This is a quick overview on the hardware computer architecture. Slides can be used as an introductory session to programming classes or computer architecture courses.

1. Introduction to Hardware
Computer Architecture
Abd El-Rahman Hosny Mohammed
Microsoft Student Partner.
4th Grade – Faculty of Computers and Information.
Computer Science Department.
Assiut University.
contact: abdelrahmanhosny.com

2. Agenda
- Life Before the Digital World.
- Logical Circuits.
- Integrated Circuits (ICs).
- Computer Hardware Components.
- Instruction Set Architecture level.
- Operating System Level.
- Higher-Order Language Level.
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3. Life Before the Digital World
- The word “computer” was called to anybody or anything that carry out
calculations and computations.
- At late 19ths, the a “computer” was familiarized to any machine that
carries out calculations.
- Mechanical machines were developed to carry out calculations and
some fixed functions (not programmable).
- Programmability was introduced by the invention of “punched cards”.
- Mechanical computers could recognize the punched cards patterns.
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4. - Punched cards as well as tapes were used to record data.
- This improvement was the foundation od modern information
processing industry.
- Scientific computing needs were met by analog and mechanical
computers. But they were inaccurate and not-programmable.
- Alan Turing conceptualizes the concept of computing in the “Turing
Machine”.
- A device that manipulates symbols on a strip of tape according to a
table of rules.
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5. Turing Test
- It’s the ability of a computer to exhibit intelligent behavior.
- If we could make a computer-human conversation that is
indistinguishable from a human-human conversation, a machine is said
to have passed the test.
- Till now, no machine has passed the Turing test !!
- Now, the world is moving toward building a smart machine that acts
intelligently to human.
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6. Logical Circuits
- With the invention of capacitors, the world began to become digital.
- The first computers were made up of tubes. They were really big in a
size of a room !!
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7. - Discovering semiconductors was a great achievement that kicked-off
the computer world to what we can see today.
- Capacitors and transistors became very small.
- These components used for storing data as digital
signals.
- Digital signals are binary signals that represent
a 1 as a high-volt (5 v.) and a 0 as a low-volt (0 v.).
- A computer can store any data in the form of
a stream of 0s and 1s.
- So, binary encoding is used to convert any
decimal number into a binary one.
For Example: 75 is represented as 01001011.
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8. Integrated Circuits
- We collect these small components in small chips which are called
Integrated Circuits.
- Small-Scale Integration (SSI): up to 100 electronic component per chip.
- Medium-Scale Integration (MSI): from 100 to 3,000 electronic
component per chip.
- Large-Scale Integration (LSI): from 3,000 to 100,000 electronic
component per chip.
- Ultra Large-Scale Integration (ULSI): more than 1 million electronic
component per circuit.
- These integrated circuits (ICs) are the components
of modern and future computers.
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9. Computer Hardware
- Computer hardware are the physical parts that constitutes the machine.
- Through years, hardware architecture has evolved.
- The most common hardware architecture is the Von Neumann model.
- Let’s investigate each part.
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CPUInput Output
Memory

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CPUInput Output
Memory
- Keyboard (standard input).
- Mouse.
- Scanner.
- Web Cams.
- Touch Screen.
- Laser Pen.
:
:
And so on.
- Screen (standard output).
- Printers.
- Speakers.
:
:
And so on.
Drivers
These are the hardware
interfaces between
external devices and
the CPU.

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CPUInput
Memory
Output
Memory is the RAM used for program
code as well as data.
- Address Bus -
- Data Bus -
- Control Bus -

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CPUInput
Memory
Output
ALU
registersArithmetic & Logic Unit
- ALU is the heart of the computer. It’s responsible
for doing computations
(Add, Subtract, Multiply, …etc.).
- ALU can do these computations ONLY on the
values in the registers.
- Registers are much like memory locations
(Address-Value pairs), but have less access time.

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Instruction Set Architecture Level
- Companies that manufacture CPUs must accompany it with the
instruction set that the ALU can perform.
- Instructions are assembly language keywords that perform a specific
action. For example, add two numbers.
- Let’s see an example:

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Operating System Level
- The operating system is the KING of the computer kingdom.
- It’s a software level that manage the different hardware resources
using the instructions provided by the manufacturer of every device.
- It has too many functionalities, some of them are:
- Usually operating systems are developed using C/C++ and assembly
programming languages.
 Program Execution
 IO operations
 File-System Manipulation.
 Communications.
 Error Detection.
 Security.

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Higher-Order Language Level.
- There are many high-level language that make the programming
task easier for developers.
- Examples: C++, Java, C#, …etc.
Why there are too many programming
languages ?
Why there are new emerging languages ?
But …

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- Introduction to Computer Science.
- Introduction to Computer Programming.
- Programming Languages.