Computer Organization Chapter 1 Quiz

Questions and Answers

What is the purpose of the instruction register (IR) in the flowchart?

To hold the contents of the memory location being accessed

To store the accumulator content

To manage the program counter

To decode the instruction for execution (correct)

What condition prompts a sequence to execute the instruction 'AC = AC + M(X)'?

If the accumulator AC is less than or equal to 0

If there is an instruction to halt operations

If AC > 0 (correct)

If the memory address X has a value greater than 0

In the flowchart, what does $M(X)$ represent?

The address of the instruction to be executed

The contents of the memory location whose address is X (correct)

The total count of memory cycles used

The next instruction in the program counter

What does the 'PC = PC + 1' operation signify in the flowchart?

It updates the program counter to point to the next instruction Signup and view all the answers

Which of the following correctly describes the action taken when the accumulator (AC) is less than or equal to 0?

The flowchart requests another instruction fetch Signup and view all the answers

What observation did Gordon Moore make regarding transistors on chips?

They were doubling every year. Signup and view all the answers

In the 1970s, the rate of doubling for transistors slowed to what timeframe?

Every 18 months. Signup and view all the answers

Which of the following is a consequence of Moore's Law?

Reduction in cooling requirements. Signup and view all the answers

How has the cost of computer circuitry changed according to Moore's Law?

It has fallen at a dramatic rate. Signup and view all the answers

What impact has Moore’s Law had on the convenience of using computing technology?

Computers are more convenient to use in a variety of environments. Signup and view all the answers

What operation does the opcode 00000101 perform?

Add M(X) to AC Signup and view all the answers

Which instruction would transfer the absolute value of M(X) to the accumulator?

LOAD |M(X)| Signup and view all the answers

What does the opcode 00001100 accomplish?

Divides AC by M(X) and stores the quotient in MQ Signup and view all the answers

Which instruction's opcode is used for transferring the contents of register MQ to the accumulator?

00001010 Signup and view all the answers

What is the function of the opcode 00010011?

Replace right address field at M(X) by 12 rightmost bits of AC Signup and view all the answers

What does the instruction represented by the opcode 00001101 do?

Jump to the instruction in the left half of M(X) Signup and view all the answers

Which opcode allows for a conditional branch to the right half of M(X)?

00001111 Signup and view all the answers

What does the opcode 00010101 perform?

Multiply AC by 2 Signup and view all the answers

Which instruction will transfer M(X) to the accumulator?

LOAD M(X) Signup and view all the answers

The opcode 00001000 is used for which operation?

Subtract |M(X)| from AC Signup and view all the answers

What is the function of the arithmetic-logic unit (ALU) within the CPU?

To perform arithmetic and logical operations Signup and view all the answers

Which register is specifically designed to hold the result of arithmetic operations?

Accumulator register (AC) Signup and view all the answers

What role does the memory address register (MAR) play in the CPU architecture?

It specifies the address of memory to be accessed Signup and view all the answers

Which of the following registers is used to hold instructions fetched from memory?

Instruction buffer register (IBR) Signup and view all the answers

What does computer architecture primarily refer to?

Attributes visible to the programmer Signup and view all the answers

Which term is often used interchangeably with computer architecture?

Instruction set architecture (ISA) Signup and view all the answers

What does the instruction register (IR) do after an instruction is fetched?

Interprets the current instruction for the CPU Signup and view all the answers

Which component of the CPU is responsible for executing sequence control?

Control circuits Signup and view all the answers

What is the purpose of the IBM System/370 architecture?

To allow software upgrades without abandoning original software Signup and view all the answers

The main memory in a CPU is identified by which type of address?

Memory address Signup and view all the answers

Which of the following components is NOT a part of instruction set architecture (ISA)?

Operating system Signup and view all the answers

How does computer organization differ from computer architecture?

Organization involves operational units and their interconnections Signup and view all the answers

What is the purpose of the multiply-quotient register (MQ)?

To store multiplication results and quotient Signup and view all the answers

Which register is responsible for keeping track of the address of the next instruction to be executed?

Program counter (PC) Signup and view all the answers

What is one of the benefits of the IBM System/370 architecture?

It retained the same architecture with technological upgrades Signup and view all the answers

Which circuit is responsible for executing control signals in the CPU?

Program control unit (CC) Signup and view all the answers

Which of the following best describes the function of operational units in computer organization?

To implement the architectural specifications Signup and view all the answers

What was a significant feature of the IBM System/370 that helped protect customer investments?

Backward compatibility with prior models Signup and view all the answers

Study Notes

Computer Organization Overview

Computer architecture highlights system attributes visible to programmers, including instruction set, data type representation, I/O mechanisms, and memory addressing.
Instruction Set Architecture (ISA) encompasses instruction formats, opcodes, and register functions, defining the interaction between software and hardware.
Computer organization focuses on operational units and interconnections that support architectural specifications.

IBM System/370 Architecture

Introduced in 1970, IBM System/370 included multiple models that allowed cost-effective upgrading without software loss.
New models maintained the same architecture, safeguarding customer software investments.
The architecture remains active within IBM's mainframe product line.

Instruction Set and Operations

Symbolic instruction types define how operations are executed, including data transfer, unconditional branch, conditional branch, arithmetic, and address modification.
Key instruction examples:
- LOAD MQ: Transfers contents of register MQ to accumulator AC.
- JUMP M(X): Directs program flow based on conditions.
- ADD M(X): Adds value from memory to AC.

Central Processing Unit (CPU) Components

The CPU includes critical registers:
- AC: Accumulator Register
- MQ: Multiply-Quotient Register
- MBR: Memory Buffer Register
- IBR: Instruction Buffer Register
- PC: Program Counter
- MAR: Memory Address Register
- IR: Instruction Register
Control circuits direct CPU operations via signal outputs.

IAS Structure

The IAS (Instruction Address Space) structure illustrates the relationship between the CPU, memory, and control units during instruction execution.
Data transfer within the IAS includes fetching, decoding, and executing instructions systematically.

Moore's Law

Proposed by Gordon Moore in 1965, it noted that transistor density on chips doubles approximately every 18 months.
This trend has resulted in shrinking computer sizes, decreased power consumption, and enhanced speed.
Dramatic reductions in manufacturing costs of memory and logic circuits have facilitated widespread usage in various applications.

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Description

Test your understanding of the Basic Concepts of Computer Organization and Architecture from Chapter 1. This quiz covers foundational topics essential for mastering computer systems. Brush up on your knowledge and see how well you comprehend the material!