Chapter 1 Computer Basics

What is a Computer? Functional definitions (45%) Humorous definitions (5%) Academic definitions (45%) Other (5%)

Functional Definitions “A computer is a machine that facilitates many tasks, like word processing, web searching, etc. It is a tool.” “A computer is a machine used for many different things; multimedia, word- processing, & research.” “A computer is a machine that’s purpose is to make the work of humans easier, and more time efficient.”

Humorous Definitions “A computer is a machine that does what the operator tells it to do.” “A computer is a thing that always crashes right when you’re in the middle of an important assignment.” “A porn box.”

Humorous? Definitions “A machine we, as society, have come to base our lives upon. It confuses many, and frustrates more. It can do more than man, yet men built it. They suck, though I learn to live with them.”

Academic Definitions “A computer is something that receives and processes information and then puts out responses.” A computer is an electronic device that stores information and/or processes that information.” “A computer is a piece of machinery used to perform some type of calculation or task through a series of inputs and outputs.”

Academic Definitions Classical academic definition: “A computer is any device that receives input, processes that input, and produces output.” “A computer is any device that receives input, processes that input, and produces output.” In everyday life, this is too broad Computers are electronic devices that primarily use binary logic and integrated circuitry Computers are electronic devices that primarily use binary logic and integrated circuitry They carry out a given task by executing a certain series of steps, according to programming, either in hardware or software They carry out a given task by executing a certain series of steps, according to programming, either in hardware or software They have a clearly distinguishable central processing unit which handles the computation They have a clearly distinguishable central processing unit which handles the computation

Computers For most of what we talk about in this course, we’ll assume we’re talking about desktops The primary division in a desktop computer is hardware vs. software Hardware: The physical (tangible) devices or components that make up a computer system. Software: The programs (intangible sequences of instructions) that a computer system runs. The easiest way to tell the difference between hardware and software is to kick it. If it hurts your toe, it's hardware. -- Carl Farrell

A Typical Desktop Computer

The System Unit Houses the following: CPU (Central Processing Unit) CPU (Central Processing Unit) RAM (main memory), RAM (main memory), hard disk drives (e.g. C: drive) hard disk drives (e.g. C: drive) floppy drives (e.g. A: drive) floppy drives (e.g. A: drive) other drives (e.g. CD-ROM, DVD) other drives (e.g. CD-ROM, DVD) also holds slots for various cards (e.g. network card, sound card, video card). also holds slots for various cards (e.g. network card, sound card, video card). Do not call it a “system cabinet”

Peripherals A peripheral is any part of the computer external to the system unit Peripherals allow communication between external sources (e.g. you) and your computer. Examples: mouse, keyboard, monitor, speakers, digital camera, printer, scanner, etc. mouse, keyboard, monitor, speakers, digital camera, printer, scanner, etc.

Types of Computers Supercomputers can cost millions of dollars can cost millions of dollars perform trillions of operations per second perform trillions of operations per second may have hundreds of thousands of CPUs may have hundreds of thousands of CPUsMainframes Central computing units used by organizations (e.g. banks, airlines, insurance companies). Central computing units used by organizations (e.g. banks, airlines, insurance companies). Can support 100s of users connected via terminals. Can support 100s of users connected via terminals.Workstations Scientific, engineering, mathematical workhorses. Scientific, engineering, mathematical workhorses. Targeted toward a special-purpose task (e.g. numerical analysis, graphics design). Targeted toward a special-purpose task (e.g. numerical analysis, graphics design).Microcomputers PCs (Personal Computers) = desktop computers, PDAs (Personal Digital Assistants), Laptops & Notebooks, Tablet PCs. PCs (Personal Computers) = desktop computers, PDAs (Personal Digital Assistants), Laptops & Notebooks, Tablet PCs. Microcontrollers (Embedded Systems) Computers embedded in "ordinary" systems. Computers embedded in "ordinary" systems. Control your TV, telephone, microwave, CD-Player, car airbags,.... Control your TV, telephone, microwave, CD-Player, car airbags,....

What is Computing? Computing is a 4-step sequence that turns raw data into useful information: Input Input Processing Processing Storage (sometimes omitted) Storage (sometimes omitted) Output Output

Input Input is when information is received from an outside source, such as: A device: keyboard, mouse, modem, network card. Memory: DVD movie, file on hard drive, CD

Processing Done in the CPU (Central Processing Unit) The computer executes millions (or billions) of very simple instructions per second. Examples include: FETCH a memory element. FETCH a memory element. FETCH another memory element. FETCH another memory element. ADD these memory elements together. ADD these memory elements together. STORE the result to memory. STORE the result to memory. These instructions form the computer’s program. These instructions form the computer’s program. Firmware: unchangeable instructions that are executed when computer first boots up. These instructions are located in ROM (read-only memory), and contain basic hardware sequences which cannot be altered because they are permanently etched into a physical chip Software: Applications (e.g. Word, Excel, Internet Explorer) Applications (e.g. Word, Excel, Internet Explorer) System Software / Operating Systems (e.g. Any version of Windows) System Software / Operating Systems (e.g. Any version of Windows)

Processing pt 2 The processor follows this basic cycle: FETCH FETCH DECODE DECODE EXECUTE EXECUTE STORE STORE The cycle starts again when the next command is fetched.

Storage Information can be stored in volatile or non-volatile memory. Volatile memory (basically RAM) is fast but if the power goes, all the data is lost. Volatile memory (basically RAM) is fast but if the power goes, all the data is lost. Non-volatile memory is slower, but the data persists even after you power down your computer. Examples: DVD disks, CDs, floppy disks, hard drives Non-volatile memory is slower, but the data persists even after you power down your computer. Examples: DVD disks, CDs, floppy disks, hard drives

Output Output occurs any time information is passed from the computer to an external device Examples: A file prints on the printer A file prints on the printer A page is displayed on the monitor A page is displayed on the monitor A signal is sent over a modem or network card A signal is sent over a modem or network card

The Book vs. Me System Cabinet??? 10.8 Gig = $120 in GB = $120 in GB = $75 in GB = $59 in 2005 Building your own computer IS cheaper… Until you factor in bad parts, repairs, system conflicts, your time, and frustration Until you factor in bad parts, repairs, system conflicts, your time, and frustration