What a microcomputer system consists of
A microcomputer system consists of two major parts: a hardware system and a software system.
The hardware system of a microcomputer generally consists of the CPU, motherboard, memory, display card, hard disk, power supply and monitor, keyboard, mouse, etc. installed in the main box. In order to make the microcomputer with multimedia processing capabilities, can also be configured with multimedia peripherals such as optical drives and sound cards. If you need to network and send faxes, you can also configure the modem, network card, fax card and so on. The software system of the microcomputer consists of system software and application software.
Microcomputer, is a computer with a microprocessor as the CPU. Composed of large-scale integrated circuits, smaller electronic computers. Composed of microprocessor (core), memory chips, input and output chips, system buses and so on. Characterized by small size, flexibility, inexpensive and easy to use. A common characteristic of this type of computer is that it occupies a very small physical space.
Microcomputer mainframe components:
1, the central processing unit (CPU): is composed of one or several pieces of large-scale integrated circuits with the operator and controller functions of the central processor components.
2, the main memory: is the storage of instructions and data, and can be directly random access by the central processor, usually divided into random memory (RAM) and read-only memory (ROM).
3, I / O interface circuit: the interface to connect the input / output devices, such as connecting the keyboard, mouse, monitor, etc. data line interface.
4, the system bus: the bus system for connection between devices within the host, such as the central processor CPU and the main memory (memory) connection.
What are the components of a microcomputer?
1, microcomputer is mainly composed of hardware systems and software systems.
2, microcomputer hardware system is mainly composed of the following parts: microprocessor or central processing unit (CPU), internal memory (referred to as memory), input and output interfaces (referred to as interface) and the system bus.
(1) CPU, CPU is a complex electronic logic components, it contains the early computer operators, controllers and other functions, can perform arithmetic, logic and control operations.
(2) Memory, as the name suggests, the so-called memory refers to the internal storage of the microcomputer.
(3) System bus, the so-called bus is a set of communication lines used to transfer information. By Figure 2.1 you can see the system bus will constitute the various components of the microcomputer connected together, realizing the microcomputer within the exchange of information between the various components.
(4) interface, microcomputers are widely used in various sectors and fields, connected to a variety of external devices.
3, microcomputer software system mainly includes system software and application software two categories.
(1) system software, system software is used to constitute a microcomputer hardware, such as CPU, memory, a variety of peripherals for management and coordination, so that they work efficiently and in an organized manner.
(2) application software, application software is for different applications, the realization of the user’s requirements of the functionality of the software, for example, Internet outlets on the Web page, the departments of the MIS program, CIMS in the application software and the production process monitoring and control program.
1, microcomputer referred to as “microcomputer”, “microcomputer”, because it has some of the functions of the human brain, so it is also called “microcomputer”. Microcomputer is composed of large-scale integrated circuits, smaller electronic computers. It is based on a microprocessor, with internal memory and input/output (I/0) interface circuits and the corresponding auxiliary circuits and the composition of the bare metal.
2, the working process of the microcomputer
CPU simple arithmetic or logical operations, or from the storage device to take the number of data stored in the storage device, or by the interface to take the number of or to the interface to send the number of these are some of the basic actions, also known as the operation of the CPU.
3. Most of the equipment of a minicomputer is tightly packed in a separate chassis, while some may be placed near and connected to the chassis, such as a monitor, keyboard, mouse, and so on. Generally, a minicomputer is sized so that it can easily fit on most desktops. In contrast, larger computers like minicomputers, mainframe computers, and supercomputers can take up part of a cabinet or an entire room.
What are the components of the hardware system of a microcomputer?
The basic components of a computer hardware system (the five major components): the operator, the controller, the memory, the input devices, and the output devices.
The operator and controller are collectively called the central processing unit (CPU).
Memory is divided into two categories: internal memory and external memory.
The CPU, the internal memory, and the interface to the input and output devices are collectively referred to as the mainframe. The mainframe of a microcomputer is integrated on the motherboard.
External memory, input devices and output devices are collectively called external devices.
Central Processing Unit (CPU)
The central processing unit of a computer, also known as the CPU, is the core part of a computer. It is mainly composed of an operator and a controller.
Operator: a component that realizes arithmetic and logical operations.
Controller: the command system of the computer. The controller accesses the memory through the address, takes out the instruction from the memory, analyzes it by the decoder, produces the corresponding operation control signal according to the result of the instruction analysis to act on the other parts, and makes the parts under the control of the controller to coordinate the work in an orderly manner.
Instruction: command the computer to carry out a variety of operations.
Instruction system: a computer set of all the instructions.
The four basic operations to execute an instruction:
The CPU of a microcomputer, also known as a microprocessor, is rapidly renewed:
4004→8008→8080→8088→80286→80386→80486→80586→Pentium Ⅱ→Pentium Ⅲ→Pentium Ⅳ → …
The performance index of CPU is determined by the clock frequency (main frequency) and word length.
The main frequency is the clock frequency of the CPU. The higher the main frequency, the faster the computer’s computing speed. Pentium III main frequency can be up to 866MHz or more, and Pentium IV can be up to 2.6GHz and 2.8GHz.
Word length is the length of a word. The longer the word length, the greater the range of representation of the number, the higher the precision of the operation, and in the same clock frequency, the faster the operation speed. Microcomputer word length has gone through four generations of 4-bit → 8-bit → 32-bit → 64-bit changes.
Computer storage mechanism
Memory is a memory component used to store all the data and programs in the computer, its basic function is to store (write) or fetch (read) information at a specified address.
Memory in a computer can be divided into two categories: one is internal memory, referred to as memory or main memory; the other is external memory (auxiliary memory), referred to as external memory or auxiliary memory.
Memory consists of a number of storage units, each of which has an address through which the computer reads and writes to the storage unit.
The number of bytes contained in a memory is called the storage capacity, and is measured in B, KB, MB, GB, TB, etc.
1B=8bits (1 byte=8 bits)
Computer’s Storage Mechanism – Memory
Memory: Used to store programs or data currently in use, or to be used at any time, including ROM and RAM.Main features: fast access speed, small capacity, expensive.
ROM: read-only memory. Characteristics: can only read, can not write; power failure will not lose information. Mainly used to store a fixed and unchanging basic input and output programs.
RAM: Random Access Memory. Characteristics: readable and writable; but all information is lost after power failure.
The size of a microcomputer’s memory capacity is generally the size of the RAM. Currently, the common memory configuration for microcomputers is 64MB, 128MB, 256MB or 512MB.
Computer storage mechanism-external memory
External memory: used to store temporarily unused or need to save the program or data. When you need to use the information in the external memory, it must be transferred to RAM to be executed and processed by the CPU. Main features: slow access speed, large capacity, cheap.
Microcomputer external memory generally have: floppy disk, hard disk and CD-ROM.
Floppy disk memory (referred to as floppy disk): by the floppy disk, floppy disk drive and floppy disk drive card. Microcomputer commonly used 3.5-inch floppy disk, capacity 1.44MB. note: the write-protect port on the floppy disk is set to protect the data on the floppy disk device.
The information stored on a floppy disk is organized by track and sector. Tracks are concentric circles, each with a different perimeter, but storing equal amounts of data. Each track is divided into a number of sectors, each sector can store a number of bytes. The number of sectors and bytes is determined by the formatting program.
Formatting: The process of dividing a disk into tracks and sectors and writing address labels for each sector. A formatted disk produces four areas: the boot area, the file allocation table area, the file directory area, and the data area.
Write-protect notch: controls read and write operations on a floppy disk.
Capacity calculation of a floppy disk: number of bytes/per sector x number of sectors/per track x number of tracks/per side x number of sides
Hard disk memory (referred to as hard disk): consists of a hard disk and a hard disk drive. The hard disk is organized to store information in a format of cylindrical surfaces, header numbers and sector numbers. Columnar surface by a group of disks of the same track in the longitudinal direction formed by the concentric garden columnar surface, the columnar surface of the individual tracks and sectors of the same division with the disk. The hard disk is enclosed in a metal body, and the location of data on the hard disk is determined by three parameters: the plenum number, the head number and the sector number. Hard disks commonly used in microcomputers include 10GB, 20G, 30G, 40G, 60G, 80G, 100G, 120G, and many others.
Optical disk memory: consists of optical disk and optical disk drive. Currently there are three main types of optical discs: read-only optical discs (CD-ROM), write-once optical discs and erasable optical discs. 5.25-inch CD-ROM capacity of 650MB to 1GB.
Computer’s input devices
Input device is a device that inputs information (programs, data, sound, text, graphics, images, etc.) into the computer. Common input devices in microcomputers are: keyboards, mice, graphic scanners, touch screens, bar code inputs, light pens, etc. External memory is also an input device. [Diagram]
The mouse can be categorized according to its structure: electromechanical and photoelectric mouse.
Output devices of computers
The main output devices of computers are monitors, printers and plotters. External memory is also an output device.
Monitors have a variety of cathode ray tube monitors, liquid crystal displays, and plasma displays, which are further divided into 14-inch, 15-inch, 17-inch, and 17-inch flat. The content on the monitor consists of pixels, the sum of pixels is the resolution; common high resolution: 640 * 480/1024 * 768/1280 * 1024; the higher the resolution, the better its clarity. The interface between the monitor and the host is the graphics card, and common graphics cards are VGA, SVGA, etc. The color graphics card supports the number of colors. The number of colors supported by the color graphics card is an important indicator of the graphics card, mainly depends on the size of the RAM memory.
Example: the resolution is 320×200, each pixel point is required to display 4 colors, then by 22=4 can be seen by each pixel point color occupies 2bit, a total of 2×320×200=16000B of video memory.
Common printers are: pin printers, laser printers and inkjet printers.
Other parts of the computer
Motherboard: microcomputer using a “building block” architecture, the motherboard is a printed circuit board, there are a number of rectangular slots, CPU, memory, graphics cards, multifunction cards can be inserted on the motherboard. Multi-function cards have serial ports (for connecting a mouse) and parallel ports (for connecting peripherals such as printers). Also sound bar cards, video cards, modems, etc. will be plugged into the motherboard.
Interface: input/output interface circuits are indispensable components for transforming information and realizing buffering functions between microprocessors and external devices.
Bus (BUS) is a set of public signal lines connecting the various components of the microcomputer between the computer is to transmit data and information in the public channel. According to the different information transmitted, the bus is divided into address bus (AB), data bus (DB) and control bus (CB).