Earlier this year, I joined a new majority in the study of social sciences and political groups, and then I have to explain to them I am currently doing. There are about 10 people in this group, there are one or Nike Free Run Womens two people is the core concept of a preliminary understanding (actually because they are engineering students), but others in the group but then the kernel ignorant - they are waiting for me to They explain explain. Well, for those little Nike Free TR Fit engineering students the basic concepts, the preferred method is to play an analogy about cars (at least get a male audience). However, in practice what you can on the car compared to the kernel to do? You can not be compared directly to the core engine or chassis, and even the vehicle's path. When you try to explain what a kernel programmer to take advantage of the operating system doing even worse. When the car body as a metaphor for the kernel in the end what is it? A kernel programmer and can not be directly defined as a mechanic. So, the definition of the class of car designers do? After a long period of intermittent explanations and hesitation, I tried 先向 group of girls explain, it's like the kernel developers for automotive design laws of physics run. Unfortunately, they Mens Nike Free 3.0 Wool Skin Shoes Blue Yellow still do not believe it. Do you have a better explanation? 'The Matrix,' released in 1999, so I soon became interested in the operating system, and finally I was FreeBSD (a free Unix systems) project to become a kernel developer. But at the same time, I have been fascinated by learning and The Matrix, he spent a lot of time. Sometime in the early twenty-first century, probably in 03 or 2004, I wrote an article, I will, 'Matrix' characters and what they happen and its sequel with a (virtual) operating system analogy of a system. In order to save the old article down, prevent the loss of contents in the forgotten server, it will be moved to the cloud, I copy and paste in the following initial content of the article. Tip: You can extended the metaphor further. ----------------------------------------- Since the operating system design, implementation and maintenance It is one of my greatest interest, and the first time I watched the 'Matrix', so they are some of the concepts of the movie were thinking, and think to some extent they exist similarities with the operating system: The Matrix World: the equivalent of an operating system (ordinary world in which we human beings live, the kernel ('Matrix' itself)) has a user space are running. Obviously, this is a rather defective operating system. ʱ?? ʱ?? People: the equivalent of the process, including the kernel and user processes. General process, 'non-privileged' process and background process with root privileges ('agents') have a lot of difference. Daemon with root privileges can use privileged ports, destroy random process, memory management and so on. Matrix: the equivalent of the kernel. It appears to be based on the Nike Free TR Fit core structure of messaging, rather than micro-kernel structure (some parts even though they have micro-kernel, such as having a large number of kernel processes, among processes are strictly independent, and messages have Nike Free Womens been mentioned in passing mechanism). The kernel manages all processes, as well as on Air Jordan Outlet the progress of the operation (such as maintaining an active process, the process of service recovery process). But this is still an obvious 2015 Nike Mens Nike Free 3.0 Wool Skin Shoes Blue Yellow Free 5.0 security flaw: Some user processes can transfer part of their code into the kernel space and execute (because of a bug). Only certain system calls affected (like 'phones'), which expands the privileges of the user process tamper return stack, so if the process receives a signal, it will produce mistakes and garbage collection ( If you are killed in the Matrix, then you really dead). Oracle: the equivalent process (task) scheduler. It has all the data processing monitor (resource utilization), and in advance (which obviously) know how their optimal scheduling. Agents: equivalent systems monitoring / intrusion prevention / protection system has heuristic operation (IDS (Intrusion Detection System) / IPS (information processing system)). Most of them have a core part (or kernel module) but basically it is Nike Air Max those background processes with superuser privileges to run in user space. Their duty is to find the process of trying to break into the system and destroys security. The trainman: the equivalent of the kernel and user space gateway / messaging queue. If you want lawfully in user space and kernel data transfer must be done through here. Of course, you may never trapped in the queue queue. The Merovingian: the equivalent of network / IPC (interprocess communications) stack. Its duty is to master the process between what Mens Nike Free 3.0 V2 Shoes White Black Red happened. An accidental error input / output data will be manifested in the form of a bug. Vampires / ghosts: the equivalent of the old version of the API / KPI compatible device. Due to historical reasons, these codes are not perfect, but the code and some kernel process is not complete but Air Max 2011 Womens Grey Green Black should not be connected. The Architect: equivalent kernel monitoring (managers) hardware, responsible for monitoring the process, destroy those processes 'abnormal' and the destruction of the restart process. Because it is a real-time system with high reliability, hardware debug and monitor clearly has the highest priority, but also absolutely reliable (and therefore, in order to reduce the possibility of error, but also reduce its complexity) ʱ?? Because it frequently availability check, resulting in excessive misconfigured, consume too many Air Max 2011 Men Blue Black resources, thus affecting the normal functioning of the operating system. Keymaster: equivalent security / privilege subsystem. It is very stable, but unfortunately relies on Nike Air Max 95 Men imperfect VM (virtual memory) system and the IPC system, so it can be utilized to process more privileges. The Plot: In the case of system is highly loaded (lots of process, frequent memory access), there is a design flaw between the VM (virtual memory) system, process management system and scheduler. This is a composite error, resulting in at least three problems: 1, the memory page is damaged or memory pages allocated to those processes that do not belong to them. Since the kernel and user-space shared virtual memory, in order to prevent exposure of sensitive data, improve security, the process can be either because the other party's memory pages are destroyed. 2, interprocess communication, which is very bad, even damaged or memory data structure than the process of loading too often caused by a deadlock, but had to wait for the buffer worse. 3, system monitoring becomes unstable, cyclic destruction and restart the process, unaware of this operation will increase the burden of additional memory and processes and worse, and finally greatly increased inter-process virtual memory page disrupted speed ʱ?? Agent Smith: the equivalent of a privileged IPC daemon, with parts of the kernel module functions. It is closely related with the kernel module, and can not pass the integrity check and a shared data structure with the kernel. Once it is destroyed off another privileged process, it can also hide in the middle of a system call in order to monitor persons restart it, this time it's the process descriptor have been destroyed, which makes most of its program code to be executed in the kernel ʱ?? It will continue to work long hours in this damaged state, carve into a loop, and the process incorrectly marked as security vulnerabilities, to rewrite some of its pages. Neo: originally a web server process user space, virtual memory, it is given the damage caused by super-user privileges as well as having a high priority CPU. Finally it got executable memory pages with IDS process Simth mixed, but not data page. Soon it began the destruction process, including Smith and its own damaged parts. The Ending: Last Smith tried to kill the process scheduler process, but this is because he is scheduled by the dispatcher, he does not do that. The system becomes abnormal is because the scheduler can not perform the task, including interrupt service, but in the dispatcher's virtual memory mirroring (again, the mirror also happens with Neo processes partially shared) in the part of the code, but Smith can still perform. Since only two processes can run, they want to kill each other. At the same time, because there is no interruption services, hardware watchdog timer do not wake up, it inserts an Air Max 2011 Womens Blue Black NMI (non-maskable interrupt), so that they wake up the monitoring system. This makes the system is in a critical state and begins Nike Air Max 95 Men to kill all processes, then restart the process of being killed to make the system starts up again. end! Post hoc analysis: the operating system when there is an inherent design flaw, especially among virtual memory, interprocess communication, and monitoring subsystem in these areas, which will lead to global memory between processes is destroyed and in the process address space to produce a small amount fatal flaw. Recommendation: To ensure proper process priority, more needs to be fine-tuned to reduce the priority inversion and imbalances. It is possible to rewrite the virtual memory system, the development of versions consume fewer resources to replace the IDS system. If the system load is above a certain threshold, the system monitors must be amended, but will not start a lot of action. Well, this is an article about The Matrix does not involve any form of 'free will' exposition.how to explain the operating system kernel to a layperson?