Solved

Fill in the Missing Event That Causes Livelock

question 20

Multiple Choice

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.

Definitions:

Communicating Acceptance

The act of explicitly or implicitly conveying agreement to the terms of an offer, thereby forming a contract.

Formation of Contract

The process by which parties agree on terms and legally bind themselves to obligations and rights defined by a contract.

Smooth Out Problems

To resolve difficulties or conflicts in a manner that restores normalcy or harmony.

Binding Contract

A legal agreement between parties that is enforceable by law, with specified obligations that must be fulfilled by all involved parties.