计算机专业英语阅读1.docVIP

第二单元 ORGANIZATION OF COMPUTER SYSTEM COMPONENT Now that weve examined what is a computer,lets look again at our computer definition:A computer is a fast and accurate symbol manipulation system that is organized at accept,store,and process data and produce output results under the direction of a stored program of instructions.This section explains why a computer is a system and how a computer system is organized. Key Element in this system include memory,input processing,and output devices.Lets examine each component of the system in more detail. INPUT DEVICES.Computer systems use many devices for input purpose.some input devices allow direct human/machine communication.while some first require data to be recorded on an input medium such as a magnetizable materiel.Devices that read data magnetically recorded on specially coated plastic tapes or flexible or floppy plastic disks are popular.The keyboard of a workstation connected directly to...or onlineto... a computer is an example of a direct input device.Additional direct input device include the mouse,input pen,touch screen,and mocrophone.Regardless of the type of device used,all are components for interpretation and communication between people and computer system. CENTRAL PROCESSING UNIT.The heart of and computer system is the central processing unit(CPU). There are three main sections found in the CPU of a typical personal computer system:The primary storage section,The arithmetic-logic section,and The control section.But these three sections arent unique to personal computer:They are found in CPUs of all sizes. OUTPUT DEVICES.Lide input units, output devices are instruments of interpretation and communication between humans and computer systems of all sizes.These devices take output results from the CPU in machine-coded form and convert them into a form that can be used (a) by people (e.g. a printed and/or displayed report) or (b) as machine input in ano