COMPUTER OPERATION SYSTEM 2.1SUMMERY OF PERATING SYSTEM

Operation systems have developed over the past thirty years for two main purposes,First.they provide a convenient enviroment for the development and execution of programs. Second.operation systems attampt to schedule computational activities to ensure good performance of the computation.在过去30年间操作系统朝着两个主要目标发展，第一，为程序开发和执行提供一个方便的环境，第二操作系统试图对计算机任务进行调度以确保计算机性能良好。As we have stared,operations are normally unique to their manufactures and the hardware in which they are run,Generally.when a new computer system is installed.operation sofeware that can effectively support their processing activities.如前所述，操作系统对于其生产厂家与其运行的硬件通常是特有的，一般来讲，安装一台新的计算机系统的同时，也有购买了与该硬件相对应的操作系统，用户需要有效地支持其处理工作的可靠的操作系统软件，Though operational software varies with manufacturers,it has similar characteristic.Modern hardware,decause of its sophisication,require that operating systems meet certain specific standards,For example.considering the present state of the field.an operation system must support some from online processing,Functions normally associated with operational software are:尽管各厂家的操作系统软件各不相同，但是特性类似，对于现代硬件系统，由于复杂性，因此要求其操作系统满足某些特定的标准，例如:考虑到该领域的现状，操作系统必须支持某种形式的联机处理，通常，与操作系统软件相关的功能有：(1)Job mangement.作业管理(2)Resource management.资源管理(3)Control I/O operations.I/O操作控制(4)Erro recovery.错误排除(5)Memory management.内存管理1.job management作业管理A very important responsibility of any operational software is the scheduling of job management function,The operation system sets up the order in which programs are processed,and defines the sequence in which partocular jobs are execution,The term "job queue" is oftem used of describe the series of jobs awaiting execution.The operation system weighs a variety of factors in creationg the job queue.These include which jobs are currently being processed.the system's resources being used.which resources will be needed to handle upcoming programs.the priority of the job compared to other tasks.and ang special processing requirements to which the system must respond.操作系统的一个非常重要的职责是对计算机系统要处理的作业进行调度。这是作业系统功能的主要任务之一。操作系统建立了程序处理的顺序，并确定了具体的作业执行的序列，术语“作业队列” 常用于描述等待执行的作业序列，操作系认同在排列作业队列时权衡各方面因素，包括当前正在处理的作业，这在使用的资源，即将处理程序所需要的资源，与其他任务相比该作业的优先级，以及系统必须响应的任何特殊处理要求。The operational software must be able to assess these factors and control the order in which jobs are processed.操作系统软件应能评估这些因素并控制作业处理的顺序。Batch systems allowed aotomatic job sequeencing by a resident monitor and imporved the overall utilization of the computer greatly.The computer no longer had to wait to wait for human operation.CPuU utilization was still low.however ,because of the low speed of the I/O devices relative to the CPU.Offine operation of slow devices was tried.BUffering was another approach to improving system performance by overlapping the input,output,and another computation of a single job,finally.spooling allowed the CPU to overlap the input of one job with the computation and output of other jobs.壁橱里通过一个驻留监控程序是的作业的自动排,同时也大大提升了计算机的整体利用率。计算机不再需要等待人工操作，但是用于I/O 设备的速度相对于CPu任然很低，因此Cpu的利用率很低，于是就尝试了低速设备的脱机操作，缓冲技术是另一种改善系统性能的方法，他是通过将单个作业的输入，输出，和计算机的重叠操作，最终实现，假脱机技术使得CPU将一个作业的输入同其他作业的计算和输出重叠操作。Spooling also provides a pool of jobs which have been read and are waiting to be run,The job pool supports the concept of multiprogramming,with multiprogramming,servel jobs are kept in memory at one time.The CPU is switched back and forth between them in order to increase CPU utilization and to decrease the total real time needed to execute a job.假脱机操作同时还提供了一个作业池，其他的作业已读出并等待运行，这个作业池多道程序设计的概念。在多道程序下，几个作业可同时保持内存中，Cpu在他们之间来回服务，以便提高CPU将一个作业的同其他作业的计算和输出重叠操作。Multiprogramming, which was developed to improve performance, also allows timw sharing.Time shared operation Systems allow mang users(from one to servel hundred) to use a computer system inerleavingly at the same time,Other operating systems types inclued real-time systems and multiprocessor systems.为提高系统性能而开发的多道程序设计技术同时也允许分时，分时操作系统允许多个用户（从一个到几百个）同时交错使用一个计算机系统，其他类型的操作系统还有实时系统和多处理器系统。

2.Resource management
资源管理
The management of resources in a computer system is another major concern of the operation system. Obviously. a program cannot use a device of that hardware is unvailable. as we have seen, the operaional sofeware oversees the execution of all programs. It also monitors the devices bening used.To accomplish this. it establishes a table in which programs are matched against the devices they are using or will use. The operating system checked this table to approve or deny use of a specific device
计算机系统中的资源管理是操作系统的另外一个诸方面，显然，如果某一个硬件不能使用，程序不能使用该设备。比如我们看到的，操作系统软件监督者所有的程序的执行。他还监视正在运行的设备。为达到此目的，他建立了一张表，将程序与其正在使用或将要使用的设备相匹配，操作系统通过检查该表允许或拒绝使用某一设备。

3.Control of I/O operations
I/O操作控制
Allocation of a system’s resources is closely tied to the operational software’s control of I/O operations. As access is often neccessary to a particular device before I/O operations may begin, the operating system must coordinate I/O operations and the devices on which thet are performed.In effect.it set up a directory of programs undergoing execution and the devices they must use in completing I/O operations . Using control statements. jobs may call for specific devices.This lets users read data from specific sites or print information at a selected offices.Taking advantage of this facility, data read from one location may be distributed throughout computrized system.
系统组员分配与控制I/O操作的软件密切相关，由于I/o操作开始之前往往需要特定设备进行访问，因此操作系统必须协调I/o操作和所使用设备的关系，实际上操作系统建立了一个执行程序和完成I/o操作所必须使用的设备目录，使用控制语句，作业可以调用指定设备。这使得用户可以在指定站点上读取数据或在选定的办公室内打印信息，利用此点优势，读自某一设备的数据可以分布于整个计算机系统当中。

to facilite execution of I/O operations. most operation systems have a standard set of control instructions to handle the processing of all input and output instructions,These standard instructions,reffered to as the input/output control System(IOCS),are an integral part of most operaring systems.They simplify the means by which all programs being processed may indertake I/O operation.为了便于I/O操作的执行，大多数操作系统都有一套标准的控制指令集处理所有需要输入和输出的指令，这些标准指令称为输出控制系统，是大多数操作系统不可分割的一部分，它们简化了由处理的程序所承担的I/O操作。In effect. the program undergoing execution signals the operating system that an I/O operation is desired. using a specific I/O device,The controlling software calls on the IOCS software to actially complete the I/O operation.Considerin the level of I/O activity in most programs ,The Iocs instructions are extremely vital.实际上，在使用特定I/O 设备时，程序在执行的过程中向操作系统发出所要求的I/O操作指令，控制软件调用IOCS软件去完成实际完成的I/O操作，在大多数程序中考虑到I/o操作的数量很大，因此IOcs指令至关重要。

关于今天：
有很多任务去完成的一天还是比较充实和富有乐趣的，并不是看起来那么无聊。是在是要远离那些负能量比较高的人。生活才能更加有意思。今天完成了一个接口的编写，感觉比较容易，但是自己对编写接口的认识还是比较浅显。有些事情看起来比较浅显，但是动起手来，总是在一些问题上犯错误，归根结底是自己对程序代码不是有很高的理解，虽然是小问题，但是自己心中没有一套相关的心智模型，所以不会去提纲挈领，盲目的去怀疑自己。行动是检验你思想是否正确的唯一标准，这个道理是多么的简单，但是自己总是自作聪明。10分钟写完一份代码，然后用很长的时间去找出问题，自己真的是很无知，很浅薄，而且还比较自鸣得意。