Give two reasons why caches are useful. What problems do they solve? What problems do they cause? If a cache can be made as large as the device for which it is caching (for instance, a cache as large as a disk), why not make it that large and eliminate the device?
The cache is a special storage space for temporary files that makes a device, browser, or app run faster and more efficiently. Generally, when the user tries to open any file, the file is shifted from secondary storage to the main memory and then the file is opened. If the file is already in the cache then the time taken to open the file is far less than the file opened from the secondary storage. For instance, in file explorer, the recent files are stored in the cache.
After opening an app or website for the first time, a cache stashes files, images, and other pertinent data on your device. Cache data is used to quickly load an app or website for each and every subsequent visit.
- Cache solves the problem of slow data access
- Cache reduces the load on slow physical devices.
However, some problems are caused by the cache.
- They cause consistency problems because the real data might be different from the data in the cache. For instance, while using the WhatsApp web, as soon as we open, all the messages and media files are displayed on the screen without taking much time. This is possible due to the cache. Our computer stores the data of our WhatsApp during our previous access. However, there are a few messages and media which are not yet loaded leading to data inconsistency.
- Making a cache as large as the device may be useful if it can be made fast. However, the device is still needed to store data when the power is turned off.