What is a computer? - A machine that: - Counts. - Does Arithmetic (Addition, Subtraction, Multiplication, and Division) in binary system. - Stores numbers. - Retrieves numbers. Units of Measurement - The bit (Binary digit). - The bit (Binary digit) is a basic unit of information used in computing and digital communications. A binary digit can have only one of two values, and may be physically represented with a two-state device. These state values are most commonly represented as either a 0 or 1. - The two values of a binary digit can also be interpreted as logical values (true/false, yes/no), algebraic signs (+/ ), activation states (on/off), or any other two-valued attribute. - The byte. - An eight bit counter is called a Byte. - A Byte may represent up to 256 numbers; from 0 to 255. - A Byte is long enough it may represent any character alphabetic (both capital and low), number (from 0 through 0), any special character ( *, & @, etc.), and control character (New-Line, Tab, etc.) - The kilobyte (Kb). - 1024 Bytes. (2 10 ) - The megabyte (Mb). - 1,048,576 Bytes (2 20 ) - The gigabyte (Gb). - 1,073,741,834 Bytes (2 30 ) - Today is the most common unit of measurement, for most devices (Cell-Phones, Laptops, Tablets, etc.) capacities (Both volatile memory and permanent hard drive) are measured in gigabytes. - The terabyte (Tb). - 1,099,511,627,776 Bytes (2 40 )
Concepts ASCII Table Data: It s information collected and stored in a computer. Data can be facts, a list of names, numeric information, pictures, videos, etc. Examples are: - An email. - A Contacts list. - An attendance list. - A Bank Statement. The basic Data unit is the field, a collection of related fields are called a Record, and a collection of records is called a File.
Fields Field Name Record File: Product Inventory Program: It s a group of instructions that perform a task (or many tasks) in a computer. Depending on their use computer programs are divided into: - System Programs. - Application Programs. System Programs: are programs that control hardware and software. Example of System Programs are:
Operating Systems. Communication software. An Operating System (OS) is mainly an interface between the user and the hardware. Example of OS are: Application Programs: Also called Programs, or Applications, or simply Apps are designed to perform a specific task. Example of Application Programs are: Word Processors. Games. Email programs. Social Media programs. Calendars. Contacts. Music Apps. Hardware: The concept refers to all physical components of a computer; CPU, Motherboard, LAN Card, Monitor, Keyboard, etc.
Software: Are all programs installed in a computer. As mentioned earlier computer programs are divided into: - System Programs. - Application Programs. Firmware: Is a specific class of computer software that provides the low-level control for the device's specific hardware.
Computer basic operation Input Process Output Storage Most basic flowchart. As an input is received, a process is performed on that input data, producing an output data.
Input Device CPU CU (Control Unit) Registers ALU (Arithmetic Output Device Main Memory The instructions - Programs consists of instructions executed one by one in sequence. - The main function of the processor is to execute instructions. - An instruction is the basic operation done by a computer. - Any program we run is broken down into a very large number of instructions; sometimes millions or billions of instructions. - The CPU executes these instructions one bye one. - A source program (i.e. C Language) does not run directly on the hardware. - A high-level language like C, gets compiled. - The compiler produces an executable program -machine language,- which is made of 1s and 0s. - The machine language is executed by the CPU. It runs directly on the hardware.
Concepts Input Device: Is any computer hardware that captures data of any form, and sends it to the CPU for processing and storing PC Input Devices
Concepts Output Device: Is any computer hardware that send data to another device or user Computer Output Devices
Types of Computers Computers can be generally classified by different parameters: size, function, use, etc. On this slide they are presented by size. Supercomputers. Mainframes. Minicomputers. Personal Computer (PC). Desktop. Laptop. Tablets Smartphones, smartbooks. Programable calculators. Game consoles. Supercomputers Supercomputers perform at the highest speed; therefore the are the fastest computers in existence. Uses: Weather Prediction. Space travel calculation. Molecular dynamic simulations. Sequence analysis and human genome.
Mainframes Computers with large capacity (Disks, Memory, etc.), and more processing power than servers, minis, or PC s. Used primarily by large corporations such as banks- to manipulate large amounts of data. While supercomputers focus on fast number crunching; mainframes focus on fast and reliable transaction processing. Uses: Used by large corporations. Banks. Census. Make use of virtualization (VM s). Highly available. Many users at one time. Superminis Less powerful than mainframes, but capable of supporting many users/many applications: Medium sized corporations, hospitals, labs, etc. Used in the last part of the 20 th century; they have been replaced by networks using Server/Client approach. Uses: Mainly commercial use. Invoice/Billing. Schools/Teaching. Medicine/Record keeping Many users/many applications. Many people accessing the same data at one time. Many applications running concurrently.
Microcomputers Also known as Personal Computers (PC s) have a wide range of forms depending on their use. Mainly used with one operating system: Microsoft Windows; although others such as Unix, Linux and Apple IOS are also available Uses: Virtually everything. In networks (LANs) they replaced superminis. Many uses/applications. Other networks such as WAN include the Internet.
The Atom
Ohm's law States that the current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, [1] one arrives at the usual mathematical equation that describes this relationship