Linux

The name of the spin lock comes from its characteristics. When trying to lock, if the current lock is already in "Lock "Status, lock the process "Rotate "Test the lock state with an endless loop until the lock is successfully obtained. The spin

There are two machines in the LAN. The two machines can communicate with each other without any firewall. The IP addresses of the two machines are a: 192.168.1.240 B: 192.168.1.102. Suppose A, ssh of machine B allows root logon settings to

LinuxThe difference between memory buffer and cache in the operating system is as follows: Let's start with the free command. Compared with top, the free command provides a more concise view of the system memory usage: $ Free Total used free shared

Create a daemon function: Int daemon_init (void){Int max_fd, RET;Int iret;Struct sigaction Act; Int I;If (iret = fork ()){Printf ("An error occurred while creating the daemon! /N ");_ Exit (4 );}Else if (iret! = 0){_ Exit (0 );}The most critical

1. Introduction The GNU Debugger is called GDB. This program is an interactive tool that works in character mode. In the X Window System, there is a GDB front-end graphics tool called xxgdb. GDB is a powerful debugging program that can complete the

E: unable to obtain the lock/var/lib/dpkg/lock-open (11: The resource is temporarily unavailable) E: The management directory (/var/lib/dpkg/) cannot be locked. Is there any other process occupying it? It is reasonable to say that this problem is

I am going to release mini6410 porting articles in muge0913, including uboot porting (supporting various functions), Linux porting and code analysis, file system creation, driver development and porting, and other details. I hope to help developers

Before downloading Django, make sure that python is installed on your system, input python on the terminal, and check whether python is installed. CTRL + C. Exit. If not, install:sudo apt-get install python 1. Download Django. Go to this page Https:/

1. Install JDK sudo apt-get install openjdk-6-jdk2. Configure Java environment variables Enter the following command: sudo gedit /etc/profile Open the profile and add the following content at the bottom of the file: # set java homeexport

Shared memory is the most useful communication method between processes and the fastest IPC format. This is because all processes share the same memory and there are various Inter-process communication has the highest efficiency. Accessing the

1. The simplest method: Mail-s text ** @ mail.ustc.edu.cn The result of this command is to send an empty email with the title text to the mailbox, but such emails are often treated as spam emails, If you do not receive an email, we recommend that

1) BusIn the system, the bus is described by struct bus_type and defined:Struct bus_type {Char * Name; Name of the Bus TypeStruct subsystem subsys; the subsystem associated with the busStruct kset drivers; a collection of all drivers related to the

Next, let's start with the example and run localhost:/home/XX/examples/ldw.# insmod ldw.ko. Now we can look at/sys/bus/and there is an additional folder named LDD. This indicates that there is a bus type named LDD in the system. At the same time,

1. Interrupt is an electrical signal generated by a hardware device and directly sent to the input pin of the interrupt controller. Then the interrupt controller sends the corresponding signal to the processor. Once the processor detects this signal,

During this time, a capacitive touch screen was created. After experiment, we finally tried it out, because we didn't have this one in the past, and we have accumulated a lot of experience. There are two key points to illustrate: (1) read/write

I. IntroductionGenerally, the link to the function library is completed during the compilation period (compile time. All related object files and libraries are linked to form an executable file ). When the program is running, it has nothing to do

Implementation platform: redhat9.0 Author: Lu Yan Physical requirements: two common PCs with serial ports System Requirements: Linux Principles: one of the two Linux PCs serves as the server, listening to COM1, that is,/dev/ttys0, And the other

In the Linux kernel, it is easy to confuse when to use spin_lock_irqsave and spin_lock_irqsave. First, let's take a look at how the code is implemented. Call relationship of spin_lock Spin_lock | + -----> Raw_spin_lock | + ------> _ Raw_spin_lock | +

The Select system call enables our program to monitor the State Changes of multiple file handles (file descriptor. The program stops at select and waits until one or more of the monitored file handles change their status. There are a lot of files in

Dynamic Audio Power Management for portable devices ========================================================== ============== 1. Description ==================== Dynamic Audio Power Management (dapm) is designed to allow portable Linux devices to