OCR A-Level Computer Science Computer systems and architecture overview quiz quiz

The Program Counter (PC)

The Memory Data Register (MDR)

The Current Instruction Register (CIR)

The Accumulator (ACC)

The MDR

The MAR

The CIR

The ACC

$20$

$2 \times 20$

$2^{20}$

$20^{2}$

The address bus

The control bus only

None of them

The data bus

It overlaps the fetch, decode and execute stages of consecutive instructions

It increases the clock speed of the processor so every single instruction runs faster

It adds more levels of cache so that data can be fetched from memory more quickly

It reduces the number of processor cores needed to run several programs at once

A large set of complex, variable-length instructions handled directly in hardware

A small set of simple, fixed-length instructions

It cannot be pipelined at all because its instructions overlap one another

It always uses considerably more power than an equivalent CISC processor would

Running a single-threaded program full of branches and complex control flow

Managing the operating system's file system and scheduling the running processes

Highly data-parallel work such as matrix arithmetic and graphics

Permanently storing the bootstrap loader so the machine can start up from cold

Optical storage, which uses a laser to read pits

Solid-state storage, which uses flash memory cells

ROM, which stores firmware permanently in chips

Magnetic hard disk drive

RAM is volatile read/write memory; ROM is non-volatile

RAM is non-volatile and keeps its contents on power-off, while ROM is volatile and loses them

Both RAM and ROM are volatile, so both of them lose all of their contents when the power is off

ROM is volatile read/write memory that holds the running operating system while the machine is on

In the cache

On the stack

In ROM

In the accumulator

It always minimises the average waiting time across every process in the ready queue

It never causes any context-switch overhead, no matter how short the time quantum is set

It gives each process a fair time slice, keeping interactive tasks responsive

It always runs the shortest job first, so short tasks never wait behind longer ones

A web browser used to view and navigate pages on the world wide web

A spreadsheet program for entering data and performing calculations

A photo editor for adjusting and retouching digital photographs

A disk defragmentation utility