Computer Organization Chapter 8: Input/Output

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Questions and Answers

What is the primary advantage of DMA in the evolution of I/O functions?

It allows CPU to completely bypass the I/O process.

It allows all data transfers to occur without any need for interrupts.

It transforms the I/O module into a CPU, eliminating the need for a main CPU.

It enables the I/O module to access memory directly without CPU intervention. (correct)

At which step in the evolution of I/O functions does the CPU begin to utilize programmed I/O?

Step 3

Step 2 (correct)

Step 1

Step 4

What enhancement is made to the I/O module in Step 5 of the evolution of I/O functions?

The I/O module is given access to a shared memory with the CPU.

The I/O module is eliminated in favor of direct memory control by the CPU.

The I/O module is modified to handle interrupts more effectively.

The I/O module is developed to act as a processor with tailored instructions. (correct)

Which step in the I/O function evolution allows for minimal CPU involvement in controlling I/O devices?

Step 6 Signup and view all the answers

What role does the I/O module play in the configuration described in Step 4?

It allows for block data movement to and from memory with limited CPU involvement. Signup and view all the answers

What is the first step that occurs when a packet arrives?

DMA Signup and view all the answers

Which process occurs after the NIC interrupts the host?

Output operation invoked Signup and view all the answers

What is the purpose of the DCA function in the memory controller?

To provide a prefetch hint to the core Signup and view all the answers

Which I/O technique allows the processor to execute other instructions while waiting for an operation to complete?

Interrupt-driven I/O Signup and view all the answers

What benefit does avoiding the system buffer in main memory provide?

Improves packet retrieval speed Signup and view all the answers

What type of command is used to activate a peripheral and instruct it on what to do?

Control command Signup and view all the answers

Which I/O method can lead to inefficient use of processor time if the processor is faster than the I/O module?

Programmed I/O Signup and view all the answers

What does the core do with the packet descriptor information when a packet is received?

Reads it directly from the buffer Signup and view all the answers

In which processor line was the Direct Data I/O implemented?

Intel Xeon Signup and view all the answers

In which I/O technique does the I/O module and main memory exchange data directly, without processor involvement?

Direct Memory Access (DMA) Signup and view all the answers

What is the primary function of the Read command in I/O operations?

To obtain data from a peripheral Signup and view all the answers

What occurs after a cache miss during packet processing?

Header is processed Signup and view all the answers

How does cache injection facilitate packet processing?

By allowing core to bypass main memory Signup and view all the answers

Which I/O technique is most efficient when multiple peripherals are involved and can function independently of the processor?

Direct Memory Access (DMA) Signup and view all the answers

Which command allows the I/O module to test various status conditions associated with its peripherals?

Test command Signup and view all the answers

Which of the following techniques is characterized by the processor being directly involved in every I/O operation?

Programmed I/O Signup and view all the answers

What is the key difference between memory-mapped I/O and isolated I/O?

Memory-mapped I/O allows direct access to I/O devices through memory instructions, while isolated I/O requires special commands. Signup and view all the answers

Which instruction is used to initiate a keyboard read in the memory-mapped I/O example?

Store AC Signup and view all the answers

What happens when a processor is using interrupt-driven I/O?

The processor can perform other tasks until interrupted by the I/O module. Signup and view all the answers

In the context of programmed I/O, what is a major disadvantage?

It leads to processor idle time while waiting for I/O operations. Signup and view all the answers

Which of the following indicates the status of the keyboard input in the memory-mapped I/O?

The Keyboard input status and control register at address 517. Signup and view all the answers

What is the purpose of the instruction 'Branch Not Ready' in isolated I/O?

To continue checking if the I/O operation is complete. Signup and view all the answers

What does the status bit in the keyboard input status register signify when it is set to 1?

The keyboard input data is ready to be read. Signup and view all the answers

Which part of the interrupt-driven I/O process involves the processor resuming its previous tasks?

Executing data transfer. Signup and view all the answers

What is the binary representation of the decimal number -3 in a 4-bit system?

1011 Signup and view all the answers

In an n-bit two's complement representation, what is the range of integers that can be represented?

$-2^{n-1}$ to $2^{n-1} - 1$ Signup and view all the answers

What is the two's complement of the binary number 0110?

1010 Signup and view all the answers

Which binary number represents the decimal value +4 in a 4-bit two's complement format?

0100 Signup and view all the answers

What will be the result of adding the binary numbers 0111 and 0001 in a 4-bit system?

1000 Signup and view all the answers

In the geometric depiction of two's complement integers, what does '1110' represent?

-3 Signup and view all the answers

What is the effect of applying two's complement to a negative binary number?

It converts it to a positive number. Signup and view all the answers

For a 4-bit system, what is the binary representation of the decimal number -5?

1001 Signup and view all the answers

What is the first step when performing floating-point multiplication if both inputs X and Y are zero?

Return zero Signup and view all the answers

What occurs after normalizing the result in floating-point multiplication?

Subtract bias from the exponent Signup and view all the answers

In floating-point addition or subtraction, what condition leads to underflow when checking the significand?

The significand is equal to zero Signup and view all the answers

What should be reported if the exponent after a floating-point operation exceeds its limits?

Overflow Signup and view all the answers

In the context of floating-point operations, what is done just before returning the final result?

Round off the significand Signup and view all the answers

What happens if the significand is found to be zero during floating-point subtraction?

Zero is returned immediately Signup and view all the answers

During floating-point operations, when is it necessary to subtract the bias from the exponent?

Where the exponent is adjusted Signup and view all the answers

What is the primary condition to check first when performing floating-point multiplication?

If either X or Y equals zero Signup and view all the answers

Study Notes

Computer Organization and Architecture

The book is titled "Computer Organization and Architecture Designing for Performance" 11th Edition, Global Edition
It is published by Pearson

Chapter 8: Input/Output

I/O modules link external devices to the computer system.
A generic I/O module interfaces with the system bus and peripheral devices.
External devices can be categorized as human-readable (VDTs, printers) and machine-readable (magnetic disks, sensors).
There are links to peripheral devices present in I/O module
There are specific external devices such as video display terminals, printers, magnetic disk and tape systems, sensors, and actuators, that can be categorized as human readable.
Key I/O functionalities include control and timing, processor communication and device communication.
I/O operations can be handled using programmed I/O, interrupt-driven I/O, or DMA.
A block diagram shows the internal components of an external device, including control logic, a buffer, and a transducer.
Input/output commands involve control, test, read and write signals to the peripherals.
Common I/O mechanisms (table) include programmed I/O, interrupts, and DMA.
I/O instructions include commands, such as control, test, read, and write.
Three common I/O techniques are programmed I/O, interrupt-driven I/O, and direct memory access (DMA).
Memory-mapped I/O and isolated I/O are two different approaches to addressing I/O devices.
Keyboard/monitor input/output uses the International Reference Alphabet (IRA) code.
Devices are identified differently with multiple interrupt lines, software poll, daisy chain, or bus arbitration schemes.

Chapter 10: Number Systems

The text defines the decimal system as a positional number system based on the digits 0-9.
Decimal fractions utilize negative powers of 10 for fractional parts.
The general form for these systems is (...a3a2a1a0.a_1a_2a_3...)r.
A number in a positional number system has weights associated with each digit position, determined by the radix (or base) raised to the power of the position.
The binary system, based on 0 and 1, uses powers of 2 to represent numbers.
The hexadecimal system uses the sixteen symbols 0-9 and A-F to represent numbers.

Chapter 11: Computer Arithmetic

An Arithmetic Logic Unit (ALU) performs arithmetic and logical operations on data.
The ALU is the core computational component of a computer, receiving and sending data to it via operands and results.
Integer representation methods include sign-magnitude, twos complement, and biased representation.
Range extension methodologies apply to integer representation, extending the representable range by increasing the bit length.
This is done by shifting the sign bit to the leftmost position and filling remaining bits with the sign bit.
Fixed-point representation has a fixed position for the radix point.
Floating-point representation uses a different representation for fractions to allow them to be represented in the system.
IEEE 754 standards define different types of floating-point formats.
Interval arithmetic can represent a range of values, useful for error control, by representing the result as a range of values, one lower and one upper bound.
Truncation is a type of rounding toward zero
Infinity is a concept used to deal with results of operations like division by zero, where the result is treated as a large value beyond the range of representable numbers.
Overflow and underflow are conditions that may occur during arithmetic operations in twos complement and floating-point representations.
A guard bit can be used to store bits when the precision of a result is limited by the size of a register.
The IEEE standard for binary floating-point arithmetic handles cases like infinity and NaN (Not a Number).
Other methods for performing operations such as multiplication, division, and exponentiation.

Chapter 13: Instruction Sets: Characteristics and Functions

A machine instruction specifies the operation executed by the computer. The instruction set is the collection of all instructions executed by the processor.
Instructions include opcodes, operands, and addresses. Operands are the data the instruction operates on, and can be in memory, registers, or immediate values.
Instructions can include a sequence of operations.
Various data types are present in computers for different purposes such as numbers, characters, and logical data.
Processors use an instruction set.
Data types include integers, packed decimal, Floating-Point, and decimal.
A simple instruction is a sequence of bits corresponding to opcodes and operands.
Different types of operations exist in instructions, including data transfer, arithmetic, logical, conversion, input/output, and transfer of control.
Instruction set design involves various key issues: operation repertoire, data types, instruction format, registers, addressing.
Examples of instructions and their operations provided in table format.

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Description

Explore the critical functions of Input/Output modules in computer systems with this quiz. Learn how I/O devices interface with the system bus and the different categories of external devices. Test your understanding of I/O operations, including programmed I/O, interrupt-driven I/O, and DMA.