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Lecture 2

Lecture 2.doc

7 Pages

Information Technology
Course Code
ITEC 1000
Radu Campeanu

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Lecture 2 Computer Hardware and Software Hardware Components • Communications • Input Devices • output Devices • Secondary • Processing Devices Processing Device Centreal Processing Unit - CPu • Arithemtic/ logic unit ,control unit Arithmetic/ logic unit ALU • Perfroms math calculationa and logical comparisons Control Unit • accesses program instructions, decodes, coordinates data, out of ALU, sotrage prim and secondary Computer Memory • Registers - store small amount of data and instructions short time • Primary Storage - main memory stores data. operationf system programs and profgram execution • Secondary Storage - stores large amounts of data at exteneded perioods of time PRrocessing Charastericits and Functions Clock Speed • electroic pulse, predetermined rate that affects machine life • measuered in megaherts and gigaherts Physical Characteristics of the CPU • are collection of digital circuits imprinted on silicon wafers of chips Memory Characterisitcs and Functions Continued Types of memory • RAM - Random access memory - Temporary and volatile • ROM - Read only Memory - non volatile, provides permanent storage for data and instructions that do not change MultiProcessing • excution of two or more instructions at the same time increase • Multicore MicroProcessor - combines 2 ore more independent processors into a single computer task simutaneously • parallel computing - simultanerous excution of same task on multiple processors to be faster • Grid computing - collection of comps coordinated to solve problem low cost approach to parllel processing Secondary Stoarge and input and output Devices • Secondary Storage : • offers the advantages of non volatility, greater capactiy and greater economy • considerably slower then memory • Acess Methods - Sequential acess in order - Direct means retreived directly without sequence SASDS - DASD • Magnetic Tapes- storing backup for organizational data • Magnetic Disks - Direct Acess storage device enable fast data retreival used to respond quickly to co • Virtual Tape - store tech for less frequently data needed • dvd • Optical Discs - cannot be modified once been recorded • Solid State Secondary Storage Devices: • date stored in memory chips rather then magenetic of optical media • less fragile • Disadvantages: high cost per GB, lower capactiy compared to current hard drives • universal serial bus is EG USB Input Devices • Devices that used to input data: • personal comp input devices - data entry text charchter basic commands • speech regonition technolgy • digital cameras • magnetic stripe card • touch sensitive screens Output Devices • Display monitors- used to display the output form the computer • Plasma Display- uses thousands of smart cells (pixels) consisting of electrodes and neon and xenon gases that are electrically turned into plasma to emit light • LCD Displays - usees liquid crystals • Organic light emitiing diodes ( OLDEDS) - organic material sandwhiched between two conductors • printers - laser inket • audio player - organize music files Computer System Types • Can range from desktop or smaller portable computers to massive supercomputers that require housins in larger rooms Portable Computers • Handheld- single used that provide ease of portability due to size • laptop - designed for mobile users • Netbook - lightweight that weighs less then 5 pounds • Tablet - portable, lightweigh computers with no keyboard • Smartphone - combines the functionallity of phone camera web browser Nonportable Sinlge User Computers • Thin Client: low cost - centrall managed • Dekstop Computers- single user computer systems highly versatiele • Netbook: inexpensive used for internet • Workstations - powerful the personal comps small enough on a desktop Multiple - user computer Systems Server • used by many to perform specfic task, etc running network or internet apps Blade Server • Houses many comp motherboards • requiiers less phsycial space then traditional server farms Mainframe computer • large powerful shared by many users connected to the machine over a network Supercomputers • most powerful comps with fast processing speed and highest performance Software Signif
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