Computer & IT

note!Answer: B) random access memory
In random access memory any location can be reached in about the same short time once its address is given.

note!Answer: C) memory data register
The Memory Data Register (MDR) holds the data being written to or read from the addressed memory location.

note!Answer: D) program counter
The program counter stores the address of the next instruction to be fetched and executed.

note!Answer: D) register
The accumulator is a special-purpose register that holds operands and results of arithmetic and logic operations.

note!Answer: D) both b and c
Magnetic tapes, disks and magnetic bubble memories retain data without power, so they are non-volatile.

note!Answer: A) RAM
RAM is volatile, meaning it loses its contents when power is switched off.

note!Answer: A) ROM
ROM is programmed by the manufacturer during fabrication with fixed contents.

note!Answer: D) PROM
PROM is non-volatile and can be programmed only once by the user.

note!Answer: C) semiconductor memories are used as mass memory medium
Semiconductor memories are used as primary memory, not as mass storage; mass storage uses magnetic or optical media.

note!Answer: B) semiconductor memory
Semiconductor memory has the fastest access time among the listed memory types.

note!Answer: B) track
Data on a magnetic disk is stored in concentric circular tracks; sectors divide each track.

note!Answer: B) the octal representation 46
Grouping 100110 into 3-bit groups gives 100 110 = 4 6 in octal. Its decimal value is 38, not 46.

note!Answer: A) A + B
A̅B + AB = B, so the expression becomes B + AB̅ = A + B by the absorption law.

note!Answer: C) -128
An 8-bit 2's complement number ranges from -128 to +127, so the most negative value is -128.

note!Answer: C) the original number
Taking the 2's complement twice restores the original number.

note!Answer: C) A
A(A+B) = AA + AB = A + AB = A by the absorption law.

note!Answer: C) not a protocol
The OSI model is a conceptual reference framework, not a protocol itself; protocols are implemented within its layers.

note!Answer: C) user data
A data packet consists of a header followed by the user data (payload).

note!Answer: A) seventh layer
The application layer is the topmost, seventh layer of the OSI model.

note!Answer: B) circuit switching
Circuit switching sets up a dedicated end-to-end channel between two stations for the duration of the call.