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  Roundup on Parallel Connections

A lot of blogging and follow-up discussion ensued with the announcement that IE8 supports six connections per host. The blogs I saw: IE8: The Performance Implications IE8 speeds things up IE8: 6 Connections Per Host IE 8 and Performance Testing IE8.s Connection Parallelism IE 8 Connection Parallelism Issues It’s likely that Firefox 3 will support 6 connections per server in an upcoming beta release, which means more discussion is expected. I wanted to pull all the facts into one place an...

   Browser,Concurrent connection,Persistent     2011-09-05 01:51:44

  FTP active mode and passive mode

1. What's active mode and passive mode a. FTP has two ports to control: Port 20 is for data transfer Port 21 is for control or establish TCP connection b. The process of active connection Note: C represents Client and S represents Server S opens port 20 and 21 C connects to port 21 of S with a random port, this port can be between 1024 and 65536, it sends port+x to server at the same time to specify C(X)->S(21) When S receives the command, it will sends back ACK, S(21)->C(X) S will set ...

   FTP,Active mode,Passive mode     2013-04-01 07:01:25

  Execute PHP from a .html File

How can I execute PHP code on my existing myfile.html page?:When a web page is accessed, the server checks the extension to know how to handle the page. Generally speaking if it sees a .htm or .html file, it sends it right to the browser because it doesn't have anything to process on the server. If it sees a .php extension (or .shtml, or .asp, etc), it knows that it needs to execute the appropriate code before passing it along to the browser. Here is the problem: You find the perfect ...

   PHP,HTML,PHP in HTML,AddType     2011-12-26 14:01:20

  JSON in JavaScript

When sending an AJAX request to the server, the response can have two formats : XMLHttpRequest.responseXML to access data with XML format and XMLHttpRequest.responseText to access data with string format. XML is the standard data transfer format, but one weakness is it's troublesome to parse and retrieve the data. JSON(JavaScript Object Notation) is a light weight data interchange format, we call it the JavaScript object representation. The advantage of using JSON as the data format is itself is...

   JSON,JavaScript     2013-05-04 23:25:57

  PHP buffer: output_buffering and ob_start

buffer is one piece of memory section, it is usually 4Kb in Linux. It is mainly used between different devices with different speed or different priorities. With buffer, the waiting time between different processes will be reduced. Here is one simple example, when you type something in a text editor, every time when you type a character, the operating system will not write it to the disk directly, instead it will write it to buffer first When the buffer is full, the data in the buffer will be wr...

   PHP buffer,output_buffering,ob_start     2013-06-20 22:54:15

  Transparency in Cloud Services

37signals recently launched public “Uptime Reports” for their applications (announcement). The reaction on Hacker News was rather tepid, but I think it’s a positive development, and I applaud 37signals for stepping forward. Reliability of cloud applications is a real concern, and there’s not nearly enough hard data out there. Not all products are equally reliable; even within 37signals, the new reports show a 3:1 variation in downtime across apps. That said, ...

   Cloud,Transapency,37signals,Announcement     2012-01-10 07:24:02

  How to check which Ohai plugin hangs in chef client run

Ohai plugins are very important components in chef client which aims to provide resource management automation on a server. The data discovered by Ohai plugins are describing the current state of the server and they will be used to maintain the server in a desired state. Each Ohai plugin discovers a specific pierce of information about the server such as cpu, memory, middleware etc. However, there are rare occasions(well I am a bit optimistic here) someone may find that the chef client...

   HOW TO,CHEF-CLIENT,OHAI,UPTIME,HANG     2017-12-24 22:09:59

  Web Security: In-Depth Explanation of X-XSS-Protection

What is X-XSS-Protection X-XSS-Protection is an HTTP response header designed to enable or configure built-in cross-site scripting (XSS) filters in certain versions of Internet Explorer, Chrome, and Safari. The purpose of these filters is to detect reflected XSS attacks in the response and prevent the loading of pages, thereby protecting users from such attacks. The X-XSS-Protection response header was initially introduced by Microsoft in Internet Explorer 8 to control the browser's XSS filter. ...

   X-XSS-PROTECTION,WEB SECURITY,CONTENT SECURITY POLICY,XSS,CSP     2023-11-29 01:48:40

  Some cases where MySQL cannot be started

After installing MySQL, when we try to start MySQL, sometimes we may not be able to start it. The reasons can be different. We share some general cases where MySQL cannot be started. Case 1: Directory or file permission issue If the permission is set wrongly in MySQL's $datadir and its sub directories or files, MySQL will not be able to read and write files normally. Error message: mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data /usr/local/mysql/bin/mysqld_safe: lin...

   MySQL,Error,Log     2013-08-15 03:32:36

  Taking Precautions to Avoid Shady VPN Providers

VPNs or virtual private networks are virtual tunnels that obscure your IP address, routing your internet traffic through a server located in a country of your choice, in an encrypted and anonymous way. Using a VPN allows you to: secure your sensitive data from hackers obscure the IP address so you can see content not available in your country avoid websites you routinely surf (e.g., Facebook) noticing a different IP address when you are traveling, and asking you to verify your identity bypass t...

   VPN,NETWORKING     2019-02-19 07:26:26