写译 — 系统调用机制在内核态和用户态切换中发挥的作用？
- Author : Cyan_RA9
- 和大家分享英语写译，包括计算机英文教材，计算机基础，中英文诗词，英文名著，日常对话等，每一篇文章 我都会分别给出“原文内容”，“第一版翻译” 和 “第二版翻译”，以及“生词整理”共四部分。
- 写译 — 系统调用机制在内核态和用户态切换中的作用？
【原文内容】
- 通常，内核态不直接运行用户程序（即便内核态可以访问用户空间），而是通过系统调用机制安全地与用户空间交互。具体来说，当用户程序需要执行某些特权操作时，它会通过 系统调用（System Call） 请求操作系统的服务。系统调用会触发从用户态到内核态的切换，此时CPU会执行操作系统提供的服务代码来完成用户请求的操作，执行完成后再转换为用户态继续执行用户程序。这种设计确保了系统的安全性与稳定性，同时实现了用户程序与内核的隔离。
【第一版翻译：（润色前，手译）】
- Usually, the CPU don't execute user program directly when it's in Kernel Mode(even it has the capacity to access user space at this moment), rather than interacting with user space in security through System Call mechanism. More specifically, the CPU will request for services of Operating System through System Call when the user program need to execute some of the privileged operations. System Call will trigger the switching from User Mode to Kernel Mode, hence the CPU will execute the serving code provided by the Operating System to fulfill what the user requested for and then switch to the User Mode to continue to execute user programs after the execution of the serving code. This kind of design ensures security and stability of system, simultaneously achieving the isolation between user programs and kernel.
【第二版翻译：（润色后，雅思水准）】
- Typically, the CPU doesn't execute user programs directly when it is in Kernel Mode(even though it has the capacity to access user space at this moment); Instead, it interacts securely with user space through System Call mechanism. More specifically, when a user program needs to execute some of the privileged operations, it requests services from the Operating System through a System Call, This System Call triggers the transition from User Mode to Kernel Mode, hence the CPU executes the service code provided by the Operating System to fulfill what the user requested and then switches back to the User Mode to continue to execute the user programs after completing the service. This kind of design ensures the security and stability of the system, simultaneously achieving the isolation between user programs and the kernel.
【生词整理】
- typically：adv.通常，往往，典型地，有代表性地（typically 相比 usually更适用于技术或学术语境）
- System Call：phrase.系统调用
- System Call mechanism：phrase.系统调用机制
- More specifically：phrase.具体来说，具体地（当上文中已经提出了一个宽泛的概念，想要进一步缩小范围，提供更详细的信息时，可以用这个短语）
- request：v&n.请求，要求（request作动词时，后面直接跟宾语，不需要“for”，作名词时则常与for搭配）
- User Mode：phrase.用户态，用户模式
- Kernel Mode：phrase.内核态，内核模式
- service code：phrase.服务代码
【写译手稿】
