CSC606 Modern Operating Systems

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caldreaming
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278349
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CSC606 Modern Operating Systems
Updated:
2014-08-01 23:15:42
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csc606 modern operating systems kernel api application architectures software thread multiprocessing client server virtual machines
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Textbook Referenced: Tanenbaum, A. S. (2008). Modern operating systems (3rd ed.). Upper Saddle River, New Jersey: Pearson Prentice Hall. -- A study of relation between architectures, system software, and application software. Topics include process, thread, and memory management issues, multiprogramming, timesharing, multithreading, multiprocessing, inter-process communication, synchronization, virtual machines, client-server systems, distributed systems and real time systems, resource allocation, shared resources, input-output, file systems, computer security, and related problems. The scope and limitations of current Operating Systems are considered.
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  1. What is an operating system?
    • -Software that runs in kernel mode (some aspects of operating systems do run outside the kernel)
    • -A resource manager
  2. T/F  Operating System software only runs in the kernel mode
    False; important features of operating systems often run outside the kernel
  3. Using a top-down view of “what” an Operating System is, we can say that it ____.

    A) Manages the pieces of a complex system
    B) Provides abstractions to applications that hide the “details” of resources and resource
    management
    C) Manages communications
    D) Is located in firmware
  4. To obtain services from the Operating System, a program makes a _______ which causes a trap to the kernel.

    A) Request
    B) System call
    C) Program Status Word
    D) Resource packet
    B) System call

    To obtain services from the operating system, a user program must make a system call, which traps into the kernel and invokes the operating system. 

    (Tanenbaum, 2008, p. 21)
    (this multiple choice question has been scrambled)
  5. According to the Week1 Overview, what is another definition of an Operating System?
    An operating system is hardware and or firmware that makes the hardware resources of the system usable.
  6. In order to create a child process with the same context as the parent (identical to), your program would issue the ____ System Call.

    A) exec
    B) create process
    C) passContext
    D) fork
    D) fork

    In computing, particularly in the context of the Unix operating system and its workalikes, fork is an operation whereby a process creates a copy of itself. It is usually a system call, implemented in the kernel. Fork is the primary (and historically, only) method of process creation on Unix-like operating systems.
    (this multiple choice question has been scrambled)
  7. In order to cause most of the Operating System to run in ‘safe’ user mode, you would design an Operating System as a ____.

    A) Client-Server
    B) Monolith
    C) Microkernel
    D) Series of layers
    C) Microkernel
    (this multiple choice question has been scrambled)
  8. If two states of process execution are ‘Running’ and ’Ready’, the third is ____.

    A) Sleeping
    B) Blocked
    C) In-Transition
    D) Signaled
    B) Blocked  (Tanenbaum, 2008, p. 90)

    There are 3 states that a process may be in;

    • 1. Running (Actually using the CPU at that instant
    • 2. Ready (Runnable; temporarily stopped to let another process run)
    • 3. Blocked (Unable to run until some external event happens)
  9. User level threads are implemented via ____.

    A) The interrupt structure
    B) The Operating System kernel
    C) The process itself
    D) A library of procedures to manage the threads
    D) A library of procedures to manage the threads  (Tanenbaum, 2008, p. 107)
    (this multiple choice question has been scrambled)
  10. Critical regions with processes require ____.

    A) Careful management
    B) Nothing
    C) Mutual exclusion
    D) Monitor management
    • C) Mutual exclusion  
    • (Tanenbaum, 2008, p. 136)
  11. Scheduling in an interactive system would probably be done by a ____ algorithm.

    A) Shortest Job First
    B) Round Robin
    C) First Come First Served
    D) Policy Scheduler
    B) Round Robin
    (this multiple choice question has been scrambled)
  12. In an Operating System the program that users typically interact with is called a _______.
    Shell
  13. What is a process?
    An abstraction of a running program - i.e. a program in a state of execution.
  14. Describe Symmetric Multiprocessing;
    When there are two or more processors connected to a single shared memory with a single OS.
  15. What is the definition of a network operating system?
    An operating system that allows users to login to remote machines and copy files from one to another.
  16. What is meant by the term, "hard real time"?
    An Operating System (OS) that will provide guarantees that actions will occur within a fixed time.
  17. What is Kernel Mode?
    Kernel Mode is when an Operating System (OS) has access to all hardware and can execute any instruction.
  18. What is a shell?
    The shell is a program that a user interacts with.
  19. What is virtual memory?
    Virtual memory utilizes both RAM and disk space as program memory, moving pieces of data back and forth between RAM and disk memory as needed for processing.
  20. What is a microkernel?
    A microkernel is a small Operating System (OS) that uses small modules, only one of which runs in kernel mode.
  21. What is meant by Process State?
    According to the textbook there are 3 process running states; Ready, Running or Blocked.  There is also a 5 state model which includes the New state when a program starts and the Exit or Terminate state when a program is shutting down.  Process state tells you whether a process in Running in the CPU, Ready and waiting for the CPU to be free for processing or Blocked waiting for input from the user or a lengthy procedure to finish.
  22. What is a PCB (Process Control Block)?
    To implement the Process Model, the operating system maintains a table called the Process Table with one row or tuple for each process.  Each of these tuples is known as a Process Control Block or PCB.  They contain information about the process state which include it's program counter, stack pointer, memory allocation, status of open files, accounting and scheduling information, and everything is needed to restart the process running from it's previous state.
  23. What are Producer Consumer Processes?
    Producer Consumer Processes are when two processes share a common buffer where one is producing while the other is consuming.
  24. What is a Kernel Thread?
    A Kernel Thread is a Thread managed by the Kernel.
  25. Describe a LWP (Light Weight Process);
    A light weight process is a Thread with some of the properties of a process.
  26. What are Pthreads?
    Pthreads are an IEEE standard for Thread creating and management.
  27. What is a User Thread?
    A User Thread is a Thread managed by a user level Thread management library.
  28. An address space is ____.       

    A) All of physical RAM
    B) The set of registers that a process can manipulate       
    C) The set of process’ mailboxes       
    D) The set of addresses that a process can use to address memory       
    D) The set of addresses that a process can use to address memory
    (this multiple choice question has been scrambled)
  29. Pages are mapped to page frames using the/a:

    A) I/O Management Unit       
    B) Segment table       
    C) Translation lookaside buffer
    D) Page Table       
    D) Page Table
    (this multiple choice question has been scrambled)
  30. The ‘Optimal’ Page Replacement strategy ____.       

    A) Is used for timesharing systems       
    B) Uses page size as a measure of ‘goodness’      
    C) Can only be used in Real Time systems      
    D) Impossible to implement
    D) Impossible to implement
    (this multiple choice question has been scrambled)
  31. An absolute pathname is the path starting at the ____.       

    A) Physical device
    B) Null file       
    C) Root directory       
    D) Parent directory       
    C) Root directory
    (this multiple choice question has been scrambled)
  32. Knowing the file size distribution in a system allows designers to choose a ______.       

    A) Good device driver       
    B) Good page size       
    C) Good disk scheduling algorithm       
    D) Good block size
    D) Good block size
    (this multiple choice question has been scrambled)
  33. Using a top-down view of “what” an Operating System is, we can say that it ____.       

    A) Manages the pieces of a complex system      
    B) Manages communications       
    C) Provides abstractions to applications that hide the “details” of resources and resource management       
    D) Is located in firmware
    C) Provides abstractions to applications that hide the “details” of resources and resource management
    (this multiple choice question has been scrambled)
  34. To obtain services from the Operating System, a program makes a _______ which causes a trap to the kernel.       

    A) Program Status Word
    B) System call       
    C) Request       
    D) Resource packet       
    B) System call
    (this multiple choice question has been scrambled)
  35. In order to create a child process with the same context as the parent (identical to), your program would issue the ____ System Call.

    A) fork
    B) create process       
    C) passContext       
    D) exec       
    A) fork
    (this multiple choice question has been scrambled)
  36. In order to cause most of the Operating System to run in ‘safe’ user mode, you would design an Operating System as a ____.       

    A) Client-Server
    B) Series of layers       
    C) Monolith       
    D) Microkernel       
    D) Microkernel
    (this multiple choice question has been scrambled)
  37. What is an interrupt and how does it work?
    • An interrupt is a hotline to talk to the CPU controller.
    • Step 1: The driver tells the interrupt controller what to do by writing into it's device registers.
    • Step 2: When the disk controller has finished writing the data into the interrupt controller registers it signals the interrupt controller it is done.
    • Step 3: The interrupt controller then informs the CPU controller and gives the device number through the bus so the CPU knows which device is finished.  

    Once the CPU has decided to take the interrupt, the program counter and the Program Status Word (PSW) are pushed into onto the current stack and the CPU started in kernel mode.
  38. What is "Busy Waiting" and what is it's major disadvantage?
    When an I/O device needs to run a lengthy process, the driver sits in a tight loop continuing polling the device to see if it is done.  when the I/O device finishes it's process it passes the data to the appropriate memory location and returns.  The OS then returns control to the caller.

    This process ties up the CPU keeping it busy polling the device until the process is finished.
  39. The operating system fits into the _______.

    A) Kernel Mode
    B) User Mode
    A) Kernel Mode

  40. T/F    The ugly interface is between the Operating System and the Application Programs.
    False.  The ugly interface is between the hardware and the Operating System.  The OS communicates with the hardware in machine language, also known as assembly language or binary.

  41. Which of the following is NOT true about the Operating System as a Resource Manager?

    A) Allow multiple programs to run at
    the same time

    B) Manage and protect memory, I/O
    devices, and other resources

    C) Includes multiplexing (sharing)
    resources in two different ways: time & space 

    D) Provides a web browser and e-mail reader without any other applications needed
    D) Provides a web browser and e-mail reader without any other applications needed
  42. To obtain services from the Operating System, a user program must make a ______  ______.
    System Call

    To obtain services from the Operating System, a user program must make a System Call.
  43. During a System Call, the ____ instruction switches from User Mode to Kernel Mode and starts the Operating System.
    Trap

    During a System Call, the TRAP instruction switches from User Mode to Kernel Mode and starts the Operating System.
  44. T/F  Generally, all instructions involving I/O and memory protection are disallowed in user mode.
    TRUE

    (Tanenbaum, 2008, p. 21, para. 3)
  45. T/F   A System Call is a special kind of procedure call instruction that has the additional property of switching from User Mode to Kernel Mode.
    True

    (Tanenbaum, 2008, p. 21, para. 4)
  46. Moore's Law states that;
    the number of transistors on a chip doubles every 18 months.

    This is an observation from Gordon Moore, Intel cofounder, of how fast transistors are able to shrink in production.

    (Tanenbaum, 2008, p. 22, para. 2)
  47. Which system call for process management creates a child process identical to the parent;

    A) fork
    B) waitpid
    C) execve
    D) exit
    A) fork

    (this multiple choice question has been scrambled)
  48. Register Memory resides in the CPU itself and has a typical capacity of _____  and a typical access time of _____.

    A) less than 1 KB, 1 nano second
    B) 512-2048 MB, 10 nano seconds
    C) 4 MB, 2 nano seconds
    D) 400-800 GB, 100 seconds
    A) less than 1 KB, 1 nano second


    The storage capacity within them is is typically 32x32 bits for a 32-bit CPU and 64x64 bits for a 64-bit CPU.  Less than 1 KB in both cases.
    (this multiple choice question has been scrambled)
  49. What is the name of the register that contains the condition code bits which are set by comparison instructions, the CPU mode (User or Kernel), the CPU priority and various other bits?
    PSW - Program Status Word

    (Tanenbaum, 2008, p. 20, para. 4)
  50. In addition to the general registers used to hold variables and temporary results, most computers have several special registers that are visible to the programmer.  Which register contains the memory address of the next instruction to be fetched and is later updated to contain the address of it's successor?

    A) Stack Pointer
    B) Program Counter
    C) PSW (Program Status Word)
    B) Program Counter

    (Tanenbaum, 2008, p. 20, para. 2)
  51. What CPU property allows the CPU to hold the state of two different threads and then switch back and forth on a nano second time scale?
    Multithreading or Hyperthreading


    (Tanenbaum, 2008, p. 22, para. 4)
  52. T/F  Multithreading allows true parallelism.
    False

    Multithreading does NOT allow true parallelism. Only one process at a time is running, but thread switching time is reduced to the order of a nano second.

    (Tanenbaum, 2008, p. 22, para. 4)
  53. T/F  Those instructions that affect control of the machine or do I/O are forbidden to User Mode programs.
    True

    (Tanenbaum, 2008, p. 2, para. 1)
  54. The Operating System is the most fundamental piece of software and runs in ______ ____.
    Kernel Mode

    (Tanenbaum, 2008, p. 1, para. 3)

  55. The file management system call the moves the file pointer is the call;
    Position = lseek(fd, offset, whence)

  56. The file management system call that gets a files status information is the call;
    s = stat(name, &buf)

  57. The file management System Call that removes a directory entry is the call;
    s = unlink(name)

  58. The file management System Call that mounts a file system is the call;
    s=mount(special, name, flag)

  59. The file management System Call that removes an empty directory is the call;
    s = rmdir(name)

  60. The miscellaneous System Call that changes the working directory is the call;
    s = chdir(dirname)

  61. The miscellaneous System Call that gets the elapsed time since Jan. 1, 1970 is the call;
    seconds = time(&seconds)

  62. What is the definition of a shell?
    A text based program that users can interact with.  The shell is not a part of the Operating System although it uses the Operating System to get its work done.

    (Tanenbaum, 2008, p. 1, para. 2)
  63. Most computers have two modes of operation;
    The Kernel Mode and the User Mode

    (Tanenbaum, 2008, p. 1, para. 3)
  64. What are the threes segments of a process?
    Text, Data and Stack

  65. T/F   Monolithic systems have a basic structure consisting of;

    A main program that invokes the
    requested service procedure.

    A set of service procedures that
    carry out the system calls.

    A set of utility procedures that
    help the service procedures.
    True

  66. The 6 layers of layered systems are;

    Clue:  PMOIUP
  67. What does DMA stand for?
    Direct Memory Access
  68. What does PSW stand for?
    Program Status Word
  69. What is Direct Memory Access (DMA)?
    Direct Memory Access does some of the work for the CPU.  DMA is a chip that can control the flow of bits between memory and controllers without constant CPU intervention.  The CPU sets up the DMA chip telling it how many bytes to transfer, the device and memory addresses involved, and the direction; then lets go.  When the DMA chip is done it causes and interrupt.
  70. T/F    In multiprogramming models all programs are active at the same time.
    False.  Only one program is active at a time and they share the CPU based on a scheduling model.

  71. What are the 4 events that can cause process creation?
    1) System initialization.

    • 2) Execution of a process creation
    • system call by a running process.

    • 3) A user request to create a new
    • process.

    4) Initiation of a batch job.
  72. What are the 4 ways in which processes can be terminated?

    Clue: NEFK
    1) Normal exit (voluntary).

    2) Error exit (voluntary).

    3) Fatal error (involuntary).

    • 4) Killed by another process
    • (involuntary).
  73. T/F    In regards to a running process termination, a Normal exit and an Error exit are voluntary.
    True, these are voluntary.

    • Events which cause process termination:
    • Normal exit (voluntary).
    • Error exit (voluntary).
    • Fatal error (involuntary).
    • Killed by another process
    • (involuntary).
  74. T/F    In regards to a running process termination, a Fatal error and a process Killed by another process are voluntary exits.
    False, these are involuntary.

    • Events which cause process termination:
    • Normal exit (voluntary).
    • Error exit (voluntary).
    • Fatal error (involuntary).
    • Killed by another process(involuntary).
  75. T/F     In regards to a running process termination, a Fatal error and a process Killed by another process are involuntary exits.
    True, these are involuntary.

    • Events which cause process termination:
    • Normal exit (voluntary).
    • Error exit (voluntary).
    • Fatal error (involuntary).
    • Killed by another process(involuntary).
  76. The 3 process states are _____,  _____  and ______.
    Running, Ready and Blocked.
  77. When a process in a blocked state needs CPU time to continue processing, it returns to the _______ state next.

    A) Running
    B) Next
    C) Ready
    D) Blocked
    E) New
    C) Ready

    • There are 3 ways to get to the Ready State;
    • 1) New -> Ready
    • 2) Blocked -> Ready
    • 3) Running -> Ready
  78. T/F     The Blocked state is also known as the Wait State.
    True.
  79. T/F    Threads can share stacks.
    False.

    Every thread has it's own stack.  

    The stack is where we keep the local variable values that are in memory.  Parameters, local variables and how to get back to the calling function are all saved in the stack.
  80. What is the job of the process scheduler?
    The process scheduler decides which process is to run next.
  81. T/F    Global variables are call inside of a function.
    False.

    • Global Variables are called outside of a function.
    • Local Variables are call inside of a function.
  82. T/F    Local Variables are call inside of a function.
    True.

    • Local variables are called within a function.
    • Global variables are call outside of a function.
  83. What is the entry point for a C program?
    The Main Function is the entry point for a C program.
  84. What is a program?
    A program is a set of instructions. 
  85. What is the purpose of the program counter?
    The program counter points to the next instruction to process.  It also tracks where a program is in the process.
  86. T/F     In a single CPU only one program is active at a time.
    True.
  87. T/F    In UNIX, only FORK creates a new process.
    False.

    In Unix, both FORK and EXEC create a new process.
  88. The 3 states discussed in the class textbook are Running, Ready and Blocked but there is also a 5 state model.  What are the other two states not discussed in the textbook?
    • New State - When a program is starting up.
    • Terminate State - When a program is shutting down.
  89. An Interrupt is a mechanism to get the systems attention.  What are the two typical characteristics of an Interrupt?
    • 1. An Interrupt Number
    • 2. An Interrupt Service Routine
  90. Where threading is concerned, what are the 3 ways to construct a server?
  91. What is address space?
    The set of addresses that a process can use to address memory.

    Associated with each process is its address space, a list of memory locations from 0 to some maximum, which the process can read and write.  The address space contains the executable program, the programs data, and its stack.

    (Tanenbaum, 2008, p. 38, para. 1)
  92. What is swapping?
    Bringing an entire process into memory, let it run for a while, then move it back to disk space.
  93. What is Memory Compaction?
    Memory compaction is when a computer combines multiple holes in memory by moving all processes to one end of memory.
  94. What is a page frame?
    A page frame is a fixed size block of memory.
  95. What is a page table?
    A Page Table is an operating system structure providing a mapping between virtual page numbers and page frame numbers.
  96. What is the Translation Look-Aside Buffer?
    A Translation Look-Aside Buffer is hardware associative memory with a small number of entries used to map page number to frame number.
  97. What is an inverted page table?
    An inverted page table is a page table with one entry per page frame but not the virtual pages.
  98. What capabilities are provided by the use of Virtual Memory?
    Virtual Memory allows programs to run when only partially loaded in memory.
  99. What is a page fault?
    A Page Fault is a trap that occurs when a page is on disk and needed in RAM.
  100. What is a regular file?
    Any file that contains user data.
  101. What is a hierarchical directory system?
    A hierarchical directory system is a tree of directories used to group files in logical, natural ways.
  102. What is an inode?
    An inode is a structure containing file attributes and addresses of a files disk blocks.
  103. What is a File Allocation Table (FAT)?
    A File Allocation Table is a linked list allocation with entries chained together in a table located in main memory.
  104. What is a file descriptor?
    File descriptors are small integers returned when a file is opened (UNIX) then used to access and work with the file.
  105. What is Linked List Allocation?
    Linked List Allocation is a linked list of disk blocks with the first word of a block that acts as a pointer to the next one.
  106. T/F      A process is basically a program in execution.
    True

    (Tanenbaum, 2008, p. 38, para. 1)
  107. T/F  A process is fundamentally a container that holds all the information needed to run a program.
    True

    (Tanenbaum, 2008, p. 38, para. 1)
  108. What is interprocess communication?
    Related processes that are cooperating to get some job done often need to communicate with one another and synchronize their activities.  This communication is called interprocess communication

    (Tanenbaum, 2008, p. 39, para. 1)
  109. What is the term for dealing with memory overload when more processes are running than can be accommodated by physical RAM?
    Swapping

    Swapping consists of bringing each process into RAM in it;s entirety (if it fits), running it for awhile, then putting it back on the disk.

    (Tanenbaum, 2008, p. 182, para. 2)
  110. When a process is too large to bring into existing physical RAM, what other strategy can be used for dealing with memory overload?
    Virtual Memory

    Virtual memory allows programs to run even when they are only partially in main memory.  The process is loaded until RAM is full and then the remaining part of the process is kept in the hard disk that behaves as if it is a part of main memory.  The drawback is that virtual memory requires reading from the disk which is much slower than reading from RAM. 

    (Tanenbaum, 2008, p. 182, para. 2)
  111. What are the two strategies for dealing with memory overload?
    • 1) Swapping
    • 2) Virtual Memory
  112. T/F     Memory allocation never changes as processes come into memory.
    False

    Memory allocation changes as processes come into memory and leave it.  When swapping creates multiple holes in memory it is possible to combine them all by moving processes downward as far as possible.  This technique is known as memory compaction

    (Tanenbaum, 2008, p. 183, para. 2)
  113. Describe the skeleton (8 steps) of what the lowest level of the operating system does when an interrupt occurs;

    Clue:  HHAACSCA
    • 1) Hardware stacks program counter, etc.
    • 2) Hardware loads new program counter from 
    •      interrupt vector.
    • 3) Assembly language procedure saves    
    •      registers.
    • 4) Assembly language procedure sets up new
    •      stack.
    • 5) C interrupt service runs (typically reads
    •      and buffers input).
    • 6) Scheduler decides which process is to run
    •      next.
    • 7) C Procedure returns to the assembly code.
    • 8) Assembly language procedure starts up
    •      new current process.
  114. What is a binary semaphore?
    Semaphores that are initialized to one and used by two or more processes to ensure that only one of them can enter its critical region at the same time are called binary semaphores.
  115. What is a Mutex?
    A mutex is a variable that can be in one of two states: unlocked or locked.
  116. A memory mapped I/O system occurs when ____.       

    A) Device controllers have no registers - they are in memory       

    B) Device controllers can’t respond to interrupts – only memory  
         
    C) Device controller control registers are accessed through unique memory locations  

    D) Device controllers aren’t accessible through DMA
    C) Device controller control registers are accessed through unique memory locations
  117. The layer of I/O software ‘closest’ to the hardware is the ____ layer.

    A) Device driver       
    B) User level       
    C) Operating system software
    D) Interrupt handler       
    D) Interrupt handler
    (this multiple choice question has been scrambled)
  118. When scheduling disk access requests, the ____ algorithm maintains the current direction of head movement.       

    A) First Come First Served       
    B) Elevator
    C) Round Robin       
    D) Shortest Seek First       
    B) Elevator
    (this multiple choice question has been scrambled)
  119. One of the four conditions for deadlock, the No Preemption Condition states that ____. 

    A) Processes wait for resources in a circular chain
    B) Processes hold resources while waiting for others       
    C) Each resource can be assigned to only one process       
    D) Resources being held cannot be taken away       
    D) Resources being held cannot be taken away
    (this multiple choice question has been scrambled)
  120. The ____ checks to see if allocating a resource would result in an Unsafe state.       

    A) Banker’s Algorithm       
    B) Acrylic edge graph       
    C) Directed graph       
    D) Resource trajectory graph
    A) Banker’s Algorithm
    (this multiple choice question has been scrambled)
  121. Error interrupts are also called ______.
    Traps
  122. Sometimes the normal flow of a program is required to stop and process an event that requires a prompt response.  The hardware of a computer provides a mechanism called __________ to handle these events.
    Interrupts

    • External interrupts are raised from outside the CPU. (The mouse is an example of this type.) Many I/O devices raise interrupts (e.g., keyboard, timer, disk drives, CD-ROM and sound cards). Internal interrupts are raised
    • from within the CPU, either from an error or the interrupt instruction. Error interrupts are also called traps. Interrupts generated from the interrupt instruction are called software interrupts.
  123. Interrupts cause control to be passed to an ______   ________.
    Interrupt Handler.

    Interrupt handlers are routines that process the interrupt. Each type of interrupt is assigned an integer number. At the beginning of physical memory, a table of interrupt vectors resides that contain the segmented addresses of the interrupt handlers. The number of interrupt is essentially an index into this table.
  124. To obtain services from the Operating System, a program makes a _______ which causes a trap to the kernel. 

    A) Resource packet  
    B) Program Status Word
    C) Request  
    D) System call  
    D) System call
    (this multiple choice question has been scrambled)
  125. If two states of process execution are ‘Running’ and ’Ready’, the third is ____. 

    A) Signaled
    B) Blocked  
    C) In-Transition  
    D) Sleeping  
    B) Blocked
    (this multiple choice question has been scrambled)
  126. What is the term for CPU-memory pairs connected by a high-speed interconnect with communication latencies of 10-50 micro seconds?
    Tightly coupled systems
  127. What is the term for NonUniform Memory Access multiprocessors with some memory words that can be read faster than others?
    NUMA processors
  128. What is it called when one CPU core modifies a word and it is automatically removed from all caches?
    Snooping (as applied to cache management for multi-core chips)
  129. What is the term for a multiprocessor system with all CPU’s sharing one copy of the operating system in a shared memory with one set of operating system tables?
    Symmetric MultiProcessor
  130. What is the term for Tightly coupled systems that do not share memory communicate via packets that are copied from input buffer to input buffer?
    Store-and-forward packet switching
  131. What is a technique allowing programs on one machine to call procedures located on other CPU’s?
    Remote procedure call
  132. What is the term for Algorithms used to assign processes to nodes of a multicomputer system designed to minimize wasted CPU cycles, or to minimize total communication bandwidth?
    Processor allocation algorithms
  133. What is a transfer model defining how file-system-based middleware in a distributed system provides file access to remote nodes?
    Upload/download model
  134. What is the term for object-based middleware that make it possible for a client on one platform to access a server on a different platform?
    Object request broker
  135. What is the term for a type of distributed system wherein computers run a common layer of middleware that allows programs to access all the resources of the system?
    Grid
  136. What is the term for a definition of system objects that need to be protected and a set of permissions describing allowed operations? (There can be/are multiple domains in a system).
    Protection domain
  137. What is the term that defines a protection domain by associating with each protected object a list containing all the domains (process/user) that may access an object and what they can do?
    Access Control List (ACL)
  138. What is the term for the set of system hardware and software required to enforce all security rules?  This would be most of the hardware, a portion of the kernel, and all user programs that have superuser (Unix) power.
    Trusted computing base
  139. What is the term for a security intrusion that exploits fixed sized buffers on the stack by writing excessive data (to include a program) to a location and providing a bogus return address.
    Buffer overflow attack
  140. What is the term for a web service provided by Amazon Web Services that provides a resizable computing capacity to ‘cloud’ users?
    Elastic Compute Cloud
  141. What is the term for a device storing information in fixed size blocks, each with its own address?
    Block device
  142. What is the term for a technique allowing CPU-Device Controller communication through registers mapped into the memory space?
    Memory mapped I/O
  143. What is the process that transfers data from a device to memory using a dedicated controller with direct access to memory?
    Direct Memory Access (DMA)
  144. What is the term for an OS table that provides a mapping from a device number to an interrupt service procedure?
    Interrupt vector
  145. What is 'Programmed I/O'?
    After outputting a character, the CPU polls the device to see when it is ready for the next one.
  146. What is meant by 'Major device number'?
    In a Unix system, a value in a special file inode used to locate the device driver.
  147. What is a 'circular buffer'?
    A region of memory with two pointers, one indicating the next free word, the other the next word of data.
  148. What is a 'daemon'?
    A process with exclusive access to a device special file that processes entries in a spooling directory.
  149. The time required to move a disk arm to the proper cylinder is called;
    Seek time
  150. A disk scheduling algorithm that processes requests in a preferred direction is called a;
    Elevator algorithm
  151. A resource that can be taken away from its current owner with no ill effects is called;
    Preemptable resource
  152. A directed graph of processes and resources with arcs designating resource ownership is called;
    Resource allocation graph
  153. What is 'rollback'?
    Used when deadlock is detected to roll a process back to a previous checkpoint, thus freeing a resource.
  154. What is meant by 'safe state'?
    A current state of processes and scheduling order guaranteeing that all processes will be able to run to completion.
  155. Describe the 'bankers algorithm';
    A scheduling algorithm used to allocate resources and guaranteeing that an allocation will not result in an unsafe sate.
  156. Describe the arm movement for a magnetic disk that is called 'Circular Scan' (also known as C-Scan);
    The disk heads read in only one direction then returns without stopping/reading.  Then the heads start all over again reading at the beginning.
  157. Describe the arm movement for a magnetic disk that is called 'Elevator Scan' (also known as Scan);
    The arm only moves in one direction at a time, reading from one side to the end and then reverses.  The heads read in both directions but do not alter direction until reaching the end of the platter.
  158. Name the 3 ways to organize files systems;
    Contiguous, Link List and I-nodes.

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