scratchpad io

1.1.Event-Driven Event-driven is a programming paradigm, a programming style that specializes in dealing with unknown events by binding an event, activating the thing after an external trigger, and achieving the purpose of performing certain operations. such as the browser's onclick () event1.2.IO Model Basics Before interpreting, there are a few concepts to be explained: User space and kernel space Process switching Blocking of proc

In order to prevent crawlers from crawling articles on unscrupulous websites, we hereby mark and repost the source of the article. Laplacedemon/sjq. Http://www.cnblogs.com/shijiaqi1066/p/3826251.html Socket. Io Socket. Io is used for real-time communication between the browser and node. js. Socket. Io is designed to support any browser and any mobile device. Su

a general concept of performance optimization It is generally believed that Java programs are always slower than C programs, and most people may have heard too much about this kind of advice. In fact, the situation is far more complicated than the old claims. Many Java programs are really slow, but slow speed is not an intrinsic feature of all Java programs. Many Java programs can achieve the efficiency of similar programs in C or C + +, but this is only possible when designers and programmers p

Classes or interfaces related to Java stream operations:Java Flow class diagram structure:concept and function of flowA stream is a set of sequences of bytes that have a starting point and an end point, a generic or abstract of the data transfer. That is, the transmission of data between the two devices is called the flow, the essence of the flow is data transmission, according to the data transmission characteristics of the stream abstracted into various classes, convenient and more intuitive d

Classes or interfaces related to Java stream operations:Java Flow class diagram structure:concept and function of flowA stream is a set of sequences of bytes that have a starting point and an end point, a generic or abstract of the data transfer. That is, the transmission of data between the two devices is called the flow, the essence of the flow is data transmission, according to the data transmission characteristics of the stream abstracted into various classes, convenient and more intuitive d

Classes or interfaces related to Java stream operations:Java Flow class diagram structure:concept and function of flowA stream is a set of sequences of bytes that have a starting point and an end point, a generic or abstract of the data transfer. That is, the transmission of data between the two devices is called the flow, the essence of the flow is data transmission, according to the data transmission characteristics of the stream abstracted into various classes, convenient and more intuitive d

Each peripheral is controlled by reading and writing its registers. Peripheral registers, also known as I/O ports, typically include: control registers, status registers, and data registers.Depending on the CPU architecture, there are two ways that the CPU addresses the IO port:(1) I/O mapping mode (i/o-mapped)Typically, such as the X86 processor regards the peripheral registers as a separate address space (called an I/O address space or I/O port spac

Detail with diagramThe first IO modelBlockingThe second IO modelNon-blocking IOprinciple: change from blocking to non-blocking, come back every once in a while (see once, the kernel will send a system call), if nothing else (for small amount of code), the process actively pollingWhen the server-side socket is setblocking (false), the socket is a non-blocking socket, and when the client link is not received,

From Http://www.cnblogs.com/oubo/archive/2012/01/06/2394638.html, written in great detail.Classes or interfaces related to Java stream operations:Java Flow class diagram structure:concept and function of flowA stream is a set of sequences of bytes that have a starting point and an end point, a generic or abstract of the data transfer. That is, the transmission of data between the two devices is called the flow, the essence of the flow is data transmission, according to the data transmission char

Basic IO Library Type: istream (Input stream) type, provides input operation Ostream (output stream) type, provides output operation Cin, a IStream object, reads data from standard input cout, a Ostream object, writes data to standard output cerr, A Ostream object, usually used for outputting program error messages, to write to standard error GT;GT: Used to read input data from a IStream object File IO clas

encoding in the parameter, which is usually omitted. The system uses the OS lang, and the method byte[] String.getbytes (String charsetname) is the same when the character is converted to a byte stream, which is actually a string to byte[. A buffer in a file operation that refers to a specified amount of memory used to hold data in a file IO data stream, and the purpose of buffering is to increase the efficiency of writing or reading data frequently

Five communication models of the operating system 1. Blocking I/O Is our common socket, the listening port receives the message to process, and returns the result to the client Waits until the I/O operation is complete and does not give control to the program. Socket defaults to blocking mode The application calls an IO function, causing the application to block and waiting for the data to be ready. If the data is not ready, wait .... Data ready, copy

According to UNIX network programming, Io models can be divided into: Blocking Io, non-blocking Io, Io multiplexing, signal-driven Io and asynchronous Io, according to the POSIX standard, there are only two types: Synchronous

8th standard IO library8.1 Object-oriented standard library1. The IO type is defined in three separate header files: iostream defines the type of read-write control window, fstream defines the type to read and write to the named file, and the type defined by Sstream is used to read and write to the string object stored in memory. The types of beauty that are defined in FStream and Sstream are derived from t

1. VmstatCan show the status of the server at a given time interval, including the server CPU utilization, memory usage, virtual memory exchange, IO Read and write conditionsVmstat 2 102: Every 2s10: Statistics 10 times2. ResProcs ——— –memory ———-— Swap–-–io —--system–--cpu-–R b swpd free buff cache si so bi bo in CS us sy ID WA St1 5 0 173436 591640 8272204 0 0 69 55 32 265 6 5 86 3 01 4 0 169912 592224 82

1. Java stream is divided into two kinds(1) Byte stream: can be used to read and write binary files and any type of file(2) Character stream: can be used to read and write text files, cannot manipulate binary filesStream of Byte stream charactersInput InputStream ReaderOutput OutputStream Writer2. Basic usage of File classImport java.io.*;public class io{Files f1 = new file ("E:\\aa.txt");// Create a Document objectSystem.out.println ("File path" +f1

I. BACKGROUND Production environment IBM P560 is currently used for Oracle DataGuard standby machines. When Oracle Apply Archive log, look at the server IO situation, found that Hdisk0, 1 io sometimes reach to 100%. and HDISK2, 3 IO activities are very few. After analysis, Oracle's data file storage directory is located in/oradata, which is based on Hdisk0, 1.

Java.io Package: Provides system input and output via data flow, serialization, and file system Below to understand what is IO stream? The IO stream is used to process data transfer between devices. The Java operation of data is divided into the input stream and the output stream by the way of flow, divided into byte stream and character stream according to Operation data. --------------------------------

In the original: SQL Server A hidden IO performance killer-forwarded recordBrief introductionRecently noticed a high counter in a customer (forwarded records/sec), accompanied by intermittent disk waiting queue fluctuations. This article shares what is the forwarded record and discusses in principle why the forwarded record creates additional IO. Storage principleIn SQL Server, when data is stored as a heap

The provisions in POSIX for synchronous IO and asynchronous IO :Synchronous IO Operation: Causes blocking of process until IO operation completes, asynchronous IO operation: IO operation does not cause process blockingunder UNIX,