1. Storage Management
- OS provides uniform, logical view of information storage
- abstracts physical properties to logical storage unit (file)
- each medium is controlled by device (i.e., disk drive, tape drive)
- varying properties include access speed, capacity, data-transfer rate, access method (sequential or random)
- File system management
- files usually organized into directories
- access control on most file systems to determine who can access what
- OS activities include
- creating and deleting files and directories
- primitives to manipulate files and dirs
- mapping files onto secondary storage
- backup files onto stable (non-volatile) storage media
2. Storage-Device Hierarchy
3. Caching
- Important principle, performed at many levels in a computer (in hardware, operating system, software)
- Information in use copied from slower to faster storage temporarily
- Faster storage (cache) checked first to determine if information is there
- if it is, information used directly from the cache (first)
- if not, data copied to cache and used there
- Cache smaller than storage being cached
- cache management important design problem
- cache size and replacement policy