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A Web cache (or HTTP cache) is a system for optimizing the World Wide Web. It is implemented both client-side and server-side. The caching of multimedia and other files can result in less overall delay when browsing the Web. A forward cache is a cache outside the web server's network, e.g. in the client's web browser, in an ISP, or within a corporate network. A network-aware forward cache only caches heavily accessed items. A proxy server sitting between the client and web server can evaluate HTTP headers and choose whether to store web content. A reverse cache sits in front of one or more web servers, accelerating requests from the Internet and reducing peak server load. This is usually a content delivery network (CDN) that retains copies of web content at various points throughout a network. The Hypertext Transfer Protocol (HTTP) defines three basic mechanisms for controlling caches: freshness, validation, and invalidation. This is specified in the header of HTTP response messages from the server.
Freshness allows a response to be used without re-checking it on the origin server, and can be controlled by both the server and the client. For example, the Expires response header gives a date when the document becomes stale, and the Cache-Control: max-age directive tells the cache how many seconds the response is fresh for. Validation can be used to check whether a cached response is still good after it becomes stale. For example, if the response has a Last-Modified header, a cache can make a conditional request using the If-Modified-Since header to see if it has changed. The ETag (entity tag) mechanism also allows for both strong and weak validation. Invalidation is usually a side effect of another request that passes through the cache. For example, if a URL associated with a cached response subsequently gets a POST, PUT or DELETE request, the cached response will be invalidated. Many CDNs and manufacturers of network equipment have replaced this standard HTTP cache control with dynamic caching. In 1998, the DMCA added rules to the United States Code (17 U.S.C. §: 512) that exempts system operators from copyright liability for the purposes of caching. This is a list of server-side web caching software. Fountis, Yorgos (4 May 2017). "How does the browser cache work?". Messaoud, S.; Youssef, H. (2009). "An analytical model for the performance evaluation of stack-based Web cache replacement algorithms". International Journal of Communication Systems. Shinder, Thomas (2 September 2008). "Understanding Web Caching Concepts for the ISA Firewall". ISA Server. TechGenix Ltd. Erman, Jeffrey; Gerber, Alexandre; Hajiaghayi, Mohammad T.; Pei, Dan; Spatscheck, Oliver (2008). "Network-Aware Forward Caching" (PDF). Kelly, Mike; Hausenblas, Michael.
A number of Microsoft apps are included with Windows and others are available in Microsoft Store. Maps app. The Maps app provides location-based services and uses Bing services to process your searches within the Maps app. When the Maps app has access to your location, and you have enabled location-based services in Windows, when you use the “@” key to initiate a search in supported text boxes in Windows apps, Bing services collects the text you type after the “@” key to provide location-based suggestions. To learn more about these Bing-powered experiences, see the Bing section of this privacy statement. When the Maps app has access to your location, even when the app is not in use, Microsoft may collect de-identified location data from your device to improve Microsoft services. You can disable the Maps app's access to your location by turning off the location service or turning off the Maps app's access to the location service. You can keep track of your favorite places and recent map searches in the Maps app.
Your favorite places and search history will be included as search suggestions. If you grant the Maps app access to your camera, you’ll be able to capture the location of where your photos took place - for instance, a photo of your car will also tell you where your car is parked. You can also share your location with other people in your contacts. If you're signed in with your Microsoft account, your favorite places, search history, and certain app settings will be synced across other devices and services. For more information, see the Sync and backup settings section of this privacy statement. Camera app. If you allow the Camera app to use your location, location data is embedded in the photos and videos you take with your device. Other descriptive data, such as camera model and the date that the picture or video was taken, is also embedded in photos and videos. If you choose to share a photo or video, any embedded data will be accessible to the people and services you share with.
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