Computer - creado desde un Mapa Mental

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Input/Output

Processor

Memory

Input Devices

Output Devices

Speed Mismatch

Keyboard

Mouse

Barcode Reader

Optical Character Reader (OCR)

Optical Mark Reader (OMR)

Scanner

Graphics Tablet

Microphone

Displays

Printers

Graphics Plotter

Speakers

Difference between operating speeds of different parts of a computer system

Solution: Buffers

Central Processing Unit (CU)

Arithmetic_Logic Unit (ALU)

Manage instructions

Tells other parts of the processor what they should do to carry out the instruction

Syncrhonises the actions of the processor using signals from its internal clock

Decides which instruction is the next to be carried out and fetches it

Decodes instructions to work out what needs to be done to execute them

Allows arithmetic to add numbers together

Performs logical comparisons

Acts as a gateway between the processor and the other parts of the computer system

Inputs and outputs (data) wait in ALU until the CU decides what to do with it

Inside the processor

Outside the processor

Registers

Small pieces of memory inside the processor that allows quick access to data stored into main memory

PC

CIR

ACC

MAR

MDR

Primary Storage

Secondary Storage

Main Memory = Primary Memory = Immediate Access Store (IAS) Memory

Cache Memory

RAM (Random Access Memory)

Used to store data that is the most likely to be needed again to the microprocessor

Cache Memory

Includes all instructions and data needed to be carried out

Features

Types

Read from/Written to memory

Volatile memory

Can be accessed at any location independently of which previous location was used

Dynamic RAM (DRAM)

Static RAM (SRAM)

Needs to be regularly recharged

Less expensive to make

Store more bits per chip

Less power to operate

Used to construct main memory

Measured in GB

Shorter access of time

Used to construct...

Faster than DRAM

Measured in MB

Read-Only Memory (ROM)

Magnetic Media

Optical Media

Solid State Media

Contents cannot be altered (non written memory)

Non-volatile memory

Small Capacity

Updates are not allowed in the memory

Loads the operating system from the hard drive so that the computer can work

Check starting routines to allow a computer to be switched on and works everyday

Special case (Embedded Microprocessors)

Types

USed in applications such as a washing machine or a burglar alarm system.

ROM contains all the firmware of the computer system

Programmable Read Only Memory (PROM)

Erasable Programmable Read Only Memory (EPROM)

Electrically Erasable Programmable Read Only Memory (EEPROM)

Data can be stored once

Is manufactured as a black memory / ROM is programmed during the manufacturing process

used to stora data or programs that are going to be used with no changes required)

Can be erased with UV light

Can be reprogrammed

Can be rewritten using a special device called PROM reader

Requires electricity to be erased

Special type: flash memory

Can be rewritten whilst is in the computer

Flash Memory

Magnetic Tape

Hard Disk Drive (HDD)

Compact Disk (CD)

Digital Video Display (DVD)

Blu-Ray

CD-ROM

CD-R

CD-RW

DVD-R

DVD-RW

DVD-RAM

Solid State Drive (SSD)

USB Sticks