The document provides a history of computers from early counting aids to modern personal computers. It describes the development of binary numbering systems and components of early computers like the Analytical Engine, ENIAC, and UNIVAC. It also discusses basic computer concepts like data storage, processing units, algorithms, programming, and hardware/software components.

1. FOUNDATIONS OF
ENGINEERING

2. CHAPTER # 4
Understanding and Using Computers

3. A BRIEF HISTORY OF COMPUTERS
Our finger formed the first aid to counting
Roughly 3000 -> aid for merchant & government officials for tracking money
Around 2000 years ago -> Hero’s odometer -> counting
In the early 1600s, John Napier develops the theory of logarithmic
In 1622, William Oughtred improves Napier’s bones by developing the slide
rules
In 1642, Blaise Pascal created an adding/subtracting device similar to
odometer
In 1671, Gottfried Leibniz -> created mechanical device -> for
multiplication/division and also do addition/subtraction. He was the first to
recognize the importance of binary numbering system

4. Around 1842, Charles Babbage devised the Analytical Engine, a machine that
had all the properties of present day computers. It could follow a set of
instruction stored on punched cards, it could calculate and stored numbers
In 1890, punched car machine constructed by Herman Hollerith and James
Powers were used to tabulate census data. The holes were punched by hand
and the card was placed upon a pool of memory.
In the late 1930s, John Atanasoff and Clifford Berry built an electronic digital
computer using capacitor & vacuum tubes to store and manipulate binary
numbers using logic rather than counting
In 1944, Howard Aiken completed the Harvard mark I, an electrically driven
mechanically computer that was jointly developed by IBM & Harvard University.
It used punched paper tape to find instruction and data. Capable of performing
mathematical operation in a controlled sequence. Considered as a 1st
information-processing machine.

5. For the war effort, J. Presper Eckert & John W. Mauchly developed ENIAC
Computer to calculate artillery firing tables that list trajectories for the angles
of fire, muzzle velocities and so forth. It used a computer architecture
developed by John von Neuman and contained 18000 vacuum tubes and 1500
relays, weighed 30 tons, was two stories high and required 15000 square feet.
It could multiply two digit 10-digit numbers in 0.003s, compared to 3s
required by the Harvard.
In 1948, IBM introduced a commercial electronic calculator called 604 that
used punched card
 In 1951, a company founded by Eckert & Mauchly introduced the Univac. It
was the 1st commercial computer capable of running stored programs.
By 1954, there was many computer available on the market.
That year saw the introduction of the FORTRAN computer language,
developed by John Bakus of IBM

6. By 1958, Computer designers completely replaced vacuum tubes with
transistors, thus greatly power requirements & increasing reliability
In 1964, introduced the System/360 computer, which used integrated circuits,
devices that contain multiple transistors on a single chip
In 1977, Apple Computer founded by teenagers Steve Jobs & Steve Woznisk,
introduced the Apple II personal computers
In 1981, IBM introduced the Personal computer which soon dominated the
market

7. DESIGN CONCEPTS IN DIGITAL
COMPUTERS
Numbers System in Computers
Decimal Number (base-10):
6 x 10^3 = 6000
9 x 10^2 = 900
4 x 10^1 = 40
5 x 10^0 = 5
__________________________________________________
Sum = 6945

8. Binary Number (base-2)
 Consider the number 11 in binary notation
1 x 2^3 = 8
2 x 2^2 = 0
3 x 2^1 = 2
4 x 2^0 = 1
_____________________________________________
Sum = 11
Uses of Binary System:
 Only 2 digits are needed to specify any whole number
 The binary system is the easiest of model in the mechanical or electronic
computing machine
 2-3 takes 2 bits, 4-7 takes 3 bits, 8-15 takes 4 bits & so on.
 1 byte = 8 bits
 The largest integer that can be represented by a single byte is 255
 The most significant bit is often used for sign indicator -> become half
 2^n-1 e.g. 4-byte integers -> (2^32)-1 = 4,294,967,295
Base10 Binary
0 0000
1 0001
2 0010
3 0011
4 0100
5 0101
6 0110
7 0111
8 1000
9 1001
10 1010
11 1011

9. Octal base (base-8)
 To convert from binary to octal
 Group the binary numbers into a group of three bits starting with least significant bit
For example
100 010 001 111 => 42178
Decimal 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Hexadecimal 0 1 2 3 4 5 6 7 8 9 A B C D E F 10

10. Hexadecimal base (base-16)
 For the same number the hex conversion will be
1000 1000 1111 => 88F16
Decimal 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Hexadecimal 0 1 2 3 4 5 6 7 8 9 A B C D E F 10

11. For the same number the decimal conversion will be
1 x 2^11 = 2048
0 x 2^10 = 0
0 x 2^9 = 0
0 x 2^8 = 0
1 x 2^7 = 128
0 x 2^6 = 0
0 x 2^5 = 0
0 x 2^4 = 0
1 x 2^3 = 0
1 x 2^2 = 4
1 x 2^1 = 2
1 x 2^0 = 1
SUM = 2191

12. DESIGN CONCEPTS IN DIGITAL
COMPUTERS
Algorithms: is a sequence of actions that will bring about the solution to a
particular problem.
For Example : two integer -> largest factor i.e X % Y = 0
 2666/1798 ---- remainder 868
 1798/868 ---- remainder 62
 868/62 ---- remainder 0
Turning: Show that any finite algorithms could be reduced to a series of 0s & 1s on the tap, along with
the finite set of instruction for his machine
Engineers: how engineers solve problems
1. Choose those variables important to the problem at hand
2. Model the interrelation of the significant variables mathematically
3. Math is converted to algorithms
4. If computer is used, algorithms is converted to a series of binary instruction
5. Result is compared to what happens in the universe
6. If successful, the problem is solved, if not, repeat all steps

13. BASIC BUILDING BLOCKS IN A
COMPUTER
1. Memory: A basic need in the computer, the ability to store a number. The physical device that
allow this storage is call a ‘flip-flop’ because it ‘flips’ up to a high voltage or ‘flops’ to zero
voltage. The unique feature of flip-flop is that until it is signaled to change, it stays set at
high or low voltage.
Go through Figure 4.2
Latch Input Output
0
0 0
1 1
1
0 0
1 1
latch
Flip-flop
input output

14. Central Processing Unit (CPU):
 Tasks like binary machine instructions by flip-flops, retrieve numbers from different locations, addition,
comparison of numbers and many more are done in this part of computer.
Computer Arithmetic
 Inputs (A & B) to produce Output (X) ; Truth table
 AND, OR , NOT, NAND, NOR
Level of Computer Language
 Machine Language (0-1)
 Assembly Language (English like commands)
 High Level Language (Fortran, C , Basic, OS)
 Operating System (OS): It is a fundamental interface through which the user loads the instructions onto the CPU, routes
output to printer, or saves work for later use.

15. GETTING STARTED
Hardware: It is a term used for computer & its peripherals e.g. Printer, Disk drives and
networks.
 Personal Computers: Supercomputer --- Handheld calculators
 CPU: 1980s -> Intel-IBM 8088 CPU based system
 Memory: specific part to store numbers
 Input: keyboards, modems (transmits computer data over the phone lines)
scanners (image into data ), punch cards (used on old mainframe computers),
pointing devices (mouse, trackball, joystick, light pen, touch screen),
electronic instruments (temperature sensors, pressure sensors) &
music keyboards
 Output: Monitors, modems, printers, electronically controlled instruments.
 Storage Devices: Hard disk drives, floppy disk drives, tape storage system &
CD-ROM
Internal
Memory
Processing
Unit
Arithmetic
Logic Unit
CPU
Output
Devices
Input
Devices
Storage
Devices

16. READ OUT !
Printers
Floppy Disk and Hard Drives
Local Area Networks (LAN)

17. GETTING STARTED
Software: It is a collection of instruction that directs computer hardware to
perform specific tasks.
 Files
Disk Operating System & Other Operating Systems
The Windows Environment
Writing Equations in Computers

18. CREATING COMPUTER PROGRAMS
Flowcharts
It is a schematic of the logic needed in an algorithm; it describes the sequential order in which
the steps are done
Structured Programming
CODE
Spaghetti code -> fast but hard to understand
Structured code -> slow than spaghetti code but easy to understand
STRUCTURE
Sequential -> one after another in sequence
Selection -> if else conditions
Repetition -> long loops

19. CREATING COMPUTER PROGRAMS
Top-Down Design
1. State the problem clearly
2. Describe the output & input information
3. Work the problem by hand for a specific set of data
4. Develop a general algorithms for the problem
 Decompose
 Stepwise Refinement
5. Test the data with a variety of data sets

20. Program of addition of two numbers