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Introduction to Computing

Hey everyone! In this blog, I wanted to continue my series of sharing a little peak into my class lecture notes! In this blog, I will be focusing on my course CS008.


I thoroughly enjoyed taking this class, and found it important to share what I learned in this class.


CHAPTER 1 NOTES


Starting with the definition of what is a computer? This definition is crucial to understand the rest.


What does a comp do? 

  • Computer: a programmable, usually electronic machine that converts raw data into useful information

  • Compared to other machine, most computers are general purpose machines, so they can be programmed to do different things


Information processing cycle: Process that converts data into information

  • Input: raw data entered

  • Processing: raw data manipulated to create useful information

  • Storage: info stored for later retrieval

  • Output: info returned to the user


History of computers 19th century

  • Joseph marie jacquard

  • Jacquard loom, punched cards, one of 1st programmable machines

  • Charles babbage

  • Made analytical engine (mechanical computer), had all basic components of modern day computers, programmable (punched cards), never completed bc tech of time was too limited  

  • Ada lovelace

  • Created programs (on punched cards for analytical engine), considered to be first programmer


History of computers 20th century

  • Alan turing

  • Father of AI, turing test, helped break nazi communication codes during ww2

  • Grace hopper

  • Accidentally coined term ‘computer bug’, created first compilers

  • Bill gates

  • Founded microsoft

  • Steve jobs

  • Founded apple


Definitions

  • ENIAC - 1st working digital general purpose electronic computer

  • UNIVAC - 1st commercially available computer, famously predicted outcome of 1952 presidential election


History of computers 4 GENERATIONS

  1. First gen 1940

  • Used vacuum tubes to store n process data

  • Were massive in size, not reliable, extremely slow

  • Programming done by manipulating switched which took days

  1. Second gen

  • Used transistors to process data

  • Faster, smaller, more reliable and cheaper than first generations computers

  1. Third gen

  • Used integrated circuits (computer chips) that contain large numbers of transistors to process data

  • Faster, smaller, more reliable and cheaper than second gen computers 

  1. Fourth gen

  • Basically an extension to third generation

  • Microprocessor - a complex integrated circuit that contains processing circuitry

  • First microprocessors developed were as powerful as the ENIAC

  • Central processing unit cpu - the main microprocessor in a computer

  • Faster, smaller, more reliable and cheaper than third gen computers

  • Personal computers developed 


Moore law

  • Prediction made in 1965 by gordon moore who co founded intel

  • Said that number of transistors that could be placed on a computer chip would double every 2 years for at least a decade

  • Actual pace was closer to every 18 months

  • Pace actually held up until roughly 2016 about 50 years, not just a decade

  • More transistors on a chip → faster and more powerful the chip is


Bits and Bytes

  • Humans count using 10 digits

  • Comp use transistors and switches, which only allow 2 possible values

  • True or false, yes or no, 1 or 0

  • Inside comp transistor can hold electricity or not

  • Known as binary number system 

  • All data entered into comp must be converted into bits (binary digits)

  • Numbers, characters, images, audio, video


Binary Digits and Codes

  • Bit - binary digit

  • Smallest unit of digital data

  • Basically equated to a single transistor on a computer chip

  • Can have only 2 values - 1 or 0

  • Single bit not very useful - only 2 values - but can use string of bits to represent more values

  • 2 bits 4 values

  • 3 bits 8 values

  • 8 bits 256 values

  • Byte - unit of measurement that equals 8 bits

  • To represent characters, each symbol - letter, digit, punctuation mark - needs to be given unique sequence of bits

  • ASCII / Extended ASCII

  • Developed for English, later expanded for similar “Romance” languages

  • Uses 8 bits (1 byte) for each character

  • Example: A = 0100 0001

  • Example: a = 0110 0001

  • Example: 0 = 0011 0000

  • Example: ? = 0011 1111

  • Cannot be used to represent characters from other languages

  • So what about Chinese, Japanese, Tagalog, Hindi, Russian, etc.

  • Unicode

  • Developed in early 1990’s to handle other languages

  • Uses 16 bits (2 bytes) for each character (instead of 8 bits / 1 byte)

  • Backwards compatible with ASCII

  • Can be used to represent characters from (almost) all languages

  • Has been universally adopted

  • Using a standard binary code like Unicode is critical for communication

  • If one computer sends data to another computer using a different binary code, it will not be understood (unless it is translated)

  • Could the web function as smoothly as it does today if different computers all over the world used different binary codes?


Measuring Data

  • Storage capacities (such as on hard drives and in computer memory)

  • 8 bits = 1 byte

  • 1 Kilobyte (K) = 1,000 (1 thousand) bytes

  • 1 Megabyte (M) = 1,000,000 (1 million) bytes

  • 1 Gigabyte (G) = 1,000,000,000 (1 billion) bytes

  • 1 Terabyte (T) = 1,000,000,000,000 (1 trillion) bytes

  • 1 Petabyte (P) = 1,000,000,000,000,000 (1 quadrillion) bytes

  • etc.

  • Bits used to measure transfer rates (such as an Internet connection)

  • 1 Kilobit = 1,000 (1 thousand) bits

  • 1 Megabit = 1,000,000 (1 million) bits etc.


Personal computers

  • Desktop Computers

  • Fits into a workspace, such as a desk

  • Not portable

  • Offer most speed, power, and upgradability for lowest cost

  • All-In-One: integrated monitor and system unit

  • Notebook (Laptop) Computers

  • Portable

  • Can be as powerful as desktop computers, but will be more expensive

  • Convertible notebook

  • Two-in-one notebook

  • Subnotebook Computers

  • Smaller and lighter than notebook computers

  • As powerful as desktop and notebook computers, but even more expensive

  • Netbook Computers

  • Inexpensive notebook computer

  • Not very powerful

  • Mainly used for Internet access

  • Have largely been replaced by tablets

  • Microsoft Windows

  • Most popular (by far)

  • Mac OSX

  • Linux (Chromebooks)


Mobile Devices

  • Portable, handheld computers used for business and entertainment

  • Fastest growing segment of computers in terms of sales, especially smartphones

  • Smartphones

  • Small computers that combine cellular phone service with Internet service, GPS, etc. (by installing apps)

  • Tablets

  • Larger and more powerful than smartphones, but not as powerful as desktop and notebook computers

  • Usually run same operating systems as smartphones

  • Wearables (ex: Apple Watch)


Multi User Computers

  • Systems that allow multiple simultaneous users to connect to them

  • Advantages include centralized resources and security

  • Much more powerful (and more expensive) than personal computers and mobile devices

  • Client / Server Computing

  • Server: A computer that provides services to and/or share resources with client computers over a network

  • Client: A computer (or device) that requests services from a server

  • Forms the basis of how networking and the Internet works

  • Supercomputers

  • Fastest, most expensive computers in the world

  • Can be a single computer or a group of computers that work together

  • Perform complex mathematical calculations, such as those used in weather forecasting and medical research

  • Usually found in major universities and research institutes

  • Speeds normally measured in petaflops: 1 petaflop = one thousand million million (1015) floating-point operations per second

  • top500.org

  • Mainframe Computers / Enterprise Servers

  • Large, very fast computers primarily used by large organizations for critical applications and bulk data processing

  • Can have thousands of concurrent users

  • Midrange Computers / Minicomputers

  • Computers that are larger, more powerful, and more expensive than desktop computers but smaller, less powerful, and less expensive than mainframe computers

  • Can have dozens or hundreds of concurrent users

  • Primarily used by medium-sized companies

  • As high-end desktops have become more powerful, fewer companies are using midrange computers


Ergonomics

  • Study of the relationship between workers and their workspaces

  • Jobs involving mostly using computers can lead to health issues (over time)

  • Carpal tunnel syndrome (most common)

  • Eye strain / headaches

  • Back issues

  • Etc.


Distributed Computing

  • Distributes the processing of a task across a group of computers

  • With distributing computing, a group of less powerful computers can often perform same tasks as more powerful (and more expensive) computers

  • Grid Computing

  • Form of distributed computing using a group of computers in one location

  • Volunteer Computing

  • Form of distributed computing that uses computers from around the world

  • SETI@home


Computers are Everywhere

  • Ubiquitous Computing

  • Technology that recedes into the background and becomes part of the environment

  • Also known as invisible computing

  • Is all around us but has become so commonplace we do not notice

  • Embedded Computer

  • A specialized computer that is part of another device

  • Gasoline pumps, microwave ovens, traffic lights, etc.

  • Internet of Things (IoT)

  • The connection of the physical world to the Internet

  • Devices located, monitored, and controlled by embedded computers

  • Example: Smart homes

  • Convergence

  • The integration of different technologies onto multifunction devices

  • One device can replace multiple devices

  • Most common example: smartphones


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