several processes running on a system using pure segmentation
External Fragmentation
The third generation of computers featured this OS type
Interactive multi-user OS
An operating system is responsible for which task?
Loading an application into memory
Which technique improves system resource utilization by holding active programs in memory while the programs waiting for I/O completion or for an event to take place?
Multiprogramming
The requirement that only one process may execute in a CS is called _____.
Mutual Exclusion
An operating system tracks each process by utilizing which data structure to hold information
PCB
Which memory paging concept defines a contiguous block of physical memory space?
Page frame
A relocation register holds the _____ of a program in memory.
Physical starting address
A data structure that represents a resource. The specific implementation and the contents of the ___________ vary between different OSs but the following is a generic structure that can handle many types of resources:
Resource Control Block (RCB)
When an operating system loads, the operating system may present a command interpreter. What type of interface is the interpreter?
Shell
Which algorithm needs to implement an arbitration rule?
Shortest Job First (SJF), First-In First-Out (FIFO), Shortest Remaining Time (SRT)
Which algorithm schedules processes according to the CPU time needed at the time of the scheduling decision?
Shortest Remaining Time (SRT)
A small piece of code called a ____ is used to find and load a reference routine when required at runtime.
Stub
A computer system is using several applications. The system's ability to create the illusion of simultaneous execution of the applications is known as what?
TIme-Sharing
