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Overview of Signals Signals are one of the oldest methods of process communication used in UNIX. It is a simulation of interruption mechanism at the software level and an asynchronous communication mode. Signals can interact directly between user-space processes and kernel processes. Kernel processes can also use them to notify user-space proc ...

Previous remarks The fs file system is used to read and write system files and directories. This paper will introduce the js file system in detail.   Summary File I/O is provided by standard POSIX functions with simple encapsulation. Use this module through require('fs'). All methods have asynchronous and synchronous forms. The asynchronou ...

Boost library is a portable C++ library that provides source code. As a backup of standard library, it is one of the development engines of C++ standardization process. The Boost library is sponsored by members of the working group of the C++ Standards Committee Library. Some of its contents are expected to become the next generation of C++ St ...

I. Linux The following serial port programming and those components     1. Open the serial port 2. Serial port initialization 3. Read or write serial ports 4. Close the serial port 2. Opening of Serial Port Since the serial port is in the linux It is regarded as a file, so it should be opened before it is operate ...

IO Classification IO Classification: Blocking IO, Non-Blocking IO, IO Multiplexing, Asynchronous IO, etc. Blocking IO 1. Definition: Block if the execution condition is not satisfied when performing an IO operation.Blocking IO is the default form of IO. 2. Efficiency: Blocking IO is a very inefficient type of IO.But because of its simplicit ...

logging module What is logging module Logging module is a module provided by python for logging Why logging is needed We can open the file by ourselves and write in the log, but these operations are repetitive and without any technical content, so python has packaged it for us. With logging, we only need to simply call the interface when record ...

10.6 Monitor io performance iostat command The iostat command is used to monitor the usage of system input and output devices and CPUs.It features a report on disk activity statistics as well as CPU usage.Like vmstat, iostat has a disadvantage that it cannot analyze a process in depth, only the overall situation of the system. iostat -x [ro ...

TCP socket communication How do processes communicate in the network? We know that there are many ways to communicate between local processes, such as pipeline, message queue, shared memory, synchronization and mutual exclusion. These methods require that the two processes of communication are located on the same host. So how to communic ...

SETNX is an instruction in Redis, called "Set If Not Exist", which sets value to key only when it does not exist, otherwise no operation is performed. SETNX can also be used to implement locks in Redis. Problem introduction Before introducing how to use SETNX to implement locks, let's consider the following question: Suppose we now ha ...

It has been a long time since Java8 was released. The new version of java has brought us a lot of exciting new features. The new API s of Date and Time bring new good news to the students who normally need to perform various complex operations on time and date. This article also starts from this point to explore the new features of Data and Tim ...