Chapter 4(1) + 7(13) OSG
First-come, first-served (FCFS) is a very simple algorithm to implement because it ____. A) uses a FIFO queue B) uses a LIFO queue C) uses a circular queue D) uses a directed graph
A
To put data on an optical disc requires a high-intensity laser beam, which burns indentations, called pits, and flat areas, called ____. A) lands B) valleys C) hills D) lakes
A
____ is a way to optimize search times by ordering the requests once the read/write heads have been positioned. A) Rotational ordering B) SSTF C) C-SCAN D) LOOK and SCAN
A
Data recorded on fixed-head DASDs may or may not be blocked at the discretion of the ____. A) end user B) application programmer C) operator D) database administrator
B
Movable-head magnetic disks, such as the computer hard drive, have ____ read/write head(s). A) zero B) one C) two D) four
B
Some systems increase the priority of jobs that have been in the system for an unusually long time to expedite their exit, which is known as ____. A) lagging B) aging C) bumping D) accelerated priority
B
The data-transfer rate for an optical disc is measured in ____ per second and refers to the speed at which massive amounts of data can be read from the disc. A) kilobytes B) megabytes C) gigabytes D) terabytes
B
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 A) 5.5 B) 6.8 C) 9.0 D) 11.1
C
If the transport speed for a magnetic tape is 200 inches per second and the density is 1600 bpi, a total of ____ bytes can be transferred in one second. A) 3,200 B) 32,000 C) 320,000 D) 3,200,000
C
In a highly interactive environment there is a third layer of the Processor Manager called the ____ scheduler. A) Managing B) Subprocess C) middle-level D) Program
C
The Job Scheduler seeks to ____, when scheduling jobs. A) run all CPU intensive jobs first B) run all I/O intensive jobs first C) balance CPU and I/O intensive jobs D) run the quickest jobs first
C
____ uses the same underlying philosophy as shortest job next, where the shortest jobs are processed first and longer jobs are made to wait. A) LOOK B) FCFS C) SSTF D) SCAN
C
Assume jobs A-D arrive in quick succession in the READY queue. Using round robin scheduling, the turnaround time for job C is ____. Arrival time: 0 1 2 3 Job: A B C D CPU cycle: 8 4 9 5 A) 7 B) 20 C) 22 D) 24
D
The Process Scheduler assigns the CPU to execute the processes of those jobs placed on the ____ queue by the Job Scheduler. A) WAITING B) NEXT C) PROCESS D) READY
D
A fixed-head disk is lower in cost than a movable head disk. A) True B) False
F
An optical disc drive adjusts the speed of the disc's spin to compensate for the sector's location on the disc—this is called continuous linkage velocity (CLV). A) True B) False
F
From HOLD, the job moves to WAITING when it's ready to run but is waiting for the CPU. A) True B) False
F
RAID-0 is ideal for data-critical real-time systems. A) True B) False
F
The Processor Manager is a composite of two submanagers: one in charge of job scheduling and the other in charge of program scheduling. A) True B) False
F
The SCAN algorithm moves the arm methodically from the inner to the outer track, servicing every request in its path. A) True B) False
F
The advantage of RAID Level 3 is that if any one drive fails, data can be restored using the bits in the parity disk. A) True B) False
F
The job of the I/O control unit is to keep up with the I/O requests from the CPU and pass them down the line to the appropriate control unit. A) True B) False
F
Two of the most important measures of optical disc drive performance are sustained data-transfer rate and longest access time. A) True B) False
F
When using DMA, the CPU is involved in transferring data to and from memory for the entire transfer. A) True B) False
F
A DVD with a fast data transfer rate will drop fewer frames when playing back a recorded video segment than will a unit with a slower transfer rate. A) True B) False
T
Additional complex configurations of RAID can be created by combining multiple levels. A) True B) False
T
Among the many differences between an optical disc and a magnetic disk is the design of the disc track and sectors. A) True B) False
T
As a job moves through the system it is always in one of five states (or at least three); these are called the job status or the process status. A) True B) False
T
Direct access storage devices (DASDs) are devices that can directly read or write to a specific place on a disk. A) True B) False
T
Each job is uniquely identified by the user's identification and a pointer connecting it to its descriptor. A) True B) False
T
First-come, first-served (FCFS) is the simplest device-scheduling algorithm. A) True B) False
T
Multiple-level queues isn't really a separate scheduling algorithm but works in conjunction with several other schemes. A) True B) False
T
The traffic controller maintains a database containing the status and connections for each unit in the I/O subsystem, grouped into Channel Control Blocks, Control Unit Control Blocks, and Device Control Blocks. A) True B) False
T
