04-09-2023
Computer Organization and
Architecture
(Introduction)
Veena Thenkanidiyoor
National Institute of Technology Goa
Structure of a Traditional Computer (Single Processor)
• Central processing unit (CPU)
– Controls the operation of the computer
– Performs the data processing function
– Simply refereed as processor
• Main memory
– Store the data
• I/O
– Move the data between the computer and external environment
• System interconnection
– Mechanism to provide the communication between the functional units
– System bus
• One or more above mentioned components
• Traditionally a single processor
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Contemporary Computers
• Multiple processors
• Terms
- CPU: Portion of the computer that fetches and executes instructions
ALU
Control unit
Registers
On a single processing unit- processor
- Core: An individual processing unit on a processor chip
A processing unit consisting of a control unit, ALU, registers and perhaps
cache
Equivalent in functionality to a CPU on a single-processor system
Sophisticated processing units– specialised for vector and matrix
operations are also referred as cores
- Processor: Physical piece of silicon containing one or more cores
Multicore processor
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Simplified View of a Multicore Computer
• Motherboard
comprises of chips
• Chip is a single piece
of silicon on which
electronic circuits and
logic gates are
fabricated
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Image Source: Computer Architecture and Organization, William Stallings, Pearson
04-09-2023
Simplified View of a Multicore Computer
• Processor chip
contains multiple
cores
• 8 cores
• Shared L3 cache
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Image Source: Computer Architecture and Organization, William Stallings, Pearson
Simplified View of a Multicore Computer
• Functional elements of a core
– Instruction logic
Fetching and decoding
– Arithmetic and logic unit
– Load/store logic
– L1 cache
Instruction and data
– L2 cache
Instruction and data
Image Source: Computer Architecture and Organization, 6
William Stallings, Pearson
04-09-2023
History of Computers
• First generation
- Vacuum tubes for digital logic elements and memory
- Second generation
- Transistors replaced vacuum tubes
- Smaller, cheaper and generates less heat
- Provision of system software
- Third generation
- Integrated circuits
- Microelectronics
Reduction in the size of digital electronic circuits
Small scale integration (SSI): A few gates or memory cells packaged together
Later Generations
• Less general agreement on defining generations of computers
- There have been a number of generations
• Advancement in hardware technology
- More than 10000 components per chip
Large scale integration (LSI)
Very large scale integration (VLSI)
- Ultra large scale integration: More than one billion components
- Semiconductor memory—development in memory technology
Earlier magnetic memory
- Microprocessors—density of processor chips increased
First microprocessor-Intel 4004– Contain all components of a CPU on a single
chip
Number of bits that can be handled (4, 8, 16 and so on)
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Later Generations
• Intel x86 architecture
- Complex instruction set computer (CISC)
- Stands number one in the market share of non-embedded
systems
• ARM architecture
• Reduced Instruction set computer (RISC)
• Embedded systems
Embedded Systems
• Use of electronics and software within a product
- As opposed to general-purpose computer such as laptop or desktop computer
• Millions of computers sold every year-laptops, personal computers,
workstations, servers, mainframes and supercomputers
• Billions of computer systems that are embedded within larger
devices
- Cell phones, digital cameras, video cameras, calculators, microwave ovens,
home security systems, washing machine ….
• Internet of things (IoT)
- Major drivers in the proliferation of embedded systems
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Computer Organization and Architecture
• Computer Architecture
– Aspects that have direct impact on the logical execution of a program
– Also called as Instruction Set Architecture (ISA): instruction formats,
instruction opcodes, registers, memory
ADD instruction: A programmer is allowed to use
MUL instruction
• Computer Organization
– Operational units and their interconnections to realise the architectural
specifications
How the ADD operation should be internally realised?
o Transparent to the programmer
Whether MUL instruction will be implemented by a special multiply unit or by
repeated use of ADD instruction
o Decision based on anticipated frequency of use of an instruction, relative speed of the
approaches cost and physical size of an a special multiply unit
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Computer Organization and Architecture
• Many computer manufactures provide an architecture that may span
many years
– Many models that may follow the same architecture but different organization
– Different models have different price and performance characteristics
• Course focus:
– Organization and Architecture both
• Single processor computer
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04-09-2023
Digital Computer
• Computer is a fast electronic computing/calculating machine that
– Accepts digitized input information
– Processes it according to a list of internally stored instructions
– Produces the resulting output information
• Internal storage is called computer memory
• List of instructions is called a computer program
• Many types of computers exists that differ widely in size, cost,
computational power and purpose of use
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Computer Types
• Personal computer ---common form of desktop computer
– Processing and storage units, visual display and audio output units and a
keyboard
• Notebook computers
– Portable compact version of the personal computer with all its components
packed into a single unit
• Workstations
– High-resolution graphics input/output capability, dimensions of a desktop
computers
– Significantly more computation power than personal computers
• Enterprise systems-mainframes
– For business data processing in medium to large corporations
– More computation power and storage capacity than workstations can provide
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Computer Types
• Servers
– Sizeable data storage units and are capable of handling large volumes of
requests to access the data
– Education, business …
– Remote request over Internet
– Internet servers
• Supercomputers
– For large scale numerical calculations
Weather forecasting, aircraft simulation
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Thank You
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