INT-1700 Study Guide 2

Fill in the missing step in the following deadlock situation. Two users from the local board of education are each running a program (P1 and P2), and both programs will eventually need two DVD drives to copy files from one disc to another. Only two DVD-R drives are available and they’re allocated on an “as requested” basis. Soon the following sequence transpires:
1. P1 requests drive 1 and gets it.
2. ____
3. P1 requests drive 2 but is blocked.
4. P2 requests drive 1 but is blocked.

The operation P in a semaphore scheme requires a(n) ____ sequence to be performed as an indivisible action in a single machine cycle.

Deadlock can occur on a printer when ____.

The ____ is also called a high-level scheduler.

No movement between queues is a very simple policy that rewards those who have ____ jobs.

____ is necessary in any computer system because some resources such as memory, CPU, and dedicated devices must be exclusively allocated to one user at a time.

The Printer Event
1 P1 requests and is allocated the printer R1.
2 P1 releases the printer R1.
3 P2 requests and is allocated the disk drive R2.
4 P2 releases the disk R2.
5 P3 requests and is allocated the plotter R3.
6 P3 releases the plotter R3.


Assume that the events in the accompanying narrative take place. Which of the following statements is true?

____ is when, in modern printing systems, a disk accepts output from several users and acts as a temporary storage area for all output until the printer is ready to accept it.

When the operating system detects a nonrecoverable error, the following step is performed first by the interrupt handler: ____.

____ published a visual tool to show how deadlock conditions can be modeled using directed graphs.

Fill in the missing event that causes deadlock in a database. There are two processes (P1 and P2), each of which needs to update two records (R1 and R2) and the following sequence leads to a deadlock:
1. P1 accesses R1 and locks it.
2. P2 accesses R2 and locks it.
3. ____
4. P2 requests R1, which is locked by P1.

The first and simplest recovery method, and the most drastic, is to ____.

Some systems use a strategy known as ____ to increase the priority of jobs that have been in the system for an unusually long time in order to expedite their exit.

Lock and key synchronization must take place within a single ____.

Each thread in a process is represented by a data structure called a ____ that contains basic information such as the thread’s unique identification, state, and priority.

____ is a dynamic-priority preemptive scheduling algorithm built to address the critical processing requirements of real-time systems and their pressing deadlines.

The Banker’s Algorithm is an example of a(n) ____ policy.

The transition from ____ is initiated by the Job Scheduler according to some predefined policy. At this point, the availability of enough main memory and any requested devices is checked.

A problem with test-and-set is that when many processes are waiting to enter a critical region, ____ can occur because the processes gain access in an arbitrary fashion.

____ is when each process involved in an impasse is waiting for another to voluntarily release its resources so that at least one process will be able to continue.

____ allows for faster turnaround of CPU-bound jobs.

An algorithm designed to detect starvation by tracking how long each job has been waiting for resources is using the concept of ____.

The ____ multiprocessing configuration is the most difficult to implement because the processes must be well synchronized to avoid races and deadlocks.

The ____ multiprocessing configuration features several complete computer systems, each with its own memory, I/O devices, CPU, and operating system.

The Process Scheduler assigns the CPU to execute the processes for those jobs placed on the ____ queue by the Job Scheduler.

An I/O request is called a(n) ____ wait in multiprogramming environments.

The Job Scheduler seeks to ____ when scheduling jobs.

When using the WAIT and SIGNAL operations, ____ sets the process’s process control block to the blocked state and links it to the queue of processes waiting to enter this particular critical region.

Consider the case of a home construction company with two application programs, purchasing (P1) and sales (P2), which are active at the same time. They each need to access two files, inventory (F1) and suppliers (F2), to update daily transactions. The following series of events will cause a deadlock. Fill in the missing event in the sequence.
1. Purchasing (P1) accesses the supplier file (F2).
2. Sales (P2) accesses the inventory file (F1).
3. Purchasing (P1) doesn’t release the supplier file (F2) and requests the inventory file (F1), but P1 is blocked because F1 is being held by P2.
4. Meanwhile, ____

The first-come, first-served (FCFS) algorithm is fine for most ____ systems.

A general rule of thumb for selecting a proper time quantum in Round Robin scheduling is that it should be long enough to allow ____ percent of the CPU cycles to run to completion.

The ____ multiprocessing configuration is an asymmetric system.

Failure to lock database records before updating them may result in a ____ between processes.

Assume that four jobs, A-D, are in the READY queue at Time 0 and require the CPU cycles listed below. Using the SJN algorithm, the ____ job is run first.
Job: A B C D
CPU cycle: 5 2 6 4

In the “dining philosophers” problem, a philosopher can pick up a fork when ____.

When a job is accepted by the system, it’s put on ____ and placed in a queue.

What is the name traditionally given to a semaphore that enforces the concept of mutual exclusion?

In ____ systems, deadlocks can cause critical situations.

____ developed the Banker’s Algorithm.

The scheme of ____ removes the possibility of a circular wait and therefore guarantees the removal of deadlocks.

The transition from ____ can be initiated by the Process Scheduler or the Job Scheduler.

The two operations defined by Dijkstra to be performed on a semaphore are ____.

Fill in the missing event that causes livelock.
At an insurance company, the system performs many daily transactions. One day, the following series of events ties up the system:

1. Process P1 wishes to show a payment, so it issues a command to read the balance, which is stored in cylinder 20 of a disk pack.
2. ____
3. P2 gains control of the I/O channel and issues a command to write someone else’s payment to a record stored in cylinder 310. If the command is not “locked out,” P2 will be put on hold while the control unit moves the arm to cylinder 310.
4. Because P2 is “on hold,” the channel is free to be captured again by P1, which reconfirms its command to “read from cylinder 20.”
5. Since the last command from P2 had forced the arm mechanism to cylinder 310, the disk control unit begins to reposition the arm to cylinder 20 to satisfy P1. The I/O channel would be released because P1 is once again put on hold, so it could be captured by P2, which issues a WRITE command only to discover that the arm mechanism needs to be repositioned.

A(n) ____ is created by a process, and it can be scheduled and executed independently of its parent process.

Assume that four jobs, A-D, require the CPU cycles listed below. Using the SJN algorithm, the average turnaround time is ____.
Job: A B C D
CPU cycle: 5 2 6 4

Which of the following is the first step in reducing a directed graph to eliminate deadlock?

Assume that jobs A-D arrive in the READY queue in quick succession and have the CPU cycle requirements listed below. Using the SRT algorithm, the average turnaround time is ____.
Arrival time: 0 1 2 3
Job: A B C D
CPU cycle: 6 3 1 4

____ is the policy of allowing only one process to have access to a dedicated resource.

____ requires that the processor be allocated to each job or to each process for a period of time and deallocated at an appropriate moment.

A ____ of processing must be handled as a single unit.