What is the primary role of a RAID controller?

What is the primary role of a RAID controller?

• A. It provides nonvolatile storage for the RAID cache.
• B. It manages an array of physical disk drives and presents them to the computer as logical units.
• C. It controls network routing for storage traffic.
• D. It formats disks using a proprietary protocol.

Answer: (B)

The core idea is that a RAID controller coordinates multiple physical disks and makes them appear to the computer as one or more logical drives. It sits between the host and the disks, deciding how data is laid out across the drives according to the RAID level in use (striping, mirroring, parity), handling build and rebuild operations when a drive fails, and managing cache to speed I/O. By presenting logical units to the operating system, it lets software format and use storage as if it were a single or a few drives, while the controller handles the complexity of the underlying disk arrangement. Other functions described are features or separate tasks rather than the primary role: caching is a performance aid rather than the main purpose, network routing isn’t about storage management, and disks aren’t formatted with a proprietary protocol to fulfill the RAID role.

The core idea is that a RAID controller coordinates multiple physical disks and makes them appear to the computer as one or more logical drives. It sits between the host and the disks, deciding how data is laid out across the drives according to the RAID level in use (striping, mirroring, parity), handling build and rebuild operations when a drive fails, and managing cache to speed I/O. By presenting logical units to the operating system, it lets software format and use storage as if it were a single or a few drives, while the controller handles the complexity of the underlying disk arrangement.

Other functions described are features or separate tasks rather than the primary role: caching is a performance aid rather than the main purpose, network routing isn’t about storage management, and disks aren’t formatted with a proprietary protocol to fulfill the RAID role.