Memory Management Questions and Answers

Answer: B

The memory that must be refreshed is DRAM.

Dynamic RAM stores each bit as a charge on a tiny capacitor. The charge leaks away within milliseconds, so the memory controller must read and rewrite every cell periodically, a process called refreshing. DRAM is cheap and dense, which is why it is used as main memory.

Static RAM (SRAM) stores each bit in a flip-flop that holds its state as long as power is supplied, so it needs no refresh; it is used for cache. ROM and PROM are non-volatile and keep their contents without power or refresh.

Answer: B

Cache memory exists to store frequently accessed data for faster retrieval.

Cache is a small, very fast memory placed between the processor and main memory (RAM). It keeps copies of the instructions and data the processor is likely to use again soon, so that most requests can be served without waiting for the slower main memory. This reduces the average memory access time.

Cache is volatile and tiny, so it cannot act as permanent storage for user files, which is the job of secondary storage such as disks. It does not replace main memory or secondary memory when they fill up; virtual memory and storage management deal with that.

Answer: C

Correct answer: commercial applications

COBOL was designed for business data processing: file handling, report generation and decimal arithmetic suited to money. Its verbosity is the price of the readability that made it acceptable in commerce.

Answer: D

Correct answer: user programs can implement dynamic loading without any special support from the operating system or hardware

Dynamic loading is a matter of how the program is written: the routine is loaded from disk by a library call when it is first needed. The operating system may supply libraries to make it convenient, but nothing in the hardware or the kernel is required.

Answer: A

Correct answer: cannot be done

Compaction moves a process to a different physical address, so its addresses must be recomputed. If relocation was fixed at assembly or load time the addresses are already bound and cannot be changed, so the process cannot be moved.

Answer: C

Correct answer: machine code

The object program is the translated form, which for a compiler is machine code. The compiler is what produces it, not what it is.

Answer: A

Correct answer: Process

A page may be mapped into the address space of another process, which is how two processes come to share physical memory while each keeps its own address space.

Answer: B

Correct answer: external

Paging assigns any free frame to any page, so free memory never needs to be contiguous and external fragmentation cannot arise. Internal fragmentation remains, in the last page of each process.

Answer: B

Correct answer: FOR loop

A FOR loop repeats a fixed number of times, controlled by a counter running between stated limits. WHILE and REPEAT loops repeat until a condition changes, which may be any number of times.

Answer: A

Correct answer: selection

The three constructs of structured programming come in order: sequence, then selection, then repetition. Selection is what lets an algorithm choose.