Shulou(Shulou.com)06/02 Report--

What is the difference between pages and blocks? A block is the smallest unit of data that an operating system can either write to a file or read from a file.

What exactly is a page? Pages are used by some operating systems instead of blocks. A page is basically a virtual block. And, pages have a fixed size-4K and 2K are the most commonly used sizes. So, the two key points to remember about pages is that they are virtual blocks and they have fixed sizes.

Why pages may be used instead of blocks Pages are used because they make processing easier when there are many storage devices, because each device may support a different block size. With pages the operating system can deal with just a fixed size page, rather than try to figure out how to deal with blocks that are all different sizes. So, pages act as sort of a middleman between operating systems and hardware drivers, which translate the pages to the appropriate blocks. But, both pages and blocks are used as a unit of data storage.

Http://www.programmerinterview.com/index.php/database-sql/page-versus-block/

To sum up, devices like disks are called block devices because the basic unit of data transmission is Block. Even if your target data is only one character in the file, the operating system and driver will still read the whole block and give you the target data you want, and the rest of the data in the block will be saved in a specific buffer/cache.

The size of the block is not necessarily the same on different operating systems.

Data is transferred between disk and memory in blocks rather than specific bytes that users need, and data stored in memory is managed in the form of pages. Of course, assembly instructions only know byte addresses.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.