21. The data bus in 8080A/8085 microprocessor is a group of

A. eight bidirectional lines that are used to transfer 8 bits between the microprocessor and its I/O and memory
B. sixteen bidirectional lines that are used for data transfer between the microprocessor and memory
C. eight unidirectional lines that are used for I/O devices
D. eight lines used to transfer data among the registers
E. None of the above

22. Control of computer system or subsystem operation by an operator who may intervene at arbitrary times is

A. Manual control
B. Mapping
C. Shift register
D. ALU
E. None of the above

23. In which of the following terminals the screen is regarded as an array of pixels, where each pixel is either on or off?

A. Character map terminal
B. Bit map terminal
C. RS-232 C terminal
D. All of the above
E. None of the above

24. Which language has been selected as the basis for the Japanese “fifth generation” computers.

A. ALGOL
B. COBOL
C. PROLOG
D. C
E. None of the above

25. A notation for defining the form and structure of data is known as

A. Data description language
B. Binary language
C. Data channel
D. Data definition language
E. None of the above