Computer Architecture Lecture 05

Computer Architecture

• The design of the internal workings of a computer system, involving decisions about the organization of the hardware, such as the instruction set architecture, data path design, and control unit design.
• Concerned with optimizing the performance of a computer system and ensuring that it can execute instructions quickly and efficiently.

Von Neumann Architecture

• Introduced by John von Neumann in the 1940s as a model for computer architecture.
• Consists of a Central Processing Unit (CPU), memory, and input/output devices.
• The CPU performs tasks such as executing instructions, doing mathematical operations, moving data, and making logical decisions.

Central Processing Unit (CPU)

• The main processor or central processor of the computer.
• Performs tasks such as executing instructions, doing mathematical operations, moving data, and making logical decisions.
• Components of the CPU include:
  • Arithmetic and Logical Unit (ALU)
  • Control Unit (CU)
  • Registers

Instruction Set Architecture (ISA)

• An abstract layer that bridges the communication between computer hardware and software.
• Defines the operations that can be done by the hardware.
• Describes the registers, memory model, behavior of machine code, and data types.
• Examples of ISA include ARM, MIPS, and x86.

Microarchitecture

• The implementation of the Instruction Set Architecture (ISA).
• The ISA acts as the design specification in microarchitecture.
• The microarchitecture design process involves four stages: Fetch, Decode, Execute, and Write Back.

Memory Hierarchy

• The total memory capacity of a computer can be visualized as a hierarchy of components.
• The trade-off between performance and capacity.
• Consists of all storage devices contained in a computer system, from the slowest auxiliary memory to the fastest cache memory.

Memory

• A memory unit is a collection of storage units or devices that store binary information in the form of bits.
• Classified into two categories:
  • Volatile Memory: loses its data when power is switched off.
  • Non-Volatile Memory: permanent storage that does not lose data when power is switched off.

Registers

• A high-speed temporary memory storing unit present in the CPU.
• Can carry any type of information, including a bit sequence or single data.
• The number of bits in a register is called its width.
• Early computers had 8-bit registers, then 16-bit, 32-bit, and today many computers have 64-bit or more registers.

Cache Memory

• The data or contents of the main memory that are used again and again by the CPU are stored in the cache memory.
• The performance of cache memory is measured in terms of the hit ratio.

Main Memory

• Communicates directly with the CPU, auxiliary memory, and cache memory.
• The central storage unit of the computer system.
• Made up of RAM and ROM, with RAM integrated circuit chips holding the major share.

System Bus

• A group of lines that connect the CPU, memory, and I/O devices.
• Meant to carry information.
• Three types of buses: address bus, data bus, and control bus.

Computational Abstraction Layer

• Simplifies the execution of complex programs on large data sets.
• Build complex layers in a bottom-up approach.

I/O Techniques

• I/O devices can not be interfaced to a microprocessor directly.
• Need an I/O interface to communicate with external devices.
• I/O interface contains device selection logic, bus drivers, data buffers, status registers, and control lines.
• Mode of transfer: Programmed I/O, Interrupt-initiated I/O, and Direct Memory Access (DMA).

This quiz covers the fundamental concepts of computer architecture, including Von Neumann architecture, instruction sets, memory hierarchy, system bus, and I/O techniques. It tests your understanding of the internal workings of a computer system.