Computer Science - Cpu

Front 1

What does CPU stand for?

Back 1

Central Processing Unit.

Front 2

What does ALU stand for?

Back 2

Arithmetic and Logic Unit

Front 3

What does IAS stand for?

Back 3

Immediate Access Storage

Front 4

How much is one petaflop?

Back 4

1,000 trillion calculations per second.

Front 5

What is a bus?

Back 5

A bus is a minature parallel wire/cable that is connected to both the CPU and other hardware components. Data can be transferred and sent to and from these places.

Front 6

Name three types of buses.

Back 6

Address Buses, Data Buses, Control Buses.

Front 7

Describe the functions of three types of buses.

Back 7

• Address Bus: this is used to set up which memory address the CPU is linked to for a read/write operation
• Data Buses: These exchange data between a memory address and the CPU when read’write operation is carried out.
• Control Bus: These transfer command codes + return signals between the components of the CPU and the external devices.

Front 8

Describe the Fetch Process.

Back 8

The CPU fetches data and instructions from a memory address. These instructions are then sotred on the Current instruction register, and the address of the instruction is then sotred on the Program Counter (PC).

Front 9

What is a register?

Back 9

A register is an internal temporary memeory area that is close to the CPU. It is extremely quick and therefore is compatible to the CPU's fast speeds.

Front 10

What is the second process of the cycle, what is involved here?

Back 10

The second part of the cycle is to decode the data that has been fetched by the CPU. The CPU has to identify the operation code as part of the instruction which tells it which operation to perform. If it requires the CPU to act on data, then the second part of the instruction will contain the data or the memory address where the data is stored.

Front 11

What is the third step of the process, what is involved here?

Back 11

The third part of the cycle is the execute area.This is the area in which the data can finally be processed. The instruction is carried out and the information about this process is stored in another register. Depending on the instruction, a number of things can be done. For example, if a calculation needs to be carried out, then the data bus will be used to pass the data onto the ALU as input, and then it will be passed back as output.

Front 12

What are the three main jobs of the Control Unit?

Back 12

The three main jobs of the control unit are to control and monitor the hardware (to make sure that the commands given to the control unit by the application software are used), to control the input and output of data (so that signals go out at the right time to the right place), and to control the flow of data (it controls the cycle).

Front 13

What is used instead of a backing store to store data?

Back 13

The CPU may store the data in the Immediate Access store for programs that are needed instantly. This is an area for temporary data that may be needed for the Control Unit instantly. Data is stored here instead of the Backing Storage (such as the Hard disk) area because data that is saved here is much too slow to allow application to run directly. The CPU needs to store data and programs in the IAS otherwise the process would be far too slow if it was stored in the Backing Storage, as it cannot run application directly at a pace that is quick enough compared to the internal temporary register – the Immediate Access Store.

Front 14

What are the parts of the ALU?

Back 14

The parts of the ALU are as follows: ---The logic area: which deals with the logic and the comparison of data ( such as whether a value is equal to, greater than or less than another) --- The arithmetic area: which deals with any necessary calculations of the data.