The defining characteristics of a block device
As discussed earlier, block devices allow far more advanced ways to handle I/O requests. Some of the defining characteristics of block devices are as follows:
- Random access: Block devices allow for random access. This means that the device can seek from one position to another.
- Block size: Block devices address and transfer data in fixed-sized blocks.
- Stackability: Block devices can be stacked through the use of the device mapper framework. This extends the basic functionalities of physical disks and allows for scaling logical volumes.
- Buffered I/O: Block devices use buffered I/O, which means that data is written to a buffer in memory before being written to the device. Read and write operations on block devices make extensive use of the page cache. Data that’s read from the block device is loaded and kept in memory for a certain period. Similarly, any data to be written to a block device is written to the cache...
