OS Quiz 7
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.
320,000
Data recorded on DASDs may or may not be blocked at the discretion of the ____.
Application Programmer
Without DMA, the ____ is responsible for the physical movement of data between main memory and the device.
CPU
The number of characters that can be recorded per inch on a magnetic tape is determined by the ____ of the tape.
Density
T/F A find strategy determines the order in which the processes get the I/O handler device, and the goal is to keep seek time to a minimum.
False
T/F A fixed-head disk is lower in cost than a movable head disk.
False
T/F On a magnetic tape, the inter-record gap (IRG) is about two inches long regardless of the sizes of the records it separates.
False
T/F The SCAN algorithm moves the arm methodically from the inner to the outer track, servicing every request in its path.
False
T/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.
False
T/F The traffic controller maintains a spreadsheet file 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.
False
T/F Two of the most important measures of optical disc drive performance are sustained data-transfer rate and longest access time.
False
T/F When using DMA, the CPU is involved in transferring data to and from memory for the entire transfer.
False
The USB controller assigns bandwidth to each device depending on its priority, and the ____ priority is assigned to real-time exchanges where no interruption in the data flow is allowed, such as video or sound data.
Highest
On an optical disc, all sectors are ____.
Of the Same Size Throughout the Disc
Movable-head magnetic disks, such as the computer hard drive, have ____ read/write head(s).
One
The I/O ____ allocates the devices, control units, and channels.
Scheduler
Of the three components of access time in a movable-head DASDs, ____ is the longest.
Seek Time
____ bits make up the Channel Status Word (CSW) flag.
Three
In a fixed-head magnetic disk, each circle is called a ____.
Track
T/F A magneto-optical (MO) disk drive combines the technology of magnetic disks with that of optical discs.
True
T/F Among the many differences between an optical disc and a magnetic disk is the design of the disc track and sectors.
True
T/F Buffers are used extensively to better synchronize the movement of data between the relatively slow I/O devices and the very fast CPU.
True
T/F DASDs are good for files with low activity (the percent of records accessed) or for users who access records in a random fashion.
True
T/F Direct access storage devices (DASDs) are devices that can directly read or write to a specific place on a disk.
True
T/F Each unit in the I/O subsystem can finish its operation independently from the others.
True
T/F First-come, first-served (FCFS) is the simplest device-scheduling algorithm.
True
T/F N-Step SCAN holds all new requests until the arm starts on its way back.
True
T/F The universal serial bus (USB) controller acts as an interface between the operating system, device drivers, and applications and the devices that are attached via the USB host.
True
