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Computer Hardware Computers and components Basic Computer System Processor ALU CNTL ..... BUS Interconnections I/O module CONTROLLER MAIN MEMORY BUS ATTACHED DEVICE Computer Components CPU Cycle Increment Program Counter Start FETCH FETCH EXECUTE EXECUTE Halt Execution Cycle Instruction Sets Complex (CISC) or Reduced (RISC) INSTRUCTIONS ROM CNTL ALU ..... Measuring Processing Power Clock Speed Instruction Speed Word Length and Bus Width Speed of Arithmetic Instruction Set Pipelining Primary Storage Volatile DRAM SRAM Cache Nonvolatile ROM Measuring Storage (bytes) Kilobytes KB 1,000 B Text document Megabytes MB 1,000,KB Images Gigabytes GB 1,000 MB Hard disk drives Terabytes TB Trillions Data warehouse files Attached I/O Devices Secondary Storage DASD Tape Removable Electronic Storage Optical (etc.) devices Communication Devices Modems and Codecs LAN’s, Backbones and WAN’s Routers and other node devices Secondary Storage Devices Fixed Media hard disks RAID Removable Media diskette laser-servo diskette cartridge disks tape CD-ROM flash memory Attached Devices Hardware: device itself such as a disk or video display device. Electronics: controller that communicates with the device Software: device driver that is loaded into the computer operating system Local and Peripheral Bus Data Transfer: MAIN MEMORY DBUFFER A T A CHANNEL CPU CONTROLLER DASD I/O Controller (DASD) REGISTER PROCESSOR REGISTER REGISTER BUFFER Direct Access Storage Device (DASD) DASD Structure Read-Write Heads Cylinder/Track/Block Track Block (Sector) Cylinder Disk Organization Data Storage FAT (File Access Tables), Directories and Catalogs Update and Delete Fragmentation and reorganization Blocks, Headers and Interblock Gaps Hardware II General Purpose Computing Software primacy Applications are controlled by changing the instructions run by the computer, rather than by changing the hardware ASIC’s and Firmware Any program that can be written in software can also be burned onto a chip as a family of circuits Computer Classifications Size mainframe midrange microcomputer Function legacy mainframe server router client Mainframe (Legacy) Tuned for transaction processing Has channels to support very large numbers of attached devices Runs a mainframe operating system Tend to support legacy software Client/Server Architectures FAT CLIENT FAT SERVER SERVER PROCESSING CLIENT PROCESSING CENTRALIZED STAND-ALONE Client/Server Architecture An architecture in which the client (personal computer or workstation) is the requesting machine and the server is the supplying machine, both of which are connected via a network. Client/Server Architecture Client May do some or all of the processing Requests services from the network Server Contains data and may contain programs Server downloads information (applications or data) to the client for operation Client Use relatively inexpensive computer chips (Intel or Motorola) Have a single processor Optimized for user convenience Single user Limited numbers of attached devices Server Use inexpensive CPU chips Designed with redundant components Have large internal memory capacity May not need very fast CPU capability Three Tier Client/Server Any time Any place Any way Router Used to segment networks and prepare message packets for transmission Special purpose operating system to read and forward message packets May support firewall functions Support special purpose CPU chips and optimized network sysems Routers From A From B Input Buffer Input Buffer Input Buffer Processor Output Buffer Output Buffer Table of Addresses To C To D Central Architecture Client/Server Web Access