Lesson 1-3 Flashcards
refers to the symbols that represent people, events, things, and ideas. Data can be a name, a number, the colors in a photograph, or the notes in a musical composition
Data
refers to the form in which data is stored, processed, and transmitted
Data representation
is the process of converting information, such as text, numbers, photo, or music, into digital data that can be manipulated by electronic devices
Digitization
1s used to represent digital data are referred to as binary digits — from this term we get the word bit that stands for binary digit
0s and 1s
usually referred to simply as a file, is a named collection of data that exits on a storage medium, such as a hard disk, CD, DVD, or flash drive
Digital file
consists of numbers that can be used in arithmetic operations
Numeric data
only has two digits: 0 and 1
No numeral like 2 exists in the system, so the number “two” is represented in binary as 10 (pronounced “one zero”)
Binary number system
is composed of letters, symbols, and numerals that are not used in calculations
Examples of character data include your name, address, and hair color
Character data is commonly referred to as “text”
Character data
(American Standard Code for Information Interchange, pronounced “ASK ee”) requires seven bits for each character
is a superset of ASCII that uses eight bits for each character
For example, Extended ASCII represents the uppercase letter A as 01000001
Using eight bits instead of seven bits allows Extended ASCII to provide codes for 256 characters
codes are used for numerals, such as Social Security numbers and phone numbers
ASCII
”) uses sixteen bits and provides codes or 65,000 characters
This is a bonus for representing the alphabets of multiple languages
Unicode
is a variable-length coding scheme that uses seven bits for common ASCII characters but uses sixteen-bit Unicode as necessary
UTF-8
Plain, unformatted text
stored in a so-called text file with a name ending in .txt
ASCII
A group of eight bits
Usually abbreviated as an uppercase B
Use for file sizes and storage capacities
Byte
All of the data stored and transmitted by digital devices is encoded as
an abbreviation for binary digit, can be further abbreviated as a lowercase b
Bits
extensively used to describe storage capacity and network access speed
Bits and bytes
are used to quantify digital data
Kilo, mega, giga ,tera
Kilobit (Kb or Kbit) can be used for slow data rates, such as a 56 Kbps (kilobits per second) dial-up connection.
Kbps (kilobit)
is often used when referring to the size of small computer files.
KB(kilobyte)
is used for faster data rates, such as a 50 Mbps (megabits per second) Internet connection.
(Megabit)
is typically used when referring to the size of files containing photos and videos.
MB(Megabyte)
is used for really fast network speeds.
Gbit(Gigabit)
is commonly used to refer to storage capacity.
GB(Gigabyte)
refers to any technique that recodes the data in a file so that it contains fewer bits
reffered to as zipping
Data compression
provides a way to compress data and reconstitute it into its original state; uncompressed data stays exactly the same as the original data
Lossless compression
throws away some of the original data during the compression process; uncompressed data is not exactly the same as the original
Lossy compression
Software for compressing data is sometimes referred to as a
utility or a zip tool
The process of reconstituting files is called
extracting or unzipping
compressed files may end with a
.zip, .gz, .pkg, or .tar.gz
is a multipurpose device that accepts input, processes data, stores data, and produces output, all according to a series of stored instructions
Computer
is whatever is typed, submitted, or transmitted to a computer
Input
is the result produced by a computer
Output
performing calculations, modifying documents and pictures, drawing graphs, and sorting lists of words or numbers
Process data
Processing is handled by the computer’s
Central Processing unit(CPU)
The instructions that tell a digital device how to carry out processing tasks are referred to as a
Computer program
, Software
Software
means that a series of instructions for computing a task can be loaded into a computer’s memory
Stored program
Tree main types pf software
Application software
System software
Development tools
is a set of computer programs that helps a person carry out a task
Application software
is to help the computer system monitor itself in order to function efficiently (an example of system software
example: computer operating system or OS
System Software
is to help the computer system monitor itself in order to function efficiently (an example of system software is a
Development tools
is to help the computer system monitor itself in order to function efficiently (an example of system software is a
Digital electronics
is to help the computer system monitor itself in order to function efficiently (an example of system software is a
system board
refers to the size and dimensions of a device or components, such as circuit boards and system units
Form factor
is tech speak for the part of a digital device that holds the system board
System unit
Four components of digital devices that require maintenance
System unit
Keyboard
Screen
Battery
designed to repel oils from fingertips
Oleophobic coating
can overheat, and in the worst case, they can explode
Present in battery powered digital devices
Lithium ion battery
Types of “Big computers”
Supercomputers
Mainframes
Servers
considered the fastest computers in the world at the time of construction; can tackle complex tasks other computers cannot; typical use includes breaking codes, modeling weather systems, and simulating nuclear explosions
Supercomputers
a large and expensive computer capable of simultaneously processing data for hundreds or thousands of users; looks like a closet-sized cabinet; used to provide centralized storage, processing, and management for large amounts of data
Mainframes
“serves” data to computers in a network; Google search results are provided by servers; about the size of a desk draw and mounted in racks of multiple servers
Servers
is designed to meet the computing needs of an individual
A personal computer (PC)
Personal computers can be classified as
Desktops
Portables
Laptops
Tablets
Smartphones
fit on a desk and run on power from a wall outlet; keyboard is typically separate from the monitor; popular in offices and schools
Desktops:
: run on battery power; their components are contained in a single case for easy transportation
Portables:
also referred to as a notebook computer; small and lightweight with a clamshell design and keyboard at the base
Laptops:
is a portable computing device featuring a touch-sensitive screen used for input and output; uses a specialized
Tablets: a tablet computer
configuration has a narrow frame screen that lacks a physical keyboard; Apple iPad is a slate tablet
a slate tablet
mobile devices with features similar to a tablet computer; provide telecommunications capabilities over cell phone networks
Smartphones
Just a tad larger than a deck of cards; the Raspberry Pi can be connected to a keyboard and screen for a full computer experience
Raspberry Pi
are handheld devices that can store and play music; iPod touch is a portable media player
Portable media players
multifunctional devices that include a camera, thermometer, compass, calculator, cell phone, GPS, media player, and fitness tracker
smartwatches
monitor your steps and heart rate
Activity trackers
Fitness tracker
smart appliances
The most popular digital devices are
desktops, laptops, tablets, and smartphones
Computers that operate essentially the same way and use the same software are said to be
compatible or having the same “platform”
You can assess whether two computers are compatible by checking their operating systems
is an integrated circuit designed to process instructions
It is the most important, and usually the most expensive, component of a digital device
microprocessor
technology was originally designed by ARM Holdings, a British technology company founded by Acorn Computers, Apple Inc., and VLSI Technology
ARM processors are energy efficient — an important characteristic for battery-powered devices
ARM
C++, BASIC, COBOL
Programming language
that corresponds to the microprocessor’s instruction set
Machine language
is part of the microprocessor that performs arithmetic operations, such as addition and subtraction
ALU(arithmetic logic unit)
refers to the process in which a computer executes a single instruction
Instruction cycle
Machine language instructions for programs are held in memory; when the program begins, the memory address of the first instruction is placed in a part of the microprocessor’s control unit called an
Instruction pointer
Microprocessor clock
means a billion cycles per second
Gigahertz (GHz)
A microprocessor that contains circuitry for more than one processing unit is called a
multi-core processor
the processor must complete all steps in the instruction cycle before it begins to execute the next instruction
serial processing
When a processor begins to execute an instruction before it completes the previous instruction, it is using
pipeline processing
executes more than one instruction at a time and works well with today’s multi-core microprocessors
parallel processing
(pronounced “cash”) is a special high-speed memory that allows a microprocessor to access data more rapidly
CPU cache
refers to the number of bits that a microprocessor can manipulate at one time; it limits the amount of memory that the processor can access
Word size
reduced instruction set computer
A RISC
complex instruction set computer
CISC
(random access memory) is a temporary holding area for data, application program instructions, and the operating system
RAM
(read-only memory) is a type of memory circuitry that is housed in a single integrated circuit on the system board
ROM
tell a digital device how to start
boot loader
the hard drives, CDs, DVDs, flash drives, solid state drives, and memory cards that contains data
storage medium
– the mechanical apparatus that records and retrieves data from a storage medium
storage device
represents data by magnetizing microscopic particles on a disk or tape surface
Magnetic storage
contains one or more platters and their associated read-write heads
A hard disk drive
– the average time it takes a computer to locate data on the storage medium and read it
access time
the amount of data a storage device can move per second from the storage medium to RAM
data transfer rate
, which represents data as microscopic light and dark spots on the disc surface
optical storage
(sometimes called flash memory) stores data in erasable, rewritable circuitry, rather than on spinning disks or streaming tape
solid state storage
, meaning the circuits retain data without an external power source
non-volatile
is a flat, solid state storage medium commonly used to transfer files from digital cameras and media players to computers
Memory card
) is a package of flash memory that can be used as a substitute for a hard disk drive
A solid state drive (SSD)
is a portable storage device that plugs directly into a computer’s system unit using a built-in USB connector
A USB flash drive
is housed on an external device that can be accessed from a network
Remote Storage
Remote storage can also be available as an Internet service, in which case it is called
cloud storage
the more places your data is stored and the more networks on which it travels, the more susceptible it becomes to intercepts from hackers and government spying agencies
Security and privacy risks
when a cloud storage site has an outage, all the data stored there becomes temporarily inaccessible
Service outages
some cloud storage providers have closed down their services with little warning
Discontinuation of service
Your documents, photos, music, videos—all the goodies that you’ve created and gathered—can be difficult or impossible to reconstruct from scratch
Data files
How much time did you spend customizing your home screen, entering contacts, choosing passwords, and setting preferences for your favorite apps? No one wants to have to do that all over again!
settings, accounts and profiles
they expand the options for input, output, and storage
expansion ports
A common wireless technology for connecting peripherals is
Bluetooth
is software that helps a peripheral device establish communication with its host device
device driver
technology produces an image by filtering light through a layer of liquid crystal cells
LCD (liquid crystal display)
algorithms gather data, analyze it, and then carry out the required actions
sense-plan-act algorithms
Sensors on the vehicle gather raw data about the nearby environment and the status of the vehicle itself. Environmental data comes from sensing nearby vehicles, people, animals, and other objects, as well as the roadway itself. Vehicle status data includes speed, direction, angle, and altitude. Sensor data is delivered to an onboard computer, where software quickly processes the input to identify road hazards and navigational points.
sense
Based on its interpretation of sensor data, the onboard computer applies a series of rules to determine the best course of action. For example, if radar data indicates that the vehicle ahead is slowing down, the computer must decide whether to adjust its speed or change lanes. The decision is based on rules such as “If the vehicle ahead slows down gradually, and the left lane is clear, then move to the left lane.”
plan
After the computer determines a course of action, it sends signals to the vehicle’s control systems. A signal to the car’s steering system can initiate a lane change. Signals could also be sent to the car’s throttle or braking system to achieve a change in speed.
act
(light detection and radar) is a key input for the computer algorithms that steer an autonomous vehicle, but radar, sonar, infrared, GPS, cameras, and internal navigation systems also supply essential data
Lidar
adds more data about the nearby environment. Radar, which uses sound waves, does a good job of sensing metallicobjects, but does not sense pedestrians and other non-metallic objects. It is primarily used to track nearby vehicles. It is currently used in adaptive cruise control systems to maintain a safe distance to the car in front.
Radar
uses orbiting satellites to determine a vehicle’s position. The coordinates received from the GPS are cross-referenced with digital road maps. Civilian GPS is accurate to about ten feet, but augmentation technology improves location accuracy. Soon, augmented GPS systems should be able to calculate position with accuracy of one inch.
GPS
sensors can be used to sense the heat signatures of pedestrians and animals, particularly when it is dark.
Infrared
(INS) include gyroscopes and accelerometers that continuously calculate position, orientation, and speed of the vehicle.
Internal navigation systems
