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In Chinese, a computer is popularly known as an " electrical brain", for the working process of a computer is similar to a human brain very much. In appearance, a microcomputer has three simple and apparent parts: the main frame, the keyboard and the monitor. In other words, if you own these parts, you would exactly have a computer. A computer system is composed of software and hardware in the light of its working mode. If we compare the hardware to a human body, then, the software would be soul. Just as a driver can't drive a car without driving skills or the car itself, you can't control a computer without controlling techniques or the computer itself. The controlling techniques are called software, while computers themselves and related devices are called hardware. The work of a computer is just making full use of various resources by software set in the computer, and directing the hardware to realize marvelous omnipotent functions. There are many types of microcomputers. Here, we will use an IBM Personal Computer (PC) to illustrate the primary components of a microcomputer. Other brands and models of microcomputers exhibit difference in appearance and operations. An IBM PC is shown in the figure. Its primary hardware components are the main frame, the monitor, the keyboard, and many peripherals such as the disk drive, hard disk, printer, and mouse, all of which are hardwired to the main frame. The main frame is the heart of a microcomputer system. It contains the Central Processing Unit (CPU), a chip that controls the major operations of the computer and the main memory. The typical secondary storage medium of a microcomputer is the floppy and hard disks. A floppy disk, or diskette, is a thin circular piece of flexible polyester coated with a magnetic material. The data are recorded on a series of concentric circles called tracks. The access mechanism steps from track to track, reading or writing one track at a time. A track is subdivided into sectors. To distinguish the sectors, they are sequentially addressed by natural numbers 0,1,2and so on .A sector is a primitive access unit.Most microcomputers use floppy diskettes of 5 1/4 inches and 3 1/2inches in diameter. The following figure shows a 3 1/2 inches floppy diskette. Hard disks, or fixed disks, can be either fixed in the mainframe as a part of the internal hard disks reside permanently within the microcomputer and are removed only for servicing or replacement. External hard disks can be purchased alone and then attached to the microcomputer with cables; they are used for backing up large amounts of data or for additional storage capacity. Hard disks provide tremendous storage capacities ranging from hundreds of megabytes to several gigabytes. A keyboard is a requisite hardware device of a computer. It is an input device most in use, and a dialogue tool between a man and a computer. We can input data needed to be processed or preserved by a computer via a keyboard. A typical includes a group of standard keys set in the center of the keyboard, many function keys and several additional keys. Function and additional keys have different roles in different software. Another popular input device is mouse. The mouse is a small, handheld object that is pushed around a desktop to move the cursor on the screen or to select choices from menus displayed on the screen. A mouse is essentially a pointing device that allows the user to do many operations more quickly than he could with the keyboard alone. The monitor is an essential output device of a microcomputer. Monitors, also known as video display terminals (VDTs), resemble television screens, and may be either monochrome or color. A monochrome monitor displays only one color on the screen. It is possible white or more eyepleasing green. While color monitors usually offer a wide selection of display colors. The printer is the most commonly used output device after the monitor. Printers can create a permanent paper copy of results generated by the program being run on the computer. These printouts are sometimes referred to as hard copy. Printers can also generate listings of programs and graphic images. Three types of printers are available: wire printers, ink jet printers and laser printers.
微型計算機的奇妙結構 在中文里，計算機有一個人所共知的雅號：“電腦”。這是因為計算機的工作過程與人的大腦思維過程極為相似。
從外表上看，微型計算機有簡單而鮮明的三部分：主機、鍵盤和監(jiān)視器。換句話說，只要你擁有了這三部分，你就確實擁有一臺微型計算機。從計算機的工作過程看，計算機系統(tǒng)是由軟件和硬件組成的。如果你將硬件比作人的軀體，那么，軟件就好比人的靈魂。 正像沒有汽車或者沒有汽車駕駛技術，司機就不能駕駛汽車一樣，沒有計算機或者沒有控制計算機的技術，人就不能操縱計算機。這些控制計算機的技術被叫作軟件，計算機及其各種設備本身被叫作硬件。 計算機的工作就是通過計算機的軟件組，充分利用計算機的各種資源，并指揮硬件實現(xiàn)無所不能的奇妙用途。 微型計算機的主要組成部分 微型計算機種類繁多。在這里，我們用IBM個人計算機（PC）來解釋微型計算機的主要組成部分。其他品牌和型號的微機在外貌和操作上各有不同。一臺IBM PC計算機如圖所示：它的主要硬件成分是主機、監(jiān)視器、鍵盤以及許多與主機相連的外圍設備，如磁盤驅動器、硬盤、打印機、鼠標。主機是微機系統(tǒng)的核心，它包括中央處理單元（CPU）和主存，CPU是一塊控制計算機主要操作的芯片。 軟盤和硬盤 微型計算機的典型的輔助存儲介質是軟盤和硬盤。軟盤是一個表面附有磁性材料的柔性的聚酯材料做成的圓圓的薄片。數(shù)據(jù)被記錄在一些被稱為磁道的同心圓上，存取裝置讀寫磁道的過程是從一個磁道到另一個磁道，一次只讀寫一個磁道。磁道又分為扇區(qū)，為了區(qū)分這些扇區(qū)，用0、1、2等給扇區(qū)按順序編上地址號，一個扇區(qū)是一個基本的存取單位。 大多數(shù)的微機使用5 1/4和3 1/2英寸的軟盤，下圖示的是一張3 1/2英寸的軟盤。 硬盤，又稱固定盤，它既可以固定在主機箱內成為微機內部設計的一部分，也可以是獨立的外部單元。內部硬盤永久性地安置在微機內，只有需維修或更換時才取出。外部硬盤可以獨立購買，通過電纜線與微機相連；它的用處是備份大量的數(shù)據(jù)或增加存儲容量。硬盤的存儲容量從幾百兆字節(jié)不等。 鍵盤和鼠標 鍵盤是計算機的一具必要的硬件設備，也是最常用的一種輸入設備，是人與計算機的對話工具。我們可以通過鍵盤把數(shù)據(jù)、資料等需要計算機處理或保存的信息送入計算機。 一個典型的鍵盤包括一組位于鍵盤中間的標準鍵、許多功能鍵和一些附加鍵。功能鍵和附加鍵在不同的軟件中有不同的軟件中有不同的作用。 另一種常用的輸入設備是鼠標。鼠標是一個可以用手在桌面上推動的小東西，通過它可以在屏幕上移動光標或者選中菜單上的某項功能。鼠標是一個必要的外部設備，它可以使用戶以比僅使用鍵盤快得多的速度完成許多操作。 顯示器 顯示器是微機必需的輸出設備。顯示器類似于電視屏幕，也被稱為視頻顯示終端（VDTs），有單色顯示器和彩色顯示器。單色顯示器屏幕上僅顯示一種顏色，這可能是白色或是一種更悅目的綠色。彩色顯示器通常提供許多種可供選擇的單色。打印機 打印機是除顯示器外最常用的輸出設備。打印機可以將程序運行的結果打印出來，從而成為永久的紙拷貝。這種打印輸出有時也被稱為硬拷貝。打印機也可以打印程序列表和圖形圖片。有三種類型的打印機：外打式打印機、噴墨打印機和激光打印機。 |
