Final Study Guide
Which one of the following statements is true regarding the movement of data in the memory hierarchy?
Data items move down the hierarchy when they are read and up the hierarchy when they are written.
Data items move up the hierarchy when they are read and down the hierarchy when they are written.
Data items move up the hierarchy when they are created and down the hierarchy when they are written.
Data items move down the hierarchy when they are created and up the hierarchy when they are written.
Which one of the following statements is not true of cache memory?
Cache is high-speed temporary storge.
Cache is designed to return answers faster than the mechanism that fulfills a request.
Cache is relatively inexpensive memory.
Cache is positioned between a requestor mechanism and a memory store.
Which one of the following statements best describes the difference between a cache hit and a cache miss?
In a cache hit, the data that has been requested is found in the cache memory and in a cache miss, the data that has been requested is not found in the cache memory.
In a cache hit, the data that has been requested is found in the RAM and in a cache miss, the data that has been requested is not found in the RAM.
In a cache hit, the data that has been requested is found in the ROM and in a cache miss, the data that has been requested is not found in the ROM.
The cost of a cache hit is generally more expensive than the cost of a cache miss.
In the LRU replacement policy, the item to be ejected from cache once cache is full is?
Based on the size of the element needing to be placed in cache.
Based on the priority of the element needing to be placed in cache.
The last item that was placed in the cache.
The item in cache was last referenced the longest time in the past.
Both write through and write back cache techniques place a copy of an item in cache but then how do they differ?
Write through always sends a copy to physical memory and write back only sends a copy to physical memory when necessary.
Write back always sends a copy to physical memory and write through only sends a copy to physical memory when necessary.
Write through always sends a copy to a second cache and write back always sends a copy to physical memory.
Write through always sends a copy to physical memory and write back always sends a copy to a second cache.
There have been three types of cache for some time now, L1, L2, and L3. Historically they have differed based on their placement in a computer. Today they based more on the size of the cache. Which one of the following sequences are listed from the smallest cache to the largest?
L1, L2, L3
L3, L2, L1
L2, L3, L1
L1, L3, L2
A direct mapped memory cache has several of the following characteristics. Which one is not a characteristic?
It divides memory into cache lines which are block that have a size of a power of 2.
A block in cache is known as a cache line.
When a byte is referenced, the entire block that contains the byte is placed in cache.
It contains multiple, independent caches.
Using the formula given in the presentation, what is the relative cache block number of byte address 100?
0
1
2
3
In order to have a cache hit, at least one cache miss must have occurred.
True
False
The hit ratio is the number of hits in a sequence of events that are satisfied by the cache.
True
False
Preloading cache is an optimization technique used to improve cache's overall performance.
True
False
A cache coherence protocol is a set of procedures that are used to prevent problems when two processors share the same cache memory.
True
False
References to instructions are usually random which provides a low locality of reference.
True
False
A block in cache is known as a block line.
True
False
The primary function for most external devices is data transfer.
True
False
Serial data transfer is generally requires more complex hardware than parallel data transfer.
True
False
In parallel data transfer, multiple wires are used to each transmit a single bit at any given time.
True
False
The signals between a processor and an I/O device are called self-checking when the I/O device changes its clock pulse to be synchronized with the processor’s clock pulses.
True
False
A phone conversation is considered a form of full-duplex communication.
True
False
Latency is a measure of time to perform a transfer between a processor and an I/O device and that time is always the same for read operations and write operations.
True
False
Data throughput, also known as speed, is the amount of data that can be transferred per unit of time.
True
False
Data multiplexing refers to the process of separating a stream of data that was created by combining several data sources into one data stream into its individual data streams.
True
False
A processor does not interact directly with an external device, but interacts through a controller for that external device.
True
False
Which one of the following statements is not true about a bus?
A bus is a digital communication mechanism that allows two or more functional units to transfer control signals or data.
A bus defines an address space and establishes the relationship between a bus address space and a memory address space.
Typical use is to connect a processor to a memory or to I/O devices.
A bus consists of a single wire that transfers data and control signals between units.
Which one of the following statements regarding buses is not true?
Most buses are shared by multiple devices.
An access protocol exists that is the rules for how multiple devices use a bus at any given time.
All buses are internal to a processor and located on the processor chip.
It is possible to have multiple buses in one computer.
Which one of the following statements is not a characteristic of a bus?
A bus contains many electronic components.
A bus may support parallel data transfer.
A bus may contain and arbiter that manages the sharing on the bus.
A bus often has sockets into which devices can plug.
What are the three conceptual lines on a bus?
Memory lines, control lines, and data lines
Address lines, control lines, and data lines
Memory lines, address lines, and data lines
Control lines, address lines and memory lines
Bus hardware only supports two operations and that is known as
The read-write paradigm.
The serial-parallel paradigm.
The virtual-physical paradigm.
The fetch-store paradigm.
The width of a bus refers to the
Number of parallel lines contained in the bus.
Physical dimension of the bus.
Amount of data that can be sent over the bus in a unit of time.
Number of control lines contained in the bus.
There are three types of potential bus errors described in the lecture. Which one of the following is not one of them?
An attempt to dereference an invalid pointer.
A processor attempts to reference an address that has not been assigned to any interface.
An address conflict between two devices.
A power outage that disables the bus.
One alternative to a bus is known as switching fabric. Which one of the following statements is not true of a switching fabric alternative?
The major advantage is that it can connect multiple devices simultaneously.
This alternative is a much cheaper cost alternative than a bus.
The sender supplies both the data and destination device.
This alternative is popular for high-performance computer systems.
Which one of the following statements is not true about a device driver?
It is typically part of a computer’s operating system.
Since it contains code that understands hardware details, a high-language is used to code it.
It provides an interface between an application program and an external hardware device.
A device driver interacts with the device over a bus.
Which one of the following parts of a device driver is responsible for handling interrupts?
The lower half.
The shared variables between the upper and lower halves.
The upper half.
The bus to the operating system.
Where is the device driver’s request queue is located?
The lower half.
The shared variables between the upper and lower halves.
The upper half.
The bus to the operating system.
Which one of the following is true?
A device driver resides in the outside of the operating system and run-time library functions that an app uses to perform I/O reside inside the operating system.
A device driver resides inside the operating system and run-time library functions that an app uses to perform I/O resides outside the operating system.
Both a device driver and the run-time library functions that an app uses to perform I/O reside inside the operating system.
Both a device driver and the run-time library functions that an app uses to perform I/O reside outside the operating system.
When an app program or run-time library function invokes an I/O operation, control passes through a system call to a device driver in the operating system causing overhead due to several reasons. Which one of the following is not one of those reasons?
The processor changes the privilege mode because the operating system runs with greater privilege than an app.
The processor must change the address space from the app’s virtual address space to the operating system’s address space.
The processor must copy the data from the app’s address space to the operating system’s address space.
The device driver’s code is interpreted in the operating system while executing.
Which one of the following statements best describes a buffer.
It is an area of memory in which data is accumulated prior to being transferred to an I/O device.
It is a special area in cache that holds data prior to being used by an application program.
It is a special bus that provides faster transfer of data from an I/O device.
It is a portion of a virtual memory table that retains the addresses of all I/O devices.
Assume a user is running an application on a battery powered laptop that displays a progress bar showing how much of an output file has been written. Just as the progress bar reaches 50%, the battery fails and the system crashes. When the user reboots the computer after replacing the battery, he or she discovers that less than 20% of the output file has actually been written. Which one of the following statements explains why has occurred?
Due to a low battery, the progress bar was able to continue working even though the output device was not.
A process bar is stored in cache which is a type of memory that is more resilient than an output device.
The progress bar proceeded as the output was being buffered and the buffers had not yet been flushed when the battery died.
A process bar is stored in the operating system which is the clocked at a faster rate than I/O devices.
To increase the performance of an application, a programmer rewrites the application do that instead of reading one byte at a time, the application reads 8,000 bytes at a time and then processes them. Which one of the following techniques is the programmer using?
Buffering
Interrupt processing
Direct memory access (DMA)
Address configuration
Device transparency means that an application program does not need to change if a device is replaced by a device that provides a similar function.
True
False
A block-oriented device transfers a single byte of data at a time which means an interrupt is generated each time a character is sent or received.
True
False
In queued operations of a device driver, the data is immediately moved from the device into the operating system.
True
False
Device interrupts occur sequentially as in polling.
True
False
The operating system is responsible for providing mutual exclusion in devices drivers.
True
False
The cost of invoking a library function is relatively low since a copy of the code has been included in the app program when it is built.
True
False
Buffer is like caching except that buffering is designed for random access and caching is designed for sequential access.
True
False
When a non-empty buffer is flushed, the data in the buffer is written.
True
False
Which one of the following describes data collected via several sources are transformed into a common format and loaded into a database that users can query?
ELT – Extact, load, and transform
ETL – Extract, transform and load
LET – load, extract, and transform
TLE – transform, load, and extract
Which one of the following statements best describes the difference between synchronous and asynchronous data flow in a data pipeline?
Asynchronous data flow means that a station in the pipeline can forward information at any time and synchronous data flow means that at any given time each station is processing some information.
Synchronous data flow means that a station in the pipeline can forward information at any time and asynchronous data flow means that at any given time each station is waiting to process some information.
Asynchronous data flow means that a station in the pipeline can forward information only for a specified length of time and synchronous data flow means that at any given time each station is waiting to process some information.
Synchronous data flow means that a station in the pipeline can forward information only for a specified length of time and asynchronous data flow means that at any given time each station is processing some information.
A hardware pipeline will only increase throughput if all of the following are true except for which one?
It is possible to partition processing into various stages.
Overhead required to move data from one stage to another is insignificant
It uses processors of the same speed as a nonpipeline architecture
The slowest stage of the pipeline is faster than a single processor
Which one of the following is the term that refers to time required to restart the pipeline after a stage blocks to wait for a previous stage?
Setup time
Sleep time
Flush time
Stall time
Which one of the following is not a factor that controls power consumption?
The fraction of the circuit that is active.
The clock frequency.
The cooling technology used.
The voltage in the circuit.
Which one of the following statements is not considered a characteristic of enter sleep mode on a computer?
The operating system needs to be refreshed every so often.
Save energy.
It is common for embedded processors.
To wake up, a user typically presses a key.
Data pipelining can be implemented as a hardware of software solution.
True
False
A hardware pipeline can help a programmer by decomposing a program into a series of smaller, less complex programs.
True
False
There are three basic types of hardware pipelines, they are instruction pipeline, data pipeline, and bus pipeline.
True
False
Superpipelining refers to a pipeline that has combined several stages in order to improve overall throughput.
True
False
Power is the rate at which energy is generated.
True
False
Switching is a change of a logic gate output when an input changes.
True
False
Only 20 percent of power usage is leakage in a typical computing system.
True
False
Energy is consumed when a clock runs, even if the circuit is not otherwise active.
True
False
Decreasing the clock rate increases the switching power.
True
False
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