Мультисерверные ос

Этот подход непосредственно атакует суть проблемы: вся ОС работает как единая гигантская программа двоичной в режиме ядра. Вместо этого, только крошечное микроядро работает в режиме ядра с остальной частью операционной системы работающая как коллекция полностью изолированная в пользовательском режиме сервера и драйверов процессов.

This approach directly attacks the core of the problem: having the entire operating system run as a single gigantic binary program in kernel mode. Instead, only a tiny microkernel runs in kernel mode with the rest of the operating system running as a collection of fully isolated user-mode server and driver processes.

Fig. 4. The Minix 3 architecture.

Как показано на рисунке 4, в Minix 3 микроядро обрабатывает прерывания, обеспечивает основные механизмы управления процессами, осуществляет межпроцессное взаимодействие, и выполняет процесс планирования.

As Figure 4 shows, in Minix 3, the microkernel handles interrupts, provides the basic mechanisms for process management, implements interprocess communication, and performs process scheduling.

Language-based protection

Наиболее радикальный подход приходит из неожиданного источника - Microsoft Research. В сущности, подход Microsoft отбрасывает концепцию операционной системы как единой программы работающей в режиме ядра, плюс некоторый набор пользовательских процессов, запущенных в пользовательском режиме, и заменяет его системой, написанной на новом типе безопасных языков, которые не имеют всех указателей и других проблем, связанных с C и C + +.

The most radical approach comes from an unexpected source – Microsoft Research. In effect, the Microsoft approach discards the concept of an operating system as a single program running in kernel mode plus some collection of user processes running in user mode, and replaces it with a system written in new type-safe languages that do not have all the pointer and other problems associated with C and C++.

Таким образом, каждый из четырех различных попыток улучшить надежность операционной системы направлена ​​на профилактику ошибок драйверов устройств от сбоя системы.

Thus, each of the four different attempts to improve operating system reliability focuses on preventing buggy device drivers from crashing the system.

Пока не известно, какие, если таковые имеются, эти подходы будут широко приняты в долгосрочной перспективе. Тем не менее, интересно отметить, что микроядра - длительное время отвергаемые из-за их низкой производительности по сравнению с монолитными ядрами - может быть делает возвращение из-за их потенциально более высокой надежностью, что многие люди сейчас считают более важным, чем производительность.

It is not yet known which, if any, of these approaches will be widely adopted in the long run. Nevertheless, it is interesting to note that microkernels – long discarded as unacceptable because of their lower performance compared with monolithic kernels – might be making a comeback due to their potentially higher reliability, which many people now regard as more important than performance.

3. POST-READING

3.1. What approach to more reliable and secure OS is more acceptable from your point of view? Why?

3.2. Match the terms in table A with the statements in table B.

Table A

Table B

Operating system Kernel Microkernel Monolithic kernel

The software that manages the sharing of the resources of a computer and provides programmers with an interface used to access those resources. The core of an OS that handles memory allocation, talks to hardware devices, and makes sure everything keeps running. A kernel architecture where the entire kernel is run in kernel space in supervisor mode. microkernel is a minimal computer operating system kernel which, in its purest form, provides no operating-system services at all, only the mechanisms needed to implement such services

4. GRAMMAR IN USE

4.1. Now look through the text again and find all passive forms of verbs (See Grammar Reference 1).

4.2. Complete the gaps in this summary of the text using passive forms of the verbs:

to discuss	to wrap	to intend	to replace	to use (*2)
to make	to develop	to move	to adopt	to know

The problem of operating systems unreliability and insecurity _______ in the text. Current operating systems ______ unreliable and insecure due to two characteristics: they are huge and they have very poor fault isolation. Fortunately, the situation is not hopeless. More reliable operating systems ______ by researchers. There are four different approaches to the problem solving. In the Nooks approach, each driver ______ in a software jacket to carefully control its interactions with the rest of the operating system, but it leaves all the drivers in the kernel. In the paravirtual machine approach the drivers ______ to one or more machines distinct from the main one. Both of these approaches _______ to improve the reliability of existing operating systems. In two other approaches legacy operating systems ______ with more reliable and secure ones. The multiserver approach runs each driver and operating system component in a separate user process. Finally, in the most radical approach, a type-safe language, a single address space, and formal contracts ______ to carefully limit what each module can do. Thus, microkernels _____ in three of the four research projects, but it __ not _____ which of these approaches ____ widely ______.