Midterm Study Flashcards
4 basic functions of computers
- receive input
- Process information
- produce output
- store information
which 2 streams of evolution did modern computers result from
•mechanization of arithmetic »calculating machines (hardware) --eg, calculator •concept of stored programs »process control (software) --eg, programs and apps; tell computer what task to perform and how to perform them
mechanization 1:
the abacus
Blaise pascal
pascal’s adder
•the abacus --unknown origin --used in china 3-4 thousand years ago •Blaise Pascal (1623-1662) --first mechanized adding machine --gears and wheels --add and subtract, calculate taxes --inaccurate
mechanization 2
Gottfried Wilhelm Leibniz
•Gottfried Wilhelm (von) Leibniz (1646-1716)
•1670’s - liebniz calculator
–similar to pascals design
add, subtract, multiply, divide
–more reliable and accurate; but still inaccurate
–he also invented calculus
stored program 1
Joseph Marie jacquard
jacquard loom
•1800 France - Jacquard’s loom
–weaving loom
-metal punch cards to position threads for the weaving process
-within the decade, 11000 used in France
may have been first cause of unemployment by automation
stored program 2
Herman hollerith
Herman Hollerith 1860-1929 USA; tabulating machine
- machine that used electrical charges to read info off punch card
- for use in 1890 US census
- store and process census data on punched cards
- stared company in 1896; in 1924 this became IBM
Charles babbage
•1822-33 E. - difference engine
-abandoned bc not precise
•1830-71 - analytic engine
-designed but never completed; ahead of its time
-mill; arithmetic computations
-store; stored data and results
-operation cards; program instructions
-variable cards; select memory location of ops
-output; printer or punch cards
-first programmer: countess Ada Lovelace E.
the scientists and mathematicians who designed and build first working computer
- konrad zuse. GR
- John atanasoff. US
- howard Aiken.
- John mauchly & J Presper Eckert
Konrad zuse
- 1939, built first programmable, general purpose digital computer
- built from electric relays to automate engineering calculations
- “too lazy to calculate so I invented computer”
Alan Turing 1912-1954
- grandfather of computer science
- influenced group responsible for building the collosus
- a member of the team which broke the enigma code; sue by nazi Germany
- then created another machine to break enigma code and intercept nazi communications
- reportedly committed suicide
1939-42 - ABC
John atanasoff and Clifford berry (Iowa state)
-small scale - 30 vacuum tubes
mark 1
1944 -electromechanical computer -howard Aiken (Harvard) first real analytical engine -based on relays
John von neumann
1945 - Princeton
- developed stored program concept
- -both programs and data stored in same memory
- modern computers said to use von Neumann architecture
- worked on the ENIAC doing hydrogen bomb
ENIAC
electrical numerical integrator and calculator
- best known as first fully electronic computer
- 18000 vacuum tubes
- 1500 relays
- 30x50ft room
- low reliability, lots of power, air conditioning
- six women did most of programming incl Grace Hopper
UNIVAC 1
- first commercially available electronic digital computer
- introduced by Remington rand
- public awareness of computers increases as it correctly predicts that Eisenhower will win presidency 1952
evolution and acceleration
hardware changes are defined by generations
- 1st gen vacuum tubes
- 2nd gen transistors
- 3rd gen integrated circuts
- 4th gen microprocessor
first gen computers
- 1930-40s
- vacuum tubes used as switches
- large computers
- very slow
- prone to failure
- incl, ABC, mark 1, ENIAC, UNIVAC etc
second gen computers
- 1950s to mid 1960’s
- transistors used as switches
- smaller than vacuum tube built computers
- as much as thousand times faster than first gen computers
- more reliable and less expensive
third gen computers
late 1960s
- hundreds of transistors packed into single integrated circuit on a silicon chip
- dramatic reduction in size and cost
- significant increases in reliability, speed, and efficiency
- mass production techniques to manufacture chips inexpensively
fourth gen computers
- 1970s to present
- complete computer on a chip
- radical change in appearance, capability and availability of computers
personal computers; 1975
- CPU or processor
- contained on a single chip called a microprocessor
- brains of the computer
two basic components of the CPU
- control unit
- -tells the computer system how to carry out a program’s instructions
- arithmetic-logic unit (ALU)
- -performs arithmetic and logical operations
components of tower
- system fan
- floppy
- heat sink
- hard drive
- optical drive
- RAM modules
- Processors (CPU)
- Motherboard
- power supply
motherboard components
- heatsink and fan
- -CPU under
- video card
- memory
- power supply
- dvd burner
- hard drive
computer hardware vs internal hardware
Computer hardware refers to the physical parts of a computer and related devices. Internal hardware devices include motherboards, hard drives, and
RAM. External hardware devices include monitors, keyboards, mice, printers, and scanners.
multicore processors
- 2 or more separate and independent CPU within a system unit
- -quad core supports 4 core processes
parallel processing
- computers ability to divide tasks into parts that can be distributed across each core
- windows 10 and MacOS sierra support parallel processing
integrated circuit benefits
- reliability
- size
- speed
- efficiency
- cost
embedded computer
special purpose computer that functions as a component in a larger product
- controlling temp of car
- monitoring heartrate
- monitoring house security
servers
slide 52 lecture 2
data representation: analog
signals are continuous and vary in strength and quality
data representation: digital
signals are in one of two states: on or off
binary system uses
two unique digits (0 and 1)
-bits and bytes
bit (binary digit)
- smallest unit of info
- contains one piece of info
- can have two values 1 and 0
what can binary digits, or bits, represent
numbers, codes, or instructions
decimal number system
decimal is a base 10, positional number system
10 digits: 0 to 9
powers of 10
eg, 8,652 = (2 x 10^0) + (5 x 10^1) + (6 x 10^2) + (8 x 10^3)
=2+50+600+8000
=8652
binary number system
binary is a use 2, positional number system
2 digits; 0 , 1
powers of 2
eg, 101102 = (0 x 2^0) + (1 x 2^1) + (1 x 2^2) + (0 x 2^3) + (1 x 2^4)
=0+2+4+0+16
=2+4+16
=22
counting in binary
use the bin method
32-16-8-4-2-1
slide 7 lecture 4
decimal to binary conversion
slide 22-24 lecture 4
byte
- made up of 8 bits of info
- byte can hold 256 dif values (0-255)
- 2 bytes is same as 16 bits
How many codepoints can be stored as 2 bytes?
65536
k (kilobyte)
about 1000 bytes of info
technically 1024 = 1K of storage
MB (megabyte)
about 1 million bytes of info
1024K in a MB
GB (gigabyte)
about 1 billion bytes of info
1024 MB in a GB
TB (terabyte)
about 1 million megabytes of information
1024 Gb in a TB
bar chart
compare data associated with a specific time period
pie chart
quick overview of data that can be divided into a limited number of categories
shows relative proportions of a whole
line chart
shows changes over time
scatter charts
shows relationship between variables
stock charts
shoes open, close, high, low and volume
clustered bar/column
use to see individual components
stacked bar/column chart
useful to work w data in a few categories that also has proportions of a whole that change over time
scatter chart
used to discover, rather then display a relationship between two variables
motherboard
main circuit board of computer
-copmuter chip contains integrated circuits
processor or CPU (central processing unit)
- interprets and carries out the basic instructions that operate a computer
- contain a control unit and an arithmetic logic unit
- performs arithmetic and logical data manipulations
- communicates w other parts of computer system
control unit of processor
the component that directs and coordinates most of the operations in the computer
arithmetic logic unit (ALU)
performs arithmetic, comparison, and other operations
processor
- For every instruction, a processor repeats a set of four basic operations, which comprise a machine cycle
- generates heat; could cause failure so need:
- -heat sink
- -liquid cooling
- -cooling pads
registers
contained in the processor
-temporarily holds data and instructions
system clock
controls timing of all computer operations
-pace of system clocks called clock speed, and is usually measure in GHz
processor speed
system clock
bus size
word size
architecture
compatibility
- software is written for specific processor and may not be compatible with another CPU
- every processor has a built in instruction set or vocabulary of instructions that only the processor can execute
- -CPUs in the same family are generally backwards compatible
sockets
-sockets; the connection point for chips
chips
- tiny circuit boards etched onto squares of silicon
- also called silicon chip, semiconductor, or integrated circuit
- mounted on chip carriers
slots
- provide a connection point for specialized cards or circuit boards
- provide expansion capabilities for the computer
bus lines
connecting lines the provide pathways to support communication among electronic components
chip capacities
expressed in word size
-word is number of bits that can be processed at one time: 16, 32, or 64
parallel processing
computers ability to divide tasks into parts that can be distributed across each core
memory
holding area for data, instructions and information
- contained on chips connected to the system board
- three well known types of memory chips
- -RAM
- -ROM
- -Flash memory
RAM
holds programs and data that the cpu is presently processing
–volatile or temporary-contents are lost when computer is powered off
cache memory
temporary, high speed holding area between the memory and CPU --additional RAM can be added using an expansion module called a DIMM
virtual memory
dividing a program between memory and storage enabling the system to run very large programs
ROM
read only memory
- info stored by manufacturer
- non volatile and can’t be changed
-CPU can read, or retrieve data and programs in ROM but computer cannot change ROM
- contains special instructions
- -start computer
- -access memory
- -handle keyboard input
flash memory
combined features
- RAM; can be updated
- ROM; non volatile
- contains startup information
- -BIOS
- -amount of RAM
- -type of keyboard, mouse, and secondary storage devices connected
how much info/data every 2 days
5 exabytes
until 2003 that was how much was ever made
Data
collection of unprocessed items
- text
- numbers
- images
- audio
- video
database
-collection of data organized in a manner that allows access, retrieval, and use of that data
information
processed data
- organized
- meaningful
- useful
database software
often called database management system (DBMS) allows users to:
- create a computerized database
- add, modify and delete data
- sort and retrieve data
- create forms and reports from the data
data organization levels
characters, field, records, and tables (files)
character
one byte
-numbers, letters, space, punctuation marks, or other symbols
field
combination of one or more related characters
- field name
- field size
- data type
record
group of related files
-primary key is field that uniquely identifies each record
record
group of related files
-primary key is field that uniquely identifies each record
table (data file)
a collection of related records
relational database
stores data in multiple tables that are linked via a relationship using common fields
divide data into objects
-usually a natural division
advantages of relational database
- reduce data redundancy
- -most items stored in one place
- -common field is only repetition
- improved data integrity
- -need only change one data entry
- shared data
- -easily share data over multiple tables
- flexibility
- -can retrieve and organize data dynamically
relational database design
-we need to define how we divide data into tables, records and fields, then determine the types of relationships that exist
- done through an entity relationship diagram
- -primary keys
- -foreign keys
- -relationship types
entity
the person, place, thing etc, about which you maintain information
easily identifiable
attribute
each characteristic or quality describing an entity
primary key
unique identifier for each record
foreign key
the primary key from another related table is stored as a foreign key to make sure the tables relate to each other
weak entity
entity that has no key that uniquely identifies it
input
any data and instructions entered into the memory of a computer
common input methods
- keyboard
- pointing devices
- touch screens
- pen input
- motion input
- voice input
- video input
- scanners and reading devices
colour depth of grayscale
bits per pixel
1bpp = 2 levels (black or white
4bpp = 16 levels
8bpp = 256 levels
what does colour depth/bpp affect
the overall texture/details of an image
Digital camera - light
CCD
charged coupled device
Digital camera - light
CMOS
complementary-metal oxide semiconductor
- light sensitive diodes that convert light to electrical charge
- aligned as a grid of pixels (picture elements) which creates a discrete division of the continuous world
- the number of pixels that make up the image is the resolution of the image
digital cameras - colour
-to capture the colour at each pixel a colour filter is placed between the light source and the diodes
-bayer filter - RGB colour filter arranged in alternating red/green and green/blues
colour calculation happens in the processor not by the sensor itself
for every pixel how many sensels are used
9
8 surrounding senses contribute to the main senses in the middle which is in the location of the target pixel
digital cameras- demosaicing
the process of combining the r,g,b pixels to form the true image (non-mosaic)
digital cameras - mosaic
after you have measured the amount of rgb hitting the corresponding pixels you have a mosaic of colours
digital cameras - interpolation
using the amount of rgb in neighbouring pixels to determine the true colour at each pixel
digital cameras - ADC
analogue to digital converter
- converts the measurements into binary values
- colour depth - bits per pixel (24-bits)
how big is an image
for 4M pixels (2000x2000), the size of a 24bpp colour image is :
2000x2000x24bpp=96Mbits, or 96M bit / 8 = 12MB
for 4M pixels, the size of 8bpp grayscale is:
2000x2000x8bpp=32M bits, or 4MB
pixel density
pixels-per-inch or ppi
- defines the physical size of each pixel
- eg, tv has 100ppi; iPhone 5 has 326 ppi
this is why text on your TV looks worse than on your computer display, even though they have the same resolution
sound - sampling
in signal processing, sampling is the reduction of a continuous-time signal to a discrete-time signal. a common example is the conversion of a sound wave (a continuous signal) to a sequence of signals (a discrete-time signal)
each sample musty fit into a binary value to be stored
sampling - dots
each dot (or sample) is represented by a binary number
A/D vs D/A conversion
microphone to computer digital audio is A/D (analog to digital)
computer digital audio to speakers is D/A (digital to analog)
sound wave
measure of compression and rarefactions over time
amplitude
the amount of pressure exerted by the wave
- measure of how big the compression/rarefaction are
- corresponds to how loud the sound is
encoded as a binary number
sound waves - frequency
the number of complete cycles (one compression and rarefaction) per second
- corresponds to the pitch of the sound
- high frequency = high pitch
audio digitizers
contain circuitry to digitize sound form microphones and other audio devices
digital audio - sample encoding
typically encoded as 8 or 16 or 24 bit number
rate of sampling
(samples per second, Hz)
typically uses 44,100 Hz, 48,000 Hz, 96,000 Hz, etc
digitizing sound
need to convert analog sound wave into digital sound wave
-done by sampling sound wave, generating sequence of discrete values representing the wave
sample rates
number of samples taken per second
bit depth
number of bits used per sample
what affects the quality of the sound representation
both bit depth and sample rate
CS quality sound
sampling rate = 44,100 sample/sec
audio bit depth = 16bits/sample * 2 tracks
44,100162=1,411,200bits/sec or 176,000 bytes/sec
average song = 3 min
32MB per song
British dude video script
http://www.projectstudiohandbook.com/videos/playlists/digital-audio/what-is-digital-audio/what-is-digital-audio-script.php
HTML
HyperText Markup Language
- collection of markup tags
- defines the various components of a WWW document
- HTML docs are plain text (ASCII) files that can be created using any text editor; must have a .html file extension
HTML
HyperText Markup Language
- collection of markup tags
- defines the various components of a WWW document
- HTML docs are plain text (ASCII) files that can be created using any text editor; must have a .html file extension
HTML tags explained
- an element is a fundamental component of the structure of a text document; eg, heads, tables, paragraphs etc
- use HTML tags to mark the elements of a file for your web browser
- eg, <h1> and </h1>
- NOT case sensitive
- may include an attribute; eg,
