The RAW driver (RAW_DRIVER) on the Linux
system is mainly used to provide direct I/O access to block devices. As early as the mid-2000s, the RAW driver was obsolete, and for a long time, no one would recommend it. The RAW driver will be removed
with the launch of the Linux 5.14 kernel this summer.
The RAW driver allows the Linux kernel to directly provide unbuffered I/O to the block device, but it has not been used for more than ten years, because the same behavior can be achieved by using the O_DIRECT flag when opening the block device. Block devices in raw mode are exposed through /dev/raw/. Although O_DIRECT has always been the preferred method, some traditional workloads have not been maintained or the O_DIRECT method cannot be used directly. As a result, although the RAW driver has been obsolete for more than ten years, it has remained in the system during this period.
Now, the char-misc-next submission that has just entered the Linux 5.14 merge queue has finally completely removed the RAW driver. Since the RAW driver has been obsolete for many years, this submission will not have a significant impact on the system.