Question

1. Space-multiplexed sharing is the division of a resource into two or more distinct units and then the allocation of the individual units to processes. Time-multiplexed sharing is when one process can use the entire resource for a period of time and then another process uses it at a later time. Identify the following as either space-multiplexed sharing or time-multiplexed sharing. Can the usage of some resources be both space-multiplexed sharing and time-multiplexed sharing depending on the resource is used?

1. The land in a residential subdivision
2. A personal computer
3. A whiteboard in a classroom
4. A bench seat on a bus
5. A single-user file in UNIX
6. A printer on a timesharing system
7. The heap in the C/C++ runtime system

Answer 1

• The land in a residential subdivision (space-multiplexed sharing)
• A personal computer (space-multiplexed sharing)
• A whiteboard in a classroom (space-multiplexed sharing)
• A bench seat on a bus (space-multiplexed sharing)

• A single-user file in UNI ( time-multiplexed sharing )
• A printer on a time sharing system ( time-multiplexed sharing )
• The heap in the C/C++ runtime system ( time-multiplexed sharing )

Typically the resource is shared or multiplexed between the users. This can take the form of time-multiplexing, where the users take turns (e.g., the processor resource) or space-multiplexing, where each user gets a part of the resource (e.g., a disk drive).