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HARDWARE Data Processing (IPO) Input - raw data Output - processed HARDWARE - tangible / physical parts of the computer MAIN UNITS OF A COMPUTER: (IOMP) - Input - Output - Main Storage - Processor: Interprets and carries out basic instructions. PARTS OF PROCESSOR: (CARS) Control Unit: Passes da...

HARDWARE Data Processing (IPO) Input - raw data Output - processed HARDWARE - tangible / physical parts of the computer MAIN UNITS OF A COMPUTER: (IOMP) - Input - Output - Main Storage - Processor: Interprets and carries out basic instructions. PARTS OF PROCESSOR: (CARS) Control Unit: Passes data to ALU for processing Arithmetic Logic Unit: performs all calculation Registers: Small, high speed storage; temporarily holds data System Clock: Controls the timing; regular electronic pulse(ticks). TYPES OF MEMORY: (RRCm CMOS)​ RAM (Random Access Memory): A.K.A "Memory/Primary Storage". Is volatile and stores data for processing. Stores: Systems Software, Apps, Data. ROM (Read Only Memory): Contains stored instruction required; nonvolatile Cache Memory: for informations that are frequently used by CPU CMOS (Complementary metal-oxide semiconductor): Provides information everytime the computer is turned on e.g. Date/Time, Battery, Storage INPUT DEVICE: Peripheral device used to send data to computer. - MICR (Mark Interface Character Recognition): pang botohan - Touch Screen - Sensor - Speech Synthesizers: Speech to text OUTPUT Device: Device used to send data from computer to another device or user. - Printer - Monitor - Xerox - Speaker - Projector Other Hardware: Second or Auxiliary Storage Devices - Is where data is stored permanently outside the primary storage. Why store in Auxiliary? - Primary storage is limited - Data stored in primary are volatile and temporary Auxiliary Storage Devices (MEMOS) - Magnetic Tape: Data stored serially can only be accessed in serial manner. - Magnetic Disk: Direct access storage media. - Optical Disc (CD, DVD, Blu-ray): write data through light/laser beam rather than electromagnetic. - Solid State Devices: uses IC assemblies as memory. External Hard drive, flash drive, cloud. SOFTWARE SOFTWARE: Program which consists of step by step instructions 2 TYPES OF SOFTWARE: SYSTEM SOFTWARE: Program that control or maintain operations of the computer; interface between Apps, Hardware & User. APPLICATION SOFTWARE: Consists of programs that can make users productive. SYSTEM SOFTWARE​ TYPES OF SYSTEM SOFTWARE (Os, Up, C/I) ​ Operating System: ​ Utility Programs ​ Compiler/Interpreter Operating System: Collection of programs that coordinates all activities in hardware, manages computer internal workings, provides means for users to communicate to a computer. (OS Examples: IOS, MacOS, Android, Linux, Windows) Boot Operation: (BIOS, POST, CMOS) -​ When a computer is turned on, it must rely only on code stored in systems memory A.K.A "BIOS" BIOS (Basic Input/Output System) - A firmware that resides in ROM, performs series of task called POST (Power On Self Test) POST: Checks for various system components; results are compared with data in the CMOS. CMOS: Stores Configuration information. *If POST is successful then BIOS search for system files and load them into memory from storage* PROVIDING UI Providing UI: Interaction with software of user Types of UI: (CL, MD, GUI) ​ Command-Line Interface: Displays prompt, users type on keyboard, computer executes, provides textual output. ​ Menu-Driven Interface: User has a list of items and can make selection by highlighting ​ Graphical User Interface: Windows, Icon, pointers, menu, etc. Device Driver: small program that tells OS how to communicate Category of OS: Stand Alone OS: Can operate with or without a network Network OS: Coordinates how multiple users access and share resources on a network. (designed to support a network; resides on a server). OS provides users the capability of: - Managing files - Viewing Images - Uninstalling programs - Scanning Disks - Diagnosing problems - Screen Saver Utility Programs: Type of System Software that supports computer infrastructure. - Anti-Virus - Back-up - Disk Compression tool Compiler - converts entire source program into machine language Interpreter - Translates and executes code one statement at a time APPLICATION SOFTWARE​ APPLICATION SOFTWARE: Consists of programs that can make users productive. 2 types of Application Software: - Packaged - Custom Application Software Categories: ​ Business ​ Graphics and Multimedia -​ Desktop Publishing, Paint-image editing, Web Page editing ​ Home/Personal/Education ​ Communications ​ Email, Chat, videoconferencing PROGRAMMING LANGUAGES: Low Level Languages Machine Language - 1st Assembly Language - 2nd Procedural Languages - 3rd OOP Languages Software: Variety of Forms Open Source Software: for use, modification, redistribution; no copyright Shareware: Copyrighted software that is distributed at no cost for trial period. Freeware: Copyrighted software provided at no cost: distributed for free to expand the market. Public-domain Software: Software placed in public domain; no ownership. PEOPLEWARE IT GROUPS AND JOB TITLE Management Group ​ Computer Systems Manager -​ Performs planning, organizing, monitoring, controlling, and staffing of the project. -​ Must possess technical skills, knowledge of business processes, ability to communicate and motivate. ​ Systems and Procedures (Group) ​ Systems Analyst -​ Develop and apply principles to produce computer applications. Also design programming tools and knowledge based systems. ​ Computer Engineer -​ Tests computer components and systems by developing and designing hardware and software. Make computers more mobile or incorporate in other areas. Programming (Group) ​ Computer Programmer -​ Responsible for writing, testing, and maintaining detailed instruction or programs. -​ Must be a critical thinker, must pay attention to minute details, must have ingenuity, creativeness and imagination. Computer Operator ​ Computer Operator  -​ Sets up the processor, loads and unloads the program, and ensures proper and correct operations of the computer. ​ Data Encoder -​ Prepares and encodes documents to transform source documents into machine readable form. ​ Computer Librarian -​ Catalogues, stores, and secures processing storage media. ​ SPECIALIZATIONS Cyber, System and Network, Security and Forensics -​ This specialization focuses on application, data, and network security and the management of information technology security. Data Analytics and Data Science -​ Data collection, cleansing, and processing. Application of statistical analysis on data. Correlating disparate data, storytelling and visualization. Data and Database Administrator -​ Overall management of data resources in an organization and handling of security, availability, and accuracy of data. Software Development -​ This specialization focuses on programming and the development of sophisticated applications. Web Design and Application Development -​ Design and development of fully-interactive websites and online applications for internet deployment. Network, Information and Communications Technology -​ This specialization focuses on network applications and management. INTERNET Internet - An interconnected network of computers all over the world using a common set of interconnection standards, protocols, communicating and exchanging data with one another. J.C.R Licklider of MIT (1962) - American Psychologist and Computer Scientist -​ Envisioned a globally interconnected set of computers through which everyone could easily access. Pentagon’s ARPANET (1969) - Advanced Research Projects Agency -​ Became functional, liking scientific and academic research across the US. Lawrence Roberts - American Engineer; Founding Father of the Internet -​ The Principal architect of ARPANET Ray Tomilson - Sent the first email. 1972 - First public demo of ARPANET; initial application of electronic mail was introduced. 1983 - ARPANET adopted Transmission Control Protocol and Internet Protocol (TCP/IP) 1987 - there were nearly 30,000 hosts on the internet. -​ Adoption of TCP/IP standard made larger number of hosts possible. 1989 - World Wide Web was born. 1995 - First year the web became commercialized. -​ The Federal Networking Council (NFC) passed a resolution defining the term “Internet”. Internet is: -​ Logically linked by a globally unique address space called based on the Internet Protocol -​ Able to support communications using TCP/IP and other IP-compatible protocols World Wide Web - Collection of interlinked multimedia documents that are stored on the internet and accessed using a common protocol (HTTP). Web Page -​ Each electronic document on the web. Website -​ A collection of web pages. World Wide Web Consortium (W3C) - With 350 organizations being a member, W3C oversees research and sets standards and guidelines for many areas of the internet. Sir Tim Berners-Lee - British Computer Scientist; invented web in 1989 Tim’s 3 Fundamental Technologies: ​ HTML (HyperText Markup Language) - The markup language for the web.  ​ URI (Uniform Resource Identifier) - A.K.A “URL”. An address that is unique and used to identify each resource on the web. ​ HTTP (Hypertext Transfer Protocol) - Allows retrieval of linked resources across the web. Protocol - Is the formal specification that defines the procedures that must be followed when transmitting/receiving data. TCP/IP - Foundation protocols for the internet -​ Manages conversations between servers and web clients. HTTP - Is what browsers and web servers rely on for exchanging data -​ Information exchanging procedure standard between 2 communicating parties. HTTPS - A secure version of HTTP -​ An encrypted HTTP channel that encrypts all the information being exchanged. ISP (Internet Service Provider) - provides services such as internet access, internet transit, domain name registration, and hosting. ISP connects to customers using data transmission technology such as: -​ Dial-up -​ DSL (Digital Subscriber Line) -​ Cable modem -​ Wireless -​ FIber optic technology IP Address (Internet Protocol Address) - number that uniquely identifies each computer or device connected to the internet. Domain Name - Text version of IP address ​ Domain Name System (DNS) - is the method that the internet uses to store domain names and their corresponding IP addresses. ​ Top Level Domains - Last segment of the domain name. e.g. -​.com -​.org -​.net -​.fr Web Addresses (URL) - A uniform resource locator -​ The full address to a web page or file/program. Other Protocols: FTP (File Transfer Protocol) - used for interactive file transfer between systems. SMTP (Simple Mail Transfer Protocol) - for transfer of electronic messages and attachments. Intranet - private network accessible only by the organization’s members -​ Local or restricted communications network, especially a private network network created using World Wide Web Software. Data Communications History 1753 - Proposal submitted to a Scottish magazine to run a communication line between villages comprising 26 parallel wires representing each letter of the alphabet. (1833) Carl Freidrich Gauss -​ German mathematician and physicist; Regarded as one of the greatest mathematicians of all time. -​ Developed a system based on a 5x5 matrix representing 25 letters so messages could be sent in a single wire. (1834) Samuel Finley Breese Morse -​ American painter and inventor; Contributed to the invention of single-wire telegraph. -​ Invented the telegraph, the first successful data communication system that used binary coded electrical signals to transmit information. -​ Also developed Morse Code which uses dots and dashes. 1840 - Morse secured American patent for the telegraph. 1844 - The first telegraph line was established. First message conveyed - “What hath God wrought!” (1875) Alexander Graham Bell -​ Was a Scottish-born American inventor, scientist, and engineer -​ Credited with inventing the telephone. -​ Founded the American Telephone and Telegraph Company in 1885. (1899) Guglielmo Macorni -​ Italian inventor and radio pioneer -​ succeeded in sending radio (wireless) telegraph messages. 1957 Launch of Sputnik-1 - Earth’s first satellite -​ Launched into elliptical low orbit by the Soviet Union on October 4, 1957. 1963 Launch of Syncom-1 (February) -​ Intended to be the first geosynchronous satellite but was lost on the way due to electronics failure. 1963 Launch of Syncom-2 (July) -​ World’s first geosynchronous communications satellite -​ Experimental communications satellite placed over the Atlantic Ocean and Brazil. 1964 Launch of Syncom-3 (August) -​ Was the first geostationary satellite. -​ Provided live television coverage of the 1964 Olympic games in Tokyo. Diwata-1 - A.K.A PHIL Microsat-1 -​ First Philippine Satellite and Microsatellite launched. -​ Philippine Microsatellite launched to the ISS on MArch 23, 2016. Maya-1 - First Filipino Nanosatellite (June 2018 - November 2020). Maya-3 and Maya-4 (Oct 2021 - Aug 2022) -​ Filipino-made cube satellites; Returned to earth after 10-month mission. NETWORK Computer Network - two or more computers interconnected with one another for the purpose of sharing resources. Elements of Computer Network: ​ Protocols - rules and agreements on how the different parts of the network will operate. Protocol Stack - list or set of protocols used by the system ​ Data and Messages - information used or transmitted/received by the network. ​ Communications medium - interconnects the different devices in the network. ​ Devices - includes computers, routers, switches, bridges, hubs, etc. Classification of Computer Networks (according to geographic scope) ​ Personal Area Network (PAN)  ​ Local Area Network -​ Computers confined to one building or cluster of buildings. -​ Usually privately owned. ​ Metropolitan Area Network -​ Computers located within a city or cluster of cities. -​ Usually use facilities of telecom or network service providers. ​ Wide Area Network -​ Computers located outside a building or cluster of buildings. -​ Computers may be located between two or more cities, or between two or more countries. ​ Global Area Network -​ Computers located in different countries around the world. (Internet) Network Model Server - computer or system that provides resources, data, services or programs to other computers over a network Client - makes the request to the server Two Basic Network Model Peer to peer - All computers share their resources with all the other computers in the network. Dedicated client/server - one or more computers are assigned as a server and the rest of the computers are client (Comp Shop) Network Topology - refers to the appearance or the way the network is laid out. Physical Topology - Refers to the physical layout of the computers in a network. Logical Topology - Describes how data actually flows through the network. Most Basic Topologies ​ Point to point (P2P) - Two stations are connected. ​ Multipoint - Connects three or more stations. NETWORK TOPOLOGY Point to Point - Only two stations are connected by transmission medium. Pros: Very simple. Cons: Less stations can communicate with each other directly. Physical Mesh Topology - every station has a direct two point communication to every other station. Also known as fully connected. Pros: -​ Computer can communicate easily. -​ Robust (Data can have alternate routes). -​ Has more privacy and security. -​ Easier fault isolation. Cons: -​ More expensive and bulkier cabling lines -​ More communication ports are needed. -​ More cumbersome installation and reconnection. -​ Could have higher total cost of ownership. Physical Star Topology - Stations are connected directly to a centrally located device which acts like a multipoint connector. Central node is sometimes called the central control/switch. Pros: -​ If one computer fails, others can still communicate. -​ Requires less cable and communication ports than mesh. -​ Less expensive than mesh. -​ Easier to install than mesh. Cons: -​ If the central hub breaks down, all communications are down. -​ Less robust compared to mesh topology. -​ Often requires more cable than bus. Physical Bus Topology - All stations are connected to a single transmission medium. Also called multidrop, linear bus, horizontal bus. Pros: -​ Requires no special routing/circuit switching. -​ Not necessary to store and forward messages. -​ Requires less cable than other topologies. -​ Requires less communication ports than ring and mesh. Cons: -​ Computer could not communicate anytime (due to collision). -​ If cable breaks down, the entire network could be disrupted. -​ More difficult fault isolation. -​ Not suitable when stations are transmitting most of the time. Physical Ring Topology - All stations are connected in tandem to form a closed loop or circle Pros: -​ Requires less cable than mesh. -​ Requires less communication ports than mesh.  -​ Relatively easy to install -​ Could be less expensive than mesh Cons: -​ Delay is longer at non-adjacent stations. -​ If one cable breaks down, the entire network could be disrupted. -​ Requires more communication port than bus or star. Physical Tree Topology - A central root node (top level of hierarchy) is connected to one or more other nodes that are one level lower. Pros: -​ Leaf nodes can add one or more nodes in the hierarchical chain. Provides high scalability -​ The other nodes in the network are not affected if one of their nodes are damaged. -​ Provides easy maintenance and easy fault identification. -​ Can hold more nodes Cons: -​ Very difficult to configure compared to other topologies. -​ Presence of large number of nodes makes the network of topology a bit slower, -​ If the first level is erroneous, the next level will also have a problem. -​ Requires a large number of cables compared to star and ring. Hybrid - combines two or more complex traditional topologies to form a large, more complex topology. Pros: -​ Combines the benefits of traditional topologies used. Cons: -​ Combines the disadvantages of different topologies used.