CH01

Chapter 1: Introduction to Computer Organization and Architecture

1.1 Objectives

• Distinction between computer organization and architecture

• Familiarity with units of measure common in computer systems

• Understanding the evolution of computers

• Concept of the computer as a layered system

• Explanation of the von Neumann architecture and basic components of computers

1.2 Overview of Computer Organization and Architecture

• Purpose of Studying:

  • Designing better software (e.g., system software, compilers, operating systems)

  • Optimizing program behavior

  • Evaluating computer system performance (benchmarking)

  • Understanding trade-offs among time, space, and costs.

• Computer Organization:

  • Covers physical aspects (circuit design, control signals, memory types).

• Computer Architecture:

  • Involves logical aspects from a programmer's viewpoint (instruction sets, formats, data types, addressing modes).

1.3 Basics of Computer Systems

• There is often no clear boundary between organization and architecture.

• Principle of Equivalence of Hardware and Software:

  • Any software task can be performed with hardware, assuming no speed limits.

• Essential Components of a Computer:

  • Processor: interprets and executes programs

  • Memory: stores data and programs

  • I/O mechanism: interacts with the external environment.

1.4 Measuring Capacity and Speed

• Units of Capacity:

  • Kilo (K) = 1e3 and 2^10

  • Mega (M) = 1e6 and 2^20

  • Giga (G) = 1e9 and 2^30

  • Tera (T) = 1e12 and 2^40

  • Peta (P) = 1e15 and 2^50

  • Exa (E) = 1e18 and 2^60

  • Zetta (Z) = 1e21 and 2^70

  • Yotta (Y) = 1e24 and 2^80

  • The type of measure depends on context (bytes vs bits).

• Frequency Measurement: Hertz (Hz) indicates clock cycles per second. Examples: 1MHz = 1e6 Hz, Processor speeds in MHz/GHz.

• Storage Units:

  • Byte = 8 bits

  • Storage measured in KB (10^3/2^10 Bytes), MB, GB, TB based on system size.

1.5 Temporal and Spatial Measures

• Time Measurements:

  • Milli (m), Micro (µ), Nano (n), Pico (p), Femto (f), Atto (a), Zepto (z), Yocto (y) - representing fractions of seconds for various computing speeds.

• Example Access Times:

  • HDD: 10-20 ms

  • Memory: 50-70 ns

  • Circuit dimensions: measured in microns.

• Cycle Time Calculation:

  • E.g., a bus operating at 133 MHz has a cycle time of ~7.52 ns.

1.6 Example Computer System

• Components:

  • Intel i9 Processor at 4.2 GHz - ‘brain’ of the system.

  • RAM and Cache: 32GB DDR4 SDRAM with L1 and L2 cache levels.

  • Dual storage setups with HDD and SSD (7200 RPM HDD, 128GB SSD).

  • Various I/O interfaces including USB ports, PCI slots, HDMI.

  • Monitor specifications (1920 x 1200 resolution, active matrix technology).

1.8 Standards and Organizations

• Importance of establishing hardware standards:

  • IEEE: Sets standards for computer components and protocols.

  • ITU: Focuses on telecom interoperability.

  • ANSI and BSI: National standards organizations.

  • ISO: Worldwide standards for all types of manufacturing including IT.

1.9 Historical Development of Computers

• Generations of Computers:

  • Zero: Mechanical Calculators (1642-1945).

  • First: Vacuum Tube Computers (1945-1953).

  • Second: Transistorized Computers (1954-1965).

  • Third: IC Computers (1965-1980).

  • Fourth: VLSI Computers (1980 onwards).

  • Moore’s Law: Density of transistors doubles approximately every 18 months.

1.10 The Computer Level Hierarchy

• Layered architecture of computers:

  • Level 0: Digital Logic

  • Level 1: Control

  • Level 2: Machine

  • Level 3: System Software

  • Level 4: Assembly Language

  • Level 5: High-Level Language

  • Level 6: User Level

  • Whenever one level makes a call, it relies on the functions upheld by the layer beneath.

1.11 Cloud Computing

• Concept of computing as a service has evolved with cloud models like SaaS, PaaS, and IaaS.

• Features include elasticity means resources scale according to demand and virtualization allowing multiple logical machines on physical hardware.

Conclusion

• This chapter provides foundational insight into computer architecture, paving the way for more intricate study in forthcoming chapters.