balloons io

One, I/O ports Port is the address of a register that can be accessed directly by the CPU in an interface circuit. Almost every peripheral is done by reading and writing registers on the device. The CPU sends commands to the registers in the interface circuit through these address ports, reading status and transmitting data. Peripheral registers, also known as "I/O ports", typically include three categories of control registers, state registers, and data registers, and the registers of a periph

Then draw on the theory in the UNIX Network programming Volume:The 2 main objects involved in IO operations are program processes, system cores. As an example of a read operation, when an IO read occurs, it typically goes through two steps:1, waiting for data preparation2. Copy data from the system kernel to the operation processFor example, in a read operation on the socket, step 1 waits for the network pa

Article Title: IO system performance: monitors IO performance in Linux. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source. Dd command Dd actually works on a relatively low-Layer * nix platform tool for data copying and conversion, but because dd commands support some specia

Today, when using AB for stress testing, it is unintentional to discover:Requests per second:xxx [#/sec] (mean)Ab-n 5000-c http://www:8080/upload/5kb.jpg (nioserver:700 aio:400)Ab-n 5000-c http://www:8080/upload/18kb.jpg (nioserver:560 aio:360)Ab-n 2000-c http://www:8080/upload/134kb.jpg (nioserver:330 aio:300)Ab-n 2000-c http://www:8080/upload/134kb.jpg (nioserver:330 aio:260)ab-n 3000-c http://www:8080/upload/134kb.jpg (nioserver:300 aio:310)Ab-n 5000-c http://www:8080/upload/134kb.jpg (nioser

Java-IO streams, Java IO stream characters Java text (char) is a 16-bit unsigned integer and unicode (dubyte encoding) of characters ). The file is a data sequence of byte. A text file is a storage result of serialized text (char) sequences into bytes according to a certain encoding scheme (uft-8, utf-16be, gbk. Pipeline stream (Reader, Writer) --> operates on text and text files 1. Processing of charact

Java learning notes-10. io stream, java learning notes-10.io 1. The input stream can only read data from it, but cannot write data to it. The output stream can only read bytes of data. 2. The InputStream types include: ByteArrayInputStream contains a memory buffer, which is extracted from byte. FileInputStream obtains bytes from the file. ObjectInputStream is used to restore serialized objects. PipedInput

IO Stream Application-small resource manager, io stream Resource Manager Small Resource Manager 　　　　 　　　　　　　 Private void LoadTreeView (){DirectoryInfo dir = new DirectoryInfo (@ "E :\");DirectoryInfo [] dirs = dir. GetDirectories ();Foreach (DirectoryInfo item in dirs){TreeNode tn = new TreeNode ();Tn. Text = item. Name;Tn. Tag = item. FullName;This. treeView1.Nodes. Add (tn );} }Private void Form1_Load

, Len); the } - Wuyi bos.close (); the bis.close (); - } Wu - // byte buffer stream reads and writes one byte at a time About Private Static voidMethod3 (file srcfile, file destfile)throwsIOException { $Bufferedinputstream bis =NewBufferedinputstream (NewFileInputStream ( - srcfile)); -Bufferedoutputstream BOS =NewBufferedoutputstream ( - NewFileOutputStream (DestFile)); A + intby = 0; the while(by = Bis.read ())! =-1) { - Bos.write (by); $

[] args)throwsIOException { - //Encapsulating Data Sources -BufferedReader br =NewBufferedReader (NewFileReader ("B.txt")); - // Encapsulate Destination (Create collection Object) -arraylistNewArraylist(); - in //read data stored in the collection -String line =NULL; to while(line = Br.readline ())! =NULL) { + Array.add (line); - } the * //Freeing Resources $ br.close ();Panax Notoginseng - //iterating through the collection the

Mylinenumberreadertest, as follows:1 Packagecn.itcast_09;2 3 ImportJava.io.FileReader;4 Importjava.io.IOException;5 6 Public classMylinenumberreadertest {7 Public Static voidMain (string[] args)throwsIOException {8 //Mylinenumberreader MLNR = new Mylinenumberreader (New FileReader (9 //"My.txt"));Ten OneMyLineNumberReader2 MLNR =NewMyLineNumberReader2 (NewFileReader ( A"My.txt")); - - //Mlnr.setlinenumber (ten); the - //System.out.println (Mlnr.getlinen

Synchronous and asynchronous Io, blocking and non-blocking Io Many times we often see synchronous and asynchronous, blocking, and non-blocking. In some cases, the synchronization and blocking operations are placed with equal signs. Asynchronous and non-blocking draw an equal sign. In fact, this is not correct. Synchronization is not equal to blocking, while Asynchronization is not equal to non-blocking. Nex

Sys_select ()------> Do_select ()The final call to the file descriptor fd corresponds to the struct file type variable of the struct file_operations *f_op of the poll function.The function that poll points to returns information that is currently read and written.1) returns read and write information if it is currently readable or writable.2) If it is not currently read/write, block the process and wait for the driver to wake up, call the poll function again, or return the timeout.3, the driver

[] args)throwsunsupportedencodingexception {Try { //1. Declaring an input streamFileInputStream fis=NewFileInputStream ("D:/test/s1.txt"); //2. redirectionsystem.setin (FIS); //3. Read the contents of the system.in standard input streamBufferedReader br=NewBufferedReader (NewInputStreamReader (system.in, "gb2312"));//Set character encoding//4. Output the contents of the system.inString line=NULL; while((Line=br.readline ())! =NULL) {System.out.println (line); } //5. Close

layout algorithm used by most file systems, the files in each directory tend to be distributed adjacent to the disk.2,inode number: Using inode sorting is more efficient than path sorting, and in general, the order of the inode means the order of the physical blocks.3, the physical block of the file: the physical block is obtained through the file logical block, and then sorted again. The first step is to determine the number of blocks in the file. This can be done through the stat () call. Sec

, directly submit the command + user buffer to the kernel driver, and then return immediately. At this time, the user thread can continue to run and do other things. When you want to know the command completion status, you can use getqueuedcompletionstatus to obtain the completed request and data. Therefore, you can submit a large number of IO requests first, and then process and return them slowly. The reason why iocp is more efficient than epoll is

Basic Application of socket. io tutorial (2) socket. io tutorial Preface Socket. IO supports timely, bidirectional, and event-based communication. It can work on every platform, every browser, and every device, with the same reliability and speed. Real-time analysis: pushes data to clients, which are expressed as real-time counters, charts, or log customers.

Custom IO Async Basics:--all requests are based on the socket implementation, and a request is a socketSocket.setblocking (False) does not need to block, a request is over send another, will error, need to solve--io multiplexing [is a synchronous request]IO multiplexing has epoll, poll, select, knowing that epoll performance is better than others [Epoll find the

Objective: In general operations work often encounter such a scenario, the server's IO load is very high (util in iostat), but unable to quickly locate the IO load source process and source files resulting in the inability to make the appropriate policy to solve the problem. This phenomenon is more common on MySQL, and before 5.6 (Performance_schema provides IO