operating system concepts 9th

file here, please take it"->Abstract semantics unrelated to machines The fact is so simple Note: The core of an operating system is to abstract hardware details and serve higher-level software. This is the essence of the system. The so-called process, thread, memory management, system and application software

First, prefaceThe various modules of the operating system have been introduced before, and now we will learn more about process management in the operating system.Ii. Basic concepts of the processIn systems that do not have an OS configured, the program executes sequentially, that is, one program must be executed befor

Linux File System concepts and basic operations (format partitions to create a file system and view a specified file system) 9.1 File System Concept (Overview) The operating system (OS)

PS: The following are the main concepts and calculation formulas for performance testing, which are documented below: A System Swallow metric elements: The Swallow metric (pressure capability) of a system is closely associated with the request for CPU consumption, external interfaces, Io, and so on. The higher the CPU consumption of a single reqeust, the slower t

system Throughput (TPS), user concurrency, performance test concepts and formulasPosted in: DataBase, Linux, UNIX, Windows, Personal diary | Author: a Global person A System Swallow metric elements: The Swallow metric (pressure capability) of a system is closely associated with the request for CPU consumption, exte

threads in the process to continue executing rather than the entire process being blocked, thereby increasing CPU utilization and improving performance from this perspective.3, in the case of multi-CPU or multi-core, the use of threads is not only in the macro-parallel, but also in the micro-parallel.The process has its own independent memory address space, while the thread shares the memory address space of the process.2, the classic threading modelAnother view of process and thread is that th

Real-time Operating system (RTOS) refers to when external events or data generated, can be accepted and fast enough to process, the results of its processing can be within the specified time to control the production process or to respond quickly to the processing system, scheduling all available resources to complete real-time tasks, and control all real-time ta

program needs it.The remainder of this paper is organized in the following form: The 2nd chapter reviews the related work, the 3rd chapter describes the framework of the Contiki system, the 4th chapter describes the design of the Contiki kernel, the 5th chapter describes the concept of Contiki service, 6th, 7 chapters describe Contiki How to handle the library, how to handle communication support , the 8th chapter describes the realization of the pre

most widely used data model.Based on the object data Model (object-based). The object-oriented data model can be seen as an extension of the E-R model with the addition of concepts such as encapsulation, methods (functions), and object identifiers.Semi-structured data Model (semistructured). A semi-structured data model allows data items of the same type to contain data descriptions for different sets of properties. Database IndexThe idea of a data i

Linux disk and file system concepts I. Disk 1. IO Interface Type (1) transmission type classification Parallel Port: The same cable can be connected to multiple devices; IDE has two bus, Master, slave SCSI: Broadband: 16-1; narrowband: 8-1 Serial Port: Only one device can be connected to the same cable; (2) Hard Disk category (theoretical data transmission) IDE (ata): Parallel Port, 133 MB/s SCSI: Parallel

Operating System-process/thread internal communication-semaphore and PV operations, system-pv This article introduces two core concepts of operating system process management: Semaphores PV operation I. Introduction to semaphor

Implement an embedded operating system that can't do anything 1. First determine the CPU. Here we use embedded CPU for simplicity, such as the arm series. The reason why we use a short Instruction Set)The convenience of a type of CPU is that there is no distinction between the real mode and the protection mode, and linear unified addressing is adopted, that is, the segment is not requiredPage-based memory

Implement a simple Embedded Operating System (1) Implement an embedded operating system that can't do anything1. First determine the CPU. Here we use embedded CPU for simplicity, such as the arm series. The reason why we use a short Instruction Set)The convenience of a type of CPU is that there is no disti

Android system development (8)-basic concepts of linx Processes1. in the traditional sense, the proc file system is used to store information on Block devices. The/proc directory is a virtual file system, where the data is stored in the memory, therefore, this directory does not occupy any hard disk space. It mainly in

the operating system? Because it provides the operating system environment through a series of mechanisms. This runtime environment includes: ds/CS/ES/SS, general register group, gdt, LDT, IDT, Ram, Rom, and so on. In fact, from the perspective of the hardware system, there

--- Analysis of osal based on ti cc254xwhen the tool chain configuration is complete, source Insight to show you a source project, without the help of Baidu and development documents, in one or two hours to understand the source of the composition of the framework and interface, for rapid development? In the author's previous blog posts, has been advocating two embedded learning and development concepts: to improve the embedded

destroying threads becomes even smaller. 3. Threads improve performance, although the threads are macro-parallel, but the micro is serial. Threads from the CPU angle do not improve performance, but if some threads involve waiting for resources (such as IO, waiting for input), multithreading allows other threads in the process to continue rather than the entire process being blocked, thereby increasing CPU utilization, which improves performance. 4. In the case of multiple CPUs or multi-core, th

system is a resource manager that runs a large number of applications on the operating system at the same time. All these applications need to operate on different resources, such as I/O, CPU, and Memory. How to allocate resources to these applications, what is the allocation policy, how to ensure the integrity of these resources if resources are operated by dif