com sci test 1

computer

 is a device that receives, stores, and process information

von Neumann archetecture

1. Input/output Devices(I/O), these allow the user to interact with the computer 

2. Memory, stores information to be processed as well as programs( instructions specifying the steps necessary to complete specific tasks 

3. Central Processing Unit (CPU), carries out the instructions to process information

CPU

Known as the brains of the computer responsible for controlling its inner workings

memory

• part of the computer that stores data and programs 

• Modern computers are digital devices, meaning they store and process information as binary digits (Bits)

N bits = 2^N values

Large collections of bytes can be specified using prefixes

2^8 =256 values

byte

8 bits

Kilobyte(KB)

2^10 bytes = 1,024 bytes (=8,192 bits)

Megabyte(MB)  

2^20 bytes = 1,048,576 bytes (= 8,388,608 bits)

gigabyte(GB)

2^30 bytes=1,073,741,824 bytes(=8,589,934,592 bits)

terabyte(TB)

2^40 bytes= 1,099,511,627,776 bytes(= 8,796,093,022,208 bits)

Main memory

data is stored as electric signals in circuitry, used to store active data

input device

allow the computer to receive data and instructions from external sources( E.X) Keyboard, mouse, scanner)

output device

allow the computer to display or broadcast its results (E.X. speaker, monitor)

software program

a sequence of instructions for the computer( more specifically the CPU) to carry out in order to complete some tasks

operating system

a collection of programs that controls how the CPU, memory, and I/O devices work togethe

Internet is hardware

consists of computers around the world and the communication between them that links them together.

web

consists of web pages, images, sound files, etc, and the software that stores and retrieves all the files 

important

The internet could exist without the web, but the web couldn’t exist without the internet

who was the World Wide Web invented by ?

Tim Berners Lee

web browser

a program that access that web page, interprets the contents and displays the page

web server

an internet-enabled computer that executes software for providing access to certain web document

Hypertext Markup Language( HTML)

utilizes tags to markup page contents

Hypertext transfer protocols (HTTP)

defines how messages between browsers and servers are formatted

cookies

a small file that can be stored and accessed by a web server

THe ARPAnet

(precursor to the internet) became a reality in 1969

“internet”

was coined in recognition of the similarities between the NSFNET and the interstate highway system

internet society

 an international not-for-profit organization (Founded in 1992)

packet switching

messages to be sent over the network are first broken into small pieces known as packets

1. Transmission control protocol 

2. Internet Protocol

the two central protocols that control internet communication

Transmission Control Protocol (TCP)

Controls the method by which messages are broken down into packets and them reassembled when they reach their final destination

Internet Protocol (IP)

Concerned with labeling the packets for delivery and controlling the packets’ path from sender to recipient

domain names

hierarchical names for computers

(e.g., bluejay.creighton.edu) they are much easier to 

remember and type than IP addresses