What is Web Caching?
Web Caching The most common cause of web pages not updating once you have uploaded new files to your hosting space is caching. Caching is used widely across the Internet to cut down the amount of time it takes to request information. It works by keeping a temporary copy of information that has been requested locally for a defined amount of time. The most common forms of caching web pages occur with your web browser and Internet Service Provider (ISP). Most web browsers cache pages when you visit a web site so that the next time you go to that page it appears to load faster, because it is using a local copy rather than requesting a new copy be sent across the Internet. ISP caching works in much the same way once you have visited a website your ISP may cache those pages so that they appear to load faster the next time you visit them. The main problem with this is that unlike your browser cache you can not delete these temporary files, instead you have to wait until your ISPs cache expire
Cache (memory) is memory that is stored very close to the CPU, say on the same chip as the CPU, to allow fast access. Similarly, a disk cache is memory that is used to store frequently accessed disk pages for fast access. Web caching is the storage of Web objects near the user to allow fast access, thus improving the user experience of the Web surfer. Examples of some Web objects are Web pages (the HTML itself), images in Web pages, etc. Web objects can be cached locally on the user’s computer or on a server on the Web. There are several types of caches for Web objects: • Browser cache: Browsers’ cache Web objects on the user’s machine. A browser first looks for objects in its cache before requesting them from the website. Caching frequently used Web objects speeds up Web surfing. For example, I often use google.com and yahoo.com. If their logos and navigation bars are stored in my browser’s cache, then the browser will pick them up from the cache and will not have to get them from the
Web cache engines store Web pages that are frequently requested by users. Users do not actually get Web pages directly from Web sites, but rather from the caching computer. Caching computers feed pages to users either from pages that have already been stored, or by accessing Web sites to retrieve new pages which are then passed on to the user.
