virtualbox pros and cons

server, maintain a set of basic data, the client does not need to install, through the browser can be used;L Okit allows leaders to get the information they want when they need to focus on a project, and no longer requires project managers to spend a lot of time organizing reports and sending emails.L Okit can be deployed to the Internet so that project teams can be distributed anywhere and can work together as long as they can connect to the network.1 servers, 5 minutes, set up a management en

, Git is suitable for simple software projects, typically some open source projects, such as the Linux kernel, busybox, etc.Instead, SVN excels at multi-project management.For example, you can store a bsp/design document/File system/application/Automation compilation script for a mobile project in an SVN repository, or a file system that stores 5 mobile projects in one SVN.The n (number of items) * m (Number of components) warehouse must be established in Git. Only a maximum of n or M will be re

of network services, then the single-point nginx can not be satisfied, when the use of LVS or commercial array is the first choice, nginx at this time as a LVS or array of nodes to use, The specific LVS or array is selected according to the size of the company and the budget to choose, the application delivery function of the array is very powerful, I used in a project, cost-effective is much higher than F5, commercial first choice! But in general this phase of the relevant talent to keep up wi

1. The advantages and disadvantages of Visual Source safe:Advantages: If the development tool is vs.net, with VSS more suitable, convenient, installation configuration and use are simple, version control is simple, after playing the label, to restore to this version is simplerDisadvantage: The base LAN, low efficiency, VSS itself is poor security, only support widows platform2. Concurrent Version System Advantages and disadvantages:Advantages: Once become the mainstream, do not worry about data

core function is very few, does not install the plug-in basically cannot use.BUGZILLA :Advantages:1, Bugzilla no charge,2, Bugzilla now has Chinese version supportDisadvantages:1, Bugzilla can only manage defectsApple XCode :Advantages:1, you can automatically create a classification chart.2. Automatically provides undo, redo, and save functions without writing any coding.Disadvantages:1, after the update version, a plugin may become invalid.What are the current popular source program version m

expansion of network services, then the single-point nginx can not be satisfied, when the use of LVS or commercial array is the first choice, nginx at this time as a LVS or array of nodes to use, The specific LVS or array is selected according to the size of the company and the budget to choose,the application delivery function of the array is very powerful, I used in a project, cost-effective is much higher than F5, commercial first choice! but in general this phase of the relevant talent to k

choice, at this time these things get started fast, easy to configure, on the seven layer above the use of HTTP protocol can. This is the first choice.The second stage: with the further expansion of network services, then the single-point nginx can not be satisfied, when the use of LVS or commercial array is the first choice, nginx at this time as a LVS or array of nodes to use, The specific LVS or array is selected according to the size of the company and the budget to choose,the application d

file access A) consumes Namenode of memory b) Seek time exceeds read time 3. Concurrent write, File random modification A) A file can only have one writer b) only support append HDFs processing of a large number of small files: compression of small files, that is, 10,000 small files in HDFs only as a file for storage, compression processing.

Singlemode Fiber: Single mode optical fiber can only transmit in a given working wavelength.Advantages: The transmission bandwidth of single mode fiber is wide and the transmission capacity is large. Optical signal can be transmitted along the axial direction of light, so the loss of light signal is very small, discrete is also very small, single-mode fiber backbone cabling The maximum distance of 3000m.Cons: High prices.Multimode fiber: multimode fiber optical signal more than one wavelength (m

It is not the IT entrepreneurial advantage of it people:1) More respect for market-oriented rather than technical2) More attention to product details rather than technology3) more focused on enterprise balance rather than technologyIt is not the IT entrepreneurial disadvantage of it people:1) Abandonment of technical planning due to marketing2) Loss of technical agility due to demand3) The technology gene is erased because of balance It is not the IT business of it entrepreneurial

Comparative analysis of the pros and cons of mainstream PHP frameworks, comparative analysis of framework advantages and disadvantages PHP is a popular open source server-side scripting development language both at home and abroad. Able to adapt to the development needs of large and medium-sized projects. In this article we will introduce several mainstream PHP framework and its related advantages and disa

width and spacing.. ALLEGRO has a stroke function, with skill added functionality.. Allegro is more convenient for multi-person collaboration.What are the hazards of the main components of the substrate (FR4) and PP plates and the Chinglei rays?Commonly used FR-4 and P.P. Board, the main ingredient is epoxy resin and glass fiber . The harm you refer to, should only be the Chinglei after the shooting process will produce harmful substances. In the laser processing after the main material is carb

of the Web.5.AJAX points of attention and applicable and non-applicable scenarios(1). Attention PointWhen Ajax is developed, network latency-that is, the interval between a user sending a request to a server to make a response-requires careful consideration. Not giving users a clear response, without proper pre-reading data, or improper handling of XMLHttpRequest, will make users feel delayed, which users do not want to see, but they do not understand. A common solution is to use a visual compo

the previous service-side code is now placed on the client), destroying the original standards of the Web. Ajax attention points and applicable and non-applicable scenarios(1). Attention Pointwhen Ajax is developed, network latency-that is, the interval between a user sending a request to a server to make a response-requires careful consideration. Not giving users a clear response, without proper pre-reading data, or improper handling of XMLHttpRequest, will make users feel delayed, which users

controlsMain advantages: Multi-level linkageCons: Display a field as much as possibleDropDownList control is generally used for multi-level linkage, such as the linkage of provinces and cities, the main point here is to set the field for DropDownList to display fields and values to display the field is:After binding, the results are as follows:To this point, we have analyzed the merits and demerits of the data-bound control of ASP. We only have a deep understanding of the characteristics of eac

, it is easy to appear background break2 The time cost of flattening pictures is increased, CSS sprites need to measure the exact position of each background unit by Photoshop or other tools when developing.3 Coding and maintenance time cost will increase, CSS sprites in maintenance, if the page background has a little change, generally will change this merged picture, if in the original place, and can only (best) add pictures, so that the image of the byte increases, but also to change the CSS.

ultra-fast interpreter written in C + +, which has another unique feature: You can download the engine and embed it in any application. The V8 JavaScript engine is not limited to running in a single browser. As a result, node. JS actually uses the V8 JavaScript engine written by Google and rebuilds it to be available on the server.node. JS Benefits:1, the use of event-driven, asynchronous programming for network services and design. In fact, the anonymous function and the closure feature of Jav

shared, which does not affect the program's operation, but it gives us code and trouble reading the program. In addition,spring3 MVC validation is also a bright spot, support JSR303, processing AJAX Requests is more convenient, just a note @responsebody, and then directly return the response text. Send the following code:[Java]View PlainCopy @RequestMapping (value= "/whitelists") Public String index (Modelmap map) { Account account = Accountmanager.getbydigitid (Securityconte

, theaccept method is synchronous, only when the user's request to come, will continue to execute down, Or else you'll be stuck here. Preferably with multi-threaded use, the front of the VC under the Chat tool when the communication part of a separate open a thread, the main thread continues to run to the layout interface. When there is data arriving, the message can be sent. AsynchronousAdvantage: thread does not snap to deathCons: trouble to take the proxy method so we generally use asynchrono

developers do not need to consider the logical structure of data, only the business data entities. Hibernate Disadvantages of:1 and inflexible . Since the operations are all objects, it is inconvenient compared to using traditional SQL statements. 3 and achieve complexity . and many complex query SQL statements are difficult to query with hibernate . Therefore, it is difficult for the program to be tuned. 3 , Big Data processing is slow . The transformation of the object model and the relationa