Exam 5: Process Synchronization

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

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

Although the Banker's Algorithm has been used to avoid deadlocks in systems with a few resources,it isn't practical for most systems.

Resource holding,where a job holds on to one resource while waiting for another one that's not yet available,can be sidestepped by forcing each job to request,at creation time,every resource it will need to run to completion.

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

Database locking should be done only at the level of the entire database.

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

Fixing a deadlock situation requires outside intervention.

In printing systems using ____,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.

In general,operating systems must either choose avoidance or recovery as a strategy for dealing with deadlocks.

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

A livelock can be caused by two processes accessing different areas of the same disk.

A deadlock is preceded by the simultaneous occurrence of six conditions that the operating system (or other systems)could have recognized.

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

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

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,____

Deadlock does not usually affect the entire system.

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.

All recovery algorithms have one feature in common: they all require at least one victim,which,when removed from the deadlock,will free the system.

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.