硬件保护和软件保护_什么是硬件保护？

硬件保护和软件保护

A computer contains various hardware like processor, RAM, monitor etc. So OS must ensure that these devices remain intact ( not directly accessible by the user).

计算机包含各种硬件，例如处理器，RAM，监视器等。因此，操作系统必须确保这些设备保持完整(用户不能直接访问)。

It is divided into three categories:

它分为三类：

1)CPU保护 (1) CPU Protection)

It means that a process should not hogg (hold) CPU forever otherwise other processes will not get the process. For that purpose, a timer is introduced to prevent such a situation. A process is given a certain time for execution after which a signal is sent to the process which makes the process to leave CPU. Hence process will not hogg the CPU.

这意味着一个进程不应永远占用(保持)CPU，否则其他进程将无法获得该进程。为此，引入了计时器以防止这种情况。给某个进程一定的执行时间，之后将信号发送到该进程，使该进程离开CPU。因此，进程不会占用CPU。

2)记忆保护 (2) Memory Protection)

There may be multiple processes in the memory so it is possible that one process may try to access other process memory.

内存中可能有多个进程，因此一个进程可能会尝试访问其他进程内存。

To prevent such situation we use two register:

为了防止这种情况，我们使用两个寄存器：

Base Register

基本寄存器
Limit Register

限价登记

Base register store the starting address of the program and Limit Register store the size of the process. So whenever a process wants to access address in memory then it is checked that it can access the memory or not.

基址寄存器存储程序的起始地址，而极限寄存器存储过程的大小。因此，只要进程想要访问内存中的地址，就会检查该进程是否可以访问内存。

3)I / O保护 (3) I/O protection)

To ensure CPU protection OS ensure that below case should not occur

为了确保CPU保护OS，请确保不会发生以下情况

View I/O of other process

查看其他进程的I / O
Terminate I/O of another process

终止另一个进程的I / O
Give priority to a particular process I/O

优先处理特定的流程I / O

If an application process wants to access any I/O device then it will be done through system call so that OS will monitor the task.

如果应用程序进程要访问任何I / O设备，则将通过系统调用来完成，以便OS监视任务。

Like In C language write() and read() is a system call to read and write on file. There are two modes in instruction execute:

像在C语言中一样， write()和read()是对文件进行读写的系统调用。指令执行有两种模式：

User mode

用户模式

The system performs a task on behalf of user application this instruction. In this mode, the user cannot directly access hardware and reference memory.

系统代表用户应用程序执行此指令的任务。在这种模式下，用户无法直接访问硬件和参考存储器。
Kernel mode

内核模式

Whenever a direct access to hardware is required a system call is used by the application program.

每当需要直接访问硬件时，应用程序就会使用系统调用。

翻译自: https://www.includehelp.com/operating-systems/hardware-protection.aspx

硬件保护和软件保护