What mode of operation allows only one program to be in use at any time?

What mode of operation allows only one program to be in use at any time?

• A. Single-tasking
• B. Multitasking
• C. Multi-user
• D. Parallel processing

Answer: (A)

Single-tasking means the system runs only one program at a time. The CPU dedicates itself to that single program until it finishes or blocks for input/output, so no other program gets CPU time until control is returned. This contrasts with multitasking, where the system quickly switches between programs to give the illusion that many run at once. It also differs from multi-user setups, where multiple users can be active on the same system, and from parallel processing, which uses multiple processors to perform several tasks simultaneously.

Single-tasking means the system runs only one program at a time. The CPU dedicates itself to that single program until it finishes or blocks for input/output, so no other program gets CPU time until control is returned. This contrasts with multitasking, where the system quickly switches between programs to give the illusion that many run at once. It also differs from multi-user setups, where multiple users can be active on the same system, and from parallel processing, which uses multiple processors to perform several tasks simultaneously.