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Introduction to IT – C
Information Technology as a
Discipline Module 1: Introduction to
Information Technology The Big Picture of
Information Technology
Module 2: IT as a Discipline
History and Future of Computing
Module 7: The History of the Computer
The evolution of Computer Hardware: 1st Generation
1940 - 1958 ENIAC (Electronic Numerical Integrator and Computer) 1 st
general purpose computer Relied on vacuum tubes, Relied on relay switches Required programming to be in machine language
The evolution of Computer Hardware: 2nd Generation
1959 - 1965 Transistors replaced vacuum tubes, they were cheaper,
used less power and could last up to 50 years. Magnetic core memory - consisted of small rings made of magnetic materials, placed in a wire-mesh framework. Each ring stores one bit by having magnetic current rotate in either clockwise or counterclockwise fashion. External storage moved from magnetic tape to disk drives and disk drums Mainframe computers - computers built around a solid metal framework. First computers to use Boolean operators
The evolution of Computer Hardware: 3rd Generation 1966 -
1970 Integrated Circuits (ICs) could hold dozens of transistors and replace
magnetic core memories. So they would be used for both computation and storage.
Computer family – any computer in a given family should be able to run the same programs without having to alter the program code. Software development code was born because of the computer family. Computer networks were introduced that would allow individual users to connect to the computer via dumb terminals Dumb terminal – input/output device; doesn’t have memory or a processor.
The evolution of Computer Hardware: 4th Generation
1970 - Present
Single chip processor (micro processor) Word processing and accounting software Miniaturization – IC miniaturized at an exponential rate
Implications for Current and Future Computer Systems
Pipelined CPU - the fetch–execute cycle is performed in an overlapped fashion on several instructions. Moore’s Law doubling would increase every year, in reality the transistor count doubled every 18-24 months.
Evolution of Computer Software
1 st^ generations computers programmed in machine language IBM stopped producing their own software and the software houses were introduced.
Machine/Low-Level Languages
I/O was limited to reading punch cards or magnetic tape and written to magnetic tape Language translator (assembler) - This program would take another program as input and output a machine language version, which could then be run on the computer. The earliest language translators were known as assemblers, which would translate an assembly program into machine language. Assembly language, although easier than machine language, still required extremely detailed, precise, and low-level instructions.
High- Level Languages
2nd generation 1959 - Compiler – improved language translator FORTRAN - was primarily intended for mathematical/scientific computing.
PaaS – Platform as a Service -quickly and reliably develop and deliver applications. This form of cloud computing is offered as a service by some major organizations, such as Amazon and Google, and used extensively by app developers IaaS – Infrastructure as a Service - all the resources (e.g., servers, data storage) an IT department needs are located outside of the organization and are accessible by anyone, anywhere. Cloud Computing Benefits: Reduced costs Increased speed of development for projects The ability to quickly and easily scale operations Less reliance on internal IT expertise Globalization
Computer Classification and Infrastructure
Module 6 Components of Computer Hardware
The Structure of Computers
CPU - is the device that not only executes your programs’ instructions, but also commands the various components in the computer. Memory - stores the program(s) being executed and the data that each program is using Input/Output Subsystem (I/O) - includes all peripheral devices (input, output, storage, network) where storage consists of the long-term storage devices (disk drives, tape). Bus - consists of a number of wires, each wire allows 1 bit (a single 1 or 0, high or low current) to flow over it. Bit - (a single 1 or 0) Byte - (8 bits, using eight wires on the bus, usually the smallest unit of data transfer) Word - today, computers have either 32-bit or 64-bit words; the word size is the typical size of a datum)
The System Unit
Internal Components of the System Unit
- The case, which is a protective covering
- Internal bays and slots that grip the internal components ▪ Buses, which are the circuitry and electrical channels that enable communication among the electronic components ▪ Bays (external openings) and ports that connect peripherals ▪ Lights and indicators that show the computer is turned on ▪ Expansion cards, like a sound card or graphics card, are plugged into expansion slots and enhance the performance of a computer ▪ The memory module is attached to the motherboard and consists of electronic components that store instructions and data.
Central Processing Unit (CPU) - component that
does the computer’s main work of accepting data and
converting it to information.
Processor (chip) – carries out the instructions of a computer program. Control Unit (CU) - The control unit does as its name indicates—it retrieves the instructions and the raw data that is input, and coordinates or controls the sending of those instructions and data to the ALU. Arithmetic Logic – (ALU) - does the actual processing of the data, from mathematical calculations and logical operations (comparing values that can be numeric or alphabetical) to conversion of keyboard text entry to output display on your screen. System Clock - controls the speed at which instructions are processed. Processing speed is listed in terms of megahertz (MHz), (millions of processes per second) or gigahertz (GHz) (billions of processes per second), although today’s PCs have processing speeds in GHz only.
Memory
RAM – Short term storage. RAM can be read and written to Dynamic RAM (DRAM) – main memory or primary memory Static RAM (SRAM) cache memory and registers ROM – Long term storage, retains its contents indefinitely BIOS ROM – is stored on a chip on the motherboard. BIOS - Basic Input Output System, software that runs when a computer is first turned on. Both RAM and ROM is used to store programs
Storage Sizes
Size Meaning Example
Handhelds –
Mobile Device Peripherals
Notebooks Tablets Handhelds Smartphon es
Module 13: Types of Software
Categories of Software
Application Software - consists of programs that end users run to accomplish tasks. Productivity software consists of the applications that are useful to just about everyone. Productivity software includes the word processor, presentation software (e.g., PowerPoint), spreadsheet program, database management systems, calendar program, address book, and data organizer. System Software - consists of programs that make up the operating system. System software is software that directly supports the computer system itself and is typically started automatically. Daemons/Services - pieces of the operating system that run in the background all of the time. They wait for an event to arise before they take action Utilities – System Software that is run on demand Server Software – works with hardware to provide a network service (web servers, email servers and database servers)
Cloud Computing and Intranet
Local Applications – Software that is stored on an individual’s computer Intranet - LAN that uses the Internet Protocol. Applications intended for Internet usage (e-mail, web browsing, telnet/ssh, etc.) will work internally as easily as they work externally. Cloud Computing - combines several different technologies: distributed computing, computer networks, and storage area networks.
Operating Systems – a program whose task is to allow a
computer user to easily access the hardware and software of a
computer system. An OS is required to maintain the computer’s
environment.
The History and Future of Operating Systems
Early computers didn’t have an OS
They read from punch cards and wrote to tape Language Translators Resident monitor- created to handle operations based on a few commands rather than dozens or hundreds of program instructions.
Operating Systems Software Components
Kernel - The core components of the operating system are referred to as the kernel. The kernel is loaded when the computer is first booted. Included in the kernel are the components that handle process management, resource management, and memory management. Without these, you would not be able to start a new program or have that program run efficiently. The kernel sits on top of the hardware and is the interface between hardware and software. Device Drivers - Device drivers provide specific interfaces between the OS running a computer and hardware. Shell - An interface for the user that gives access to the kernel. Services - Services, or daemons, are operating system programs that are usually started when the operating system is loaded and initialized, but they run in the background. This means that the program, while it is active, does not take up any CPU time until it is called upon to do so. Utility Program - System utilities are programs that allow the user to monitor and improve system performance.
The User Interface of an Opening System
GUI - allows a user to control the computer by using the mouse and pointing and clicking at objects on the screen (icons, menus, buttons, etc.).
Server Software - software that works with hardware to provide a
network service.
Web Server – responds to HTTP requests. Proxy Server - is used in an organization to act as a giant cache of web pages that anyone in the organization has recently retrieved. Another function of the proxy server is to provide a degree of anonymity since the IP address recorded by the web server in response to the request is that of the proxy server and not the individual client. Proxy servers can also be used to block certain content from being returned; for example, rejecting requests going to specific servers (e.g., Facebook) and rejecting responses that contain certain content (e.g., the word “porn”). Database Server – Structured data repository. A database management system is software that responds to user queries to create, manipulate, and retrieve records from the database. FTP Server - An FTP server is like a webserver in that it hosts files and allows clients to access those files. FTP, access is in the form of uploading files and downloading files. Any files downloaded are saved to disk File Server - A file server is in essence a computer with a large hard disk storing files that any or many users of the network may wish to access. Email Server - An e-mail server provides e-mail service. Its job is to accept e-mail requests from clients, send messages out to other e-mail servers, receive e-mails from other servers, and alert the user that e-mail has arrived.
Computer system - a collection of components that work together to meet the needs of the user. These components are typically categorized as either hardware or software. In addition, networks and users are often considered to be part of a computer system. Hardware - includes the physical components of a computer system which include the system unit and its components (motherboard, fan, disk drives, CPU, memory chips) and peripheral devices, such as a keyboard, printer, or monitor. Software - Software is computer programs that tell the computer what to do - how to execute commands and process information. Network - a collection of computers and resources connected by various media so that they can communicate with each other. Users - those who use a computer.
Introduction to Hardware and Software
Hardware - physical components of the computer system. This includes all of the external physical components that you can see, such as: monitor, mouse, printer, keyboard, and case that contains the internal components. Software - software is intangible. Software is developed by writing a program that has some specific purpose. Software is often divided into two categories. Systems Software - includes the operating system and all the utilities that enable the computer to function. Applications Software - programs that do real work for users. For example, word processors, spreadsheets, and database management systems fall under the category of applications software
Introduction to Networks and Users
Users -In earlier days (1940s–1970s), most—if not all—processing was done without human interaction at all. The user specified the program, the source of input, the location of output, and sent the program off to run. Networks - Collection of computers and resources connected by various media so that they can communicate with each other. Protocol - set of rules established to govern how people behave and interact with each other. TCP/IP – collection of protocols referred to as a protocol stack.
The Network as a Framework of the
Computer Ecosystem
Module 8: Introduction to Computer
Networks Module 9: Network Hardware
Computer Network – is a collection of computers and computer
resources (printers, file servers) connected in such a way that the
computers can communicate with each other and their resources.
Local and Remote Computers
Local Computer - is the computer that the user is using. That is, the
user is physically present with that computer.
Remote Computer - A remote computer is a computer being
accessed over the network.
Computer networks can be viewed at a physical level (the
connections or physical media over which communication is
possible), a logical level (network topology), or a software level (the
protocols and programs that allow the computers to communicate).
Types of Media
Unshielded Twisted
Pair(UTP) Fiber Optic –
Light pulses
Coaxial cable – electric current transmission (10BaseT uses +2.5v or -
2.5V) Radio Signals - are sent via radio towers, cell phones towers and
bounced off satellites in orbit.
Broadcast Devices
Hubs - A network hub is a device that connects multiple
computers together. When there are multiple computers connected to
a hub, a message received by the hub is forwarded to all ports on
the hub. A destination address attached to the message indicates
which computer the message is intended for, but it does not prevent
other computers from picking up the message. A hub broadcasts
the transmission, as it sends the data to every device in the
network.
Switches - A network switch is a more functional connection than
a hub. For one, it records and recognizes the local network
addresses [Media Access Control (MAC) addresses of all computers
connected to the switch. A message is then only passed along to the
computer that matches the destination address. Thus, the switch is
able to utilize network bandwidth more efficiently. While a switch can
be used to broadcast to all computers in a network, its purpose is to
only send transmissions to a specific, intended computer.
Routers - The router is a device that connects multiple networks
together. Externally, there is little to differentiate a hub from a
switch from a router (other than perhaps the size). Internally, the
switch has more hardware, including storage space for MAC
addresses, than a hub. A router contains programmable routing
tables and includes at least one input that comes from another
network.
Ring - each device is connected directly to its neighbors, and
messages are forwarded from device to device until the proper
destination is reached.
Operating Systems and Applications
Module 12: Introduction to Computer Software
Software Licenses
Module 14: Software Licensing
Proprietary and Open Source Software
Proprietary, or commercial, software is purchased from a vendor. Such software may be produced by a company that commercially markets software (usually referred to as a software house), by a company that produces its own in-house software, or by a consultant (or consultant company) hired to produce software. Purchasing software provides you with two or three things The Software itself in exe form A license to use the software Helpful resources Shareware - Shareware usually provides you a trial version of the software.
Freeware - Freeware is usually software that has become obsolete
because a newer software has replaced it, or is software that the
original producer
(whether an individual or a company) no longer wishes to maintain
and
provide support for. You are bound by some agreements when you
install it, but otherwise you are free to use it as if you purchased it.
Public Domain Software - is software that has been moved into the
public domain. Like freeware, this is software that no one wishes to
make money off of or support.
Open Source Software - This software was created in the Open
Source Community and made freely available as source code. You
may obtain the software for free; you may enhance the software;
you may distribute the software. However, you have to abide by the
copyright provided with the software. Most open source software is
made available using the GNUs Public License, and some are made
available with what is known as a copyleft instead of a copyright.
Patents and Copyrights
Patents - Protects the creation of inventive concepts as well as the
tangible work product Patents will prevent others from making, selling,
or using the invention for 20 years from the application filing date.
Copyright - Protects an original work (in its tangible, expressed form),
but not the ideas behind the work. Copyrights have the exclusive
right to make copies, prepare derivative works, and distribute copies
of the work for the duration of the author’s life plus 70 years.
First Step: Identify an organization’s information assets (physical assets computer networks, people). Public – info gathered from a phone book (names and addresses). Sensitive – info that wouldn’t be a threat if others were to learn it. Telephone numbers and email addresses. Private - information that could be a threat if disclosed to others such as social security and credit card numbers, or health and education information. This information is often protected from disclosure by federal legislation. Confidential - information that an organization will keep secret, such as patentable information and business plans. Second Step: Identify Vulnerabilities of each asset. Third Step: Determine the threats that can exploit the vulnerabilities Fourth Step: Prioritize the risks Fifth Step: Develop and enact policies as
necessary Common Threats and
Vulnerabilities Social Engineering -
threat that targets users. Phishing - the process of targeting a specific individual, usually via email, under the guise of a reputable or trustworthy entity to reveal private or personal details such as usernames or password. SQL injections - an attacker issues an SQL command to a web server as part of the URL or as input to a form on a company's website. Buffer Overflow – an attacker inserts more than the buffer can hold Hacking - when an individual obtains unauthorized access to a host. White Hat - White-hat hackers are security professionals and hack for “good purposes” to find vulnerabilities and fix or protect against them. Black Hat - Black-hat hackers are individuals with malicious intent who violate security in order to commit crimes or acts of terrorism. Grey Hat Hackers - Hackers who engage in both types of hacking activities. Packet Sniffing - Packet sniffing is a means of obtaining a password; in reality, in addition to passwords, packet sniffing allows you to obtain anything being sent over the network if the data being transmitted is sent without encryption. Malware - term given to "malicious" software. Virus - software that attaches itself to another legitimate (or seemingly legitimate) software application. Trojan Horse - this type of virus completely replaces an existing application and takes the name of the taken over file. The Trojan horse pretends to be one piece of software but is, in fact, another. Worms - are self-contained programs and do not need other programs to propagate across computers and computer networks. Spyware - Spyware is often downloaded unknown to the user when accessing websites. The spyware might spy on your browsing behavior at a minimum, or report back to a website sensitive information such as a credit card number that you entered into a web form.
Denial of Service (DOS) - one or more attackers attempt to flood a server with so many incoming messages that the server is unable to handle legitimate business. Distributed Denial of Service (DDOS) - which is the same as a DOS, but instead of one hacker/host perpetrating the attack, the attack comes from many more hosts (possible controlled by one hacker) with all attacking hosts directed at a single target.
Mitigating Techniques
Firewalls AntiViral Software Symmetric key encryption - uses the same key for performing the encryption and decryption. Public-key encryption - uses two keys, a public and private key.
Security Best Practices
Authentication What you know – password What you have - 2 factor authentication What you are – biometrics
Software Architecture
Module 15: Programming and Scripting
Binary Numbers as the Foundation of Machine Language
Binary –(Base10) Number system that computers use. Decimal – Number system that people use in everyday life Hexadecimal (Base16)– Number system that represents binary in a shortened way, Is created by converting 4-bit binary numbers Octal –(Base8) groups of binary digits that make it easier to read a long string of numbers and also reduce storage size. Character Representation American Standard Code for Information (ASCII) Uniicode
Programming Language
Language translators - a program that takes one program, written in a high-level language, as input, and creates a machine language program as output. High level language (Programming language) - which are a vocabulary and set of rules for instructing a computer to perform certain tasks. BASIC, C, C++, Java and Python Machine language (01011011) Assembly Language (load a) High-level Programming language (init a=1, b=5)
High-Level Languages: Compiled and Interpreted
Software Architecture (MVC)
The Model – Where changes are made to the data based on new data. It is in the model layer that the business logic is designed. The View – represents the user interface. The view is used to capture input from the user to be passed on via the controller to the model. It is in the view layer of the application that the user interface logic is designed. The Controller - The user interacts with the controller, and passes along the user requests to the model. It is in the controller layer that the input logic is designed.
Data Storage and Analysis
Module 16: Introduction to the Management
of Data Module 17: Data Types and the
Power of Databases Data Types and Uses
String – Alphanumeric or text character (string data) Floating point $ or. Date – ?/?/ Boolean (Yes or
No) Database
Types
Flat File Database - A flat file database is used if the amount of data that is being recorded is fairly minimal. The most common example of a flat file is a CSV file (comma separated values). Records in a flat file are separated by a delimiter. In a CSV file, that delimiter is a comma. One of the advantages of the flat file format, is that these files can be easily imported into other programs that use a different file format; data can be captured through one program and then imported into another. Relational Database - A relational database is the most common structure for databases. Multiple tables with inter-related fields can be queried to generate reports and provide information to users. Hierarchical Databases - A hierarchical database format organizes data using a tree- like or organizational chart type structure. The main data points can have multiple sub-data points associated with them referred to as a parent-child model; however, the sub-data points can only have one main data point.
Data Organization in Databases
Records/Tuples – rows, all of the data listed fro a single person or entity. Attributes - characteristics which are used to describe a record, and are the column headings of a table_._ Field - type of data such as a number, a string, a date, a yes/no (or true/false) value.
Functionality of Databases
Projection - another form of query that returns all of the records from the relation, but only select attributes or fields. For instance, we could project the relation from a table to provide just the first and last names. Join - withdraws information from multiple relations.
Database Administration
Database Administrators responsibilities focus on the design,
development, and support of database management systems
(DBMSs).
A database administrator is often expected to play a role in
application design and development. This may be by assisting the
application developers with the design of the databases needed to
effectively support those applications. This requires a unique set of
skills that include database modeling, schema development,
normalization, and performance tuning.
Module 18: Data Management Tools
Business Intelligence
Business Intelligence System - is to help support management in their strategic decision-making process. Data Information Processing (Data Warehouses) Data Warehouse – Collection of organized databases The typical data warehouse uses an ETL (Extract, Transform, Load) process: Extract data - data comes from various sources. These sources must be identified and understood. Transform - given that the data come from different sources, it is likely that the data are not organized using the same collection of attributes. Therefore, the data must be transformed to fit the model(s) of the data warehouse. This will include altering data to relations or objects (or whichever format is preferred), recognizing the unique identifier(s), and selecting the appropriate attributes (fields). Load data - the transformed data must be stored in the data warehouse using the appropriate representation format. Datamarts - the means by which users obtain data or information out of the warehouse.
Database Information Processing (OLAP)
Online Transaction Processing (OLTP) Online Analytical Processing (OLAP) – Combination of analyzed data from various databases into a meaningful report Slicing – Slicing creates a subset of the data by reducing the data from multiple dimensions to one dimension. Dicing – Dicing is the same as slicing except that the result can be in multiple dimensions, but still obtaining a subset of the data. For instance, a dice might limit a three-dimensional collection of data into a smaller three- dimensional collection of data by discarding certain records and fields. Drilling up/down - Drilling up and down merely shifts the view of the data. Drilling down provides more detail and drilling up provides summarized data.
