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.