Computer Operating System Questions and Answers

Answer: B

Correct answer: a program that automate the translation of assembly language into machine language

An assembler reads assembly language - mnemonic operation codes and symbolic addresses - and translates it into machine code, resolving the labels to addresses as it goes. Loading the result into memory is the loader’s job, and translating a high-level language is the compiler’s.

Answer: A

Correct answer: warm

A warm boot restarts DOS without cutting the power - Ctrl + Alt + Del - so the memory test and much of the hardware initialisation are skipped and the machine comes back sooner. A cold boot starts from power-off and runs the whole self-test.

Answer: D

Correct answer: disk

A block device transfers data in fixed-size blocks and can be addressed randomly - any block read or written directly, which is why file systems are built on them. A mouse, a printer and a terminal deliver or accept a stream of characters, so they are character devices.

Answer: A

Correct answer: to improve disk performance

A block or buffer cache keeps recently used disk blocks in main memory, so a repeated read is answered without touching the disk and writes can be gathered and deferred. Since a memory access is several orders of magnitude faster than a disk access, this is where most of the gain in file system performance comes from.

Answer: B

Correct answer: load-and-go assembler

A load-and-go assembler writes the machine code straight into the memory locations where it will run, producing no object file at all. That makes it fast and convenient for short programs, at the cost of retranslating the source on every run and of being unable to link separately assembled modules.

Answer: D

Correct answer: All the above

All three are core functions of an operating system: resource management allocates the processor, devices and files among competing processes; memory management decides where each program sits and protects one from another; and error recovery handles device failures and invalid requests without bringing the system down.

Answer: B

Correct answer: External commands are stored on disk separately from COMMAND.COM

External commands are separate program files - FORMAT.COM, XCOPY.EXE and the rest - which DOS must find on disk and load before running. Internal commands are built into COMMAND.COM and are therefore always available; the external ones are unavailable if the file is missing or not on the path.

Answer: A

Correct answer: is a device that performs a sequence of operations specified by instructions in memory

A processor is the device that fetches instructions from memory and executes them in sequence, performing the arithmetic and logic they call for and directing the rest of the machine. Memory is where information is kept, and a program is the sequence of instructions it obeys.

Answer: B

Correct answer: A decision table is directly understood by the computer

A decision table sets out conditions and the actions that follow from each combination of them, which makes it easy for people to read, check and change - but it is a design document. It must still be translated into a program before a computer can act on it, so that statement is the untrue one.

Answer: D

Correct answer: saves only files that have recently changed

An incremental backup copies only the files changed since the last backup, so it runs quickly and uses little tape. The cost comes at restore time: the last full backup must be reloaded and then every incremental since it, in order.