emarketing concepts

1. Linux boot up2. linux File Management3. Architecture of Linux4. Linux command line and command5. linux file Management related commands6. Linux text stream7. Linux Process Basics8. Linux Signal Basics9. Linux Process RelationshipsTen. Linux UsersLinux from program to processLinux multi-Threading and synchronizationInter-process communication between LinuxImplementation of Linux file systemLinux Common commands====================================================================================

(Transition Engine): is to execute the strategy made by PE and only run PE and TE on DC.6.STONITHD componentsSTONITH (Shoot the other node in the head, "headshot"), this way directly to operate the power switch, when a node fails, the other node if it can detect, will be issued through the Network command, control the fault node power switch, through the temporary power, And power-up means that the failed node is restarted, which requires hardware support.Stonith Application Case (master-slave

is encrypted.(Reduce the number of different users to set the same password, resulting in the same ciphertext security risks)When the user logs in, the random code is encrypted with the password, and then the ciphertext is matched and the user is entered.Add users, Groups:Useradd USERNAMEGroupadd GRPNAMEExample:Useradd tom--Adding usersTail-1/etc/passwd--View the last row of recordsTAIL-1/etc/shadow--Viewing user informationpasswd tom--to set a password for the userRedhatRedhatTail-1/etc/shadow

deployed with EJB technology can be limited to specific platforms. EJB (Enterprise JavaBean) is part of the Java EE, which defines a standard for developing component-based enterprise multi-application applications. Features include network service support and core development tools (SDKs). In Java EE, Enterprise Java Beans (EJB) is called Java Business Bean, which is the core code of the kernel, namely the session bean, the entity bean Bean) and the message-driven bean (Messagedriven bean).3.J

meta programmingRefers to the preparation of meta-programs1.4Meta-languageLanguage for writing meta-programs1.5Target languageWriting the language of the target program1.6SummarizeWe write programs in the C + + language, the C + + language is a target language, after processing by the compiler, generates an. obj file, inside the. obj file is the target program, after the linker link, forms an executable program. From the DSL point of view, meta-programming is written in a DSL language to run, a

mapping and also inherits the address returned by Mmap (), so that the parent-child process can communicate through the mapped area. Note that this is not a general inheritance relationship. In general, child processes maintain separate variables inherited from the parent process. The address returned by the mmap () is maintained by the parent-child process together.The best way to implement shared memory for a genetically-related process should be to use anonymous memory mapping. At this point

"True+ """True"The difference between the 12:ecmascript operators is that they can be applied to many values, such as: strings, numeric values, Booleans, and even objectsvar x= ""; x + +0var x=true;x++1True+false1True+ """True"True+ "CCC""TRUECCC"true+{}"True[object Object]"{}++Vm2136:3 uncaught syntaxerror:unexpected Token}var x={};x++NaN({}) +true"[Object Object]true]13: Bitwise operator (unsigned right shift >>>, signed right shift >>, left shift var x=100;X=~x-101var x=253Undefinedvar x=25

, assuming that the function Arraywrite_b executes, and thread B is switched out by the operating system scheduler. Then the array member is assigned the value of Case 3 as shown. At this point, thread A is re-dispatched, and when thread a finishes executing the function arraywrite_a, the array member is assigned a value of 4. At this point, we see that the member assignments in the global arrays array are not expected by thread A, nor are they expected by thread B. Such a process is called race

Statistics commands sort, WC, uniq Sortsort [-fbmnrtuk] [file or stdin]-F ignores case-B ignores the front space-m sort by month name-N using pure numeric sorting-R Reverse Sort-U The same data item appears only one item-T delimiter-K to sort by that intervalegcat/etc/passwd | Sort-t ': '-K 1//pair to: Sort the first column of the split WC statistic Word, line or character numberWC [-LWM]-L Number of rows-W Words-M character CountegCat/etc/profile | Wc-lwm Uniq duplicate data a

chapters.8. NotesThe standard C language comment is a string that begins with "/*" and ends with "*/". The comment is between "/*" and "/*". When the program compiles, no comments are processed. Comments can appear anywhere in the program. Comments are used to prompt or explain the meaning of the program to the user. Statements that are not used in the debugger can also be enclosed in annotations so that the translation is skipped and the comment is removed after the debug is finished.In additi

, so that the Run method we wrote was executed.Descriptionpublic void Run () {If (target!=null) {Target.run ()}}When the thread object is generated using the inherited thread, target is empty and nothing is executed when the second method is used to execute the Target.run (), the target is the instance object of Runnable, which is the method to execute the overrideSummary: The difference between two types of generated thread objects:1. Two methods are required to execute the thread's Start metho

processesExport Varname=valueExportThe script starts a child shell process when it executesScripts that are started on the command line inherit the current shell environment variable:Scripts that are automatically executed by the system (not command-line startup) require a self-defined environment variable:Positional variables:$1,$2,.....Special variables:$?: previous command execution status return value:After the program executes, there may be two types of return valuesProgram execution Resul

and instructions (including external instructions), with the functions of regular notation, command and flow redirection, to achieve the purpose we want for the purposes we desire. Shell script is like a batch (. bat) of the early DOS era, the simplest feature is to write many instructions together, so that users can easily be able to use one touch method to deal with complex motion (execute a file "shell script" to perform multiple instructions at once)。 Shell script also provides important

returns to the user state from interrupts, exceptions, and system callsRegardless of whether it is returned from an interrupt, an exception, or a system call, the Ret_from_sys_call () is called, and the dispatch flag is detected by this function, and the scheduler is invoked if necessary. So why call the scheduler when it returns from the system call? This is of course from efficiency considerations. Returning from a system call means leaving the kernel state and returning to the user state, wh

the number of arguments passed to the function, the named argument without passing the value is automatically assigned the undefined value (all parameters in the ECMAScript pass the value, it is not possible to pass the argument by reference)24ECMAScript function is not overloaded25 Unlike other languages, ECMAScript does not define separate data types for integer and floating-point values, and Numer types can be used to represent all valuesThere is no need to specify the return value of a func

corresponding to a property in Bo, for synchronization and security considerations, it is best to give DAO or service calls, rather than using Packcode,backingbean, or Bo tune.DAO, the data access layer, the object in the Vo,backingbean can be put into ....DTOs, seldom used, are basically put into DAO, but play a role in transition.QO, is to put some with persistent query operations with the statement into the.The basic elements and methods used in the VO,V layer are placed therein. If you want

1. Conceptual understanding In the case of network programming, we often see synchronous (Sync)/asynchronous (Async), blocking (block)/non-blocking (Unblock) Four ways to invoke: Sync: synchronization is when a function call is issued, and the call does not return until the result is obtained. It is necessary to do one thing, and so on before the next thing is done. For example, common B/S mode (sync): Submit request-> wait

the variable.replicas are independent of each other so that each thread is free to modify its own copy of the variable without affecting other threads. Common methods of ThreadLocal classThreadLocal (): Create a thread-local variableget (): Returns the value in the current thread copy of this thread's local variableinitialvalue (): Returns the "initial value" of the current thread for this thread's local variablesSet (T value): Sets the value in the current thread copy of this thread's local va

single machine (simulate the cluster)Vim start_rabbitmq_cluster.sh#!/bin/bashif [[$#! = 1]]Thenecho "Usage: $ process_num"Exit 1FiHost_name= ' hostname 'Start_num=0Process_num=$1end_num=$ ((start_num + process_num-1))rabbitmq_node_port=5672 rabbitmq_nodename= "Rabbit" rabbitmq_server_start_args= "-rabbitmq_management listener [{ port,15672}] "rabbitmq-server-detachedFor ((i=$ (start_num+1); iDorabbitmq_prot=$ ((i + 5672))manage_port=$ ((i + 15672))Node_name= "Rabbit_$i"Echo $RABBITMQ _protEcho

Asp.net| Server | concepts | Controls the advent of Microsoft asp.net atlas almost subverts the entire traditional ASP.net development concept, in theory, the most "pure" Atlas application will move all the presentation layers to the client, The server side is just the service that the client needs to provide. So far this client-side programming model has not been very powerful IDE support (think about writing, debugging JavaScript is painful ...) , t