57)
The system bus consists of all of the following except ________.
57)
A)
control bus
B)
power bus
C)
data bus
D)
address bus
58)
System software ________.
58)
A)
manages all the hardware and software in a system
B)
is also called application software
C)
is stored in main memory
D)
accomplishes a specific job or task
59)
When running a program a processor repeatedly executes a cycle that contains ________.
59)
A)
a data write–back phase
B)
an instruction decode phase
C)
a fetch phase
D)
none of the above
60)
The instructions contained in ROM as part of a computer’s own operating instructions are referred
to as ________.
60)
A)
firmware
B)
assembly language instructions
C)
BASIC interpreter instructions
D)
machine language code
61)
What is polled I/O and what is its major characteristic?
61)
A)
Individual I/O devices regularly send inquiries to the CPU to see if it is available for a specific
I/O operation; if the CPU is available, the I/O device then proceeds to carry out its operation.
B)
Each individual I/O device is checked sequentially on a regular basis to see if it needs to be
serviced. This slows down the CPU operation.
C)
Each individual I/O device is checked sequentially on a regular basis to see if it needs to be
serviced. This speeds up the I/O process.
D)
Each individual I/O device is serviced sequentially on a regular basis. This speeds up the I/O
process.
62)
Direct memory access is ________.
62)
A)
faster because it substitutes higher speed static RAM for slower dynamic RAM (DRAM),
which has to be refreshed on a regular basis and thus slows down the entire computer system
B)
handled by a special DMA controller and is usually several times faster than data transfers
handled by the CPU
C)
faster than ordinary memory access techniques because it allows each I/O device direct access
to the CPU memory
D)
any one of the above, depending on the particular computer system
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
63)
During a write operation the processor places an address on the address bus and data on the data
bus, and the device generates a write signal to indicate it has stored the data.
63)
64)
Cache memory is used to overcome the relatively high costs of main memory.
64)
65)
Bus master use interrupts to gain control of the system bus from the CPU.
65)
66)
Processors typically use only one addressing mode to standardize how data is stored and accessed
in a system.
66)
67)
Instructions are decoded during the fetch phase of an processor cycle.
67)
68)
The address register generates the sequence of memory addresses from which program instructions
are taken.
68)
69)
Microcontrollers are a type of general purpose processor.
69)
70)
The addresses of the routines that handle interrupts and exceptions are stored in a special region of
memory called the stack.
70)
71)
Computer systems use buffers to decrease the propagation delay of system buses.
71)
72)
Buffers are used to ensure that the power dissipation of a device driving multiple loads is not
exceeded.
72)
73)
The interrupt–driven I/O scheme overcomes the problems associated with polled I/O by
communicating with the CPU through the address bus.
73)
74)
Pipelining is a means of increasing the bus speed of a processor.
74)
75)
Microcontrollers use ADCs and DACs to interact with the analog world.
75)
76)
One of the basic functional blocks of a microcomputer is the arithmetic logic unit.
76)
77)
When the fanout of a device is exceeded the device may not meet its output voltage or timing
specifications.
77)
78)
Microcontrollers are most often used to build systems that will run application software.
78)
79)
Special subroutine that contains instructions to process interrupts and exceptions are called
programmable interrupt controllers.
79)
80)
Microcontroller peripherals typically require control registers to specify how the peripheral will
function.
80)
81)
GPIO stands for general purpose I/O.
81)
82)
A system device that handles many details of memory operation in a computer system is the DMA
controller.
82)
83)
Logic devices whose outputs must share signal lines with the outputs of other devices must have
tri–state of open collector outputs to avoid bus contention.
83)
84)
The difference between exceptions and interrupts are that exceptions are generated by hardware
and interrupts are generated by software.
84)
85)
Processors must automatically store the contents of the condition code register on the stack when
responding to an interrupt or exception.
85)
86)
One function of the control bus is to control the speed at which the processor operates.
86)
87)
In some computer systems only the CPU is a bus master.
87)
88)
Content addressable memory is also called associative memory.
88)
89)
Wait states are used to ensure that processor signals meet the setup and hold times of system
devices.
89)
90)
Microcontrollers use data registers to contain information about conditions associated with
peripheral operation.
90)
91)
Another name for the condition code register is the instruction decode register.
91)
92)
To ensure that processors can specify which device in the system they wish to access, digital
devices like memory have a chip select or chip enable input.
92)
93)
Operands are always one–byte values.
93)
94)
A bus master is any device in the computer system that can control the system buses.
94)
95)
General purpose processors typically have control lines with which to select system devices.
95)
96)
Interfaces that allow computers to transfer data to and from external devices are called data buffers.
96)
97)
Multitasking operating systems requires hardware support from the CPU.
97)
98)
Multitasking allows a single processor to run more than one process.
98)
99)
When a program is running, the processor goes through a fetch/execute cycle.
99)
100)
Polled I/O operation is periodic, inefficient, and generally allows no priority assignments.
100)
101)
One role of the operating system is to schedule and allocate system resources.
101)
102)
One important class of bus master is the DMA (direct memory access) controller.
102)
103)
Processors have supervisor and user states to ensure that only certain processes in multiuser or
multitasking systems have access to restricted system resources.
103)
104)
Microcontroller systems that track moving objects require two quadrature encoders for each axis of
motion.
104)
105)
Encoders can be used to generate wait state signals.
105)
106)
Word processors and spreadsheet programs are examples of application software.
106)
107)
One addressing mode that requires an additional register to generate the operand address is
indexed addressing.
107)
108)
Two events than can cause the processor to deviate from its normal operation are exceptions and
interrupts.
108)
109)
BIOS memory holds system–specific low–level code.
109)
110)
Processor registers consist of general purpose registers to store data the processor may require and
special registers that perform special functions within the processor.
110)
111)
System software is called the operating system.
111)
112)
One role of the CPU is to coordinate the operation of devices in the computer system.
112)
113)
The object manipulated by a processor instruction is called the operand.
113)
114)
The width of the address bus determines how many locations the microprocessor can directly
access.
114)
115)
Pulse width modulators are often used for motor control in microcontroller systems.
115)
116)
The address bus, along with the data and control busses, is bidirectional.
116)
117)
During a read operation the processor places an address on the address bus, generates a read
signal, and waits for the selected device to place data on the data bus.
117)
118)
Immediate addressing implicitly contains the operand address in the opcode.
118)
119)
Microcontroller designs must typically include additional system devices like external memory,
memory controllers, and communication controllers.
119)
120)
DMA allows the CPU to process data transfers between RAM and I/O devices faster by speeding
up the CPU clock during operations that do not require the use of the ALU.
120)
121)
Synchronous buses uses a clocking signal to ensure that signal meet setup and hold times but are
slower than asynchronous buses.
121)
122)
Memory–mapped I/O and direct I/O differ in that memory–mapped I/O stores data in memory
before transferring it in or out of the computer.
122)
123)
One drawback of buffers is that they increase the propagation delay of signals passing through
them.
123)
124)
One type of system service provided by a multitasking operating system is passing messages
between system processes.
124)
125)
The two classes of devices that computer systems use to hold information are memory devices and
storage devices.
125)
126)
Control buses differ from other system buses in that control bus signals are unidirectional.
126)
127)
The control bus and memories share a bidirectional relationship in a typical microcomputer
system.
127)
128)
Memory and other peripheral devices typically have a signal that lets the processor know when
data is ready.
128)
Answer Key
Testname: C14
Answer Key
Testname: C14
Answer Key
Testname: C14