All kinds of application software need some common basic operations, such as input device Get data from output device Send data to External storage Write data, read data from external storage, routine management of data, etc. These basic work should also be completed by a series of instructions. These instructions are collectively organized to form special software to support the operation of application software, which is called system software. Generally speaking, system software includes operating system And a series of basic tools (such as compiler , database management, storage Formatting, file system management, users Authentication , drive management, network connections And other tools) to support computer system The part of software that runs normally and realizes user operation. The system software is generally computer system It can also be installed separately as required. The main features of the system software are:
*It is very strong with the hardware Interactivity *Be able to resource sharing Conduct scheduling management *It can solve the coordination problems in concurrent operation processing
*Of which data structure Complex, diversified external interfaces, easy for users to use repeatedly The system software provides the application software with the above basic function At the same time, hardware management is also carried out, so that different application software running at the same time or successively on a computer can use hardware equipment in an orderly manner. For example, two application softwares need to store and modify data to the hard disk. If there is no coordination and management organization to demarcate areas for them, it will inevitably lead to mutual destruction of each other's data. [1] yes Representativeness The system software of is: The operating system manages the hardware devices of the computer so that the application software can use these devices conveniently and efficiently. The common ones on microcomputer are: DOS 、WINDOWS、UNIX、 OS/2 Etc. The most important and basic thing in computer software is operating system （OS）。 It is the lowest level software, which controls the programs run by all computers and manages the resources of the whole computer. It is the computer bare pager And application program And the bridge between users. Without it, users cannot use certain software or programs. operating system yes computer system From the perspective of resources, it has processor , memory management device management 、 file management 4 functions. Common systems are DOS Operating system, WINDOWS operating system UNIX operating system and Linux , Netware and other operating systems. [2] Compiling software CPU Executing each instruction only completes a very simple operation. A system software or application software is composed of thousands or even hundreds of millions of instructions. Writing software directly with basic instructions is an extremely arduous and difficult task. Computers can only recognize and execute directly machine language , so run on your computer high-level language The program must be equipped with programming language Translator The translator itself is a group of programs, and different high-level languages have corresponding translators. Language processor Such as assembly language assembler, C language compiler, connector, etc. In order to improve efficiency, people stipulate a new set of instructions, called high-level language, in which each instruction completes an operation, which is simple and basic relative to the overall function of the software, and complex relative to a minor operation of the CPU. Write programs in this high-level language (called source program ）It's like using Precast slab Instead of bricks Building a house , the efficiency is much higher. However, the CPU cannot directly execute these new instructions. It needs to write a software that is specifically used to translate each instruction in the source program into a series of basic instructions (also called machine language) that the CPU can accept, so that the source program can be converted into a program that can run on the computer. The software that completes this translation is called high-level language compiler software, which is usually classified as system software. At present, the commonly used high-level languages are VB , C++, JAVA, etc. They have their own characteristics and are suitable for writing a certain type of program. They all have their own compilation software. [1] Database management system Organize and dynamically store a large amount of data, so that people can use these data conveniently and efficiently. Database management system is a kind of manipulation and Management database Large scale software for establishing, using and maintaining databases. Foxpro，Access， Oracle ，Sybase， DB2 And Informix are database system 。 System auxiliary processing program is also called "software development" development tool ”、“ Support software ”、“ software tool ”, mainly including Edit program 、 Debugger , equipment and Connector Debugging procedure. 
