SLR03 - Input, output, and storage

Input device

Device that allows information to pass from outside into computer system

Output device

Device that takes data stored digital format and convert other format

Storage device

Any device used for either temporary/permanent storage of data

Drive

Device that reads & writes data from secondary storage

Media

What data actually stored on

Optical storage

• Read/writes using laser which is shone onto a reflective surface

• Lands and pits store 0s and 1s

Optical storage positives

• Cheap

• Lightweight

• Portable

Optical storage negatives

• Slow access times

• Prone to scratches

Magnetic storage

• Read/writes using magnetism

• North and south polarity store 0s and 1s

Magnetic storage positives

• Cheap to buy

• Large capacity

Magnetic storage negatives

• Slow access times

• Fragile

Solid state

• Reads/writes using flow of electricity forcing electrons into floating gates between two oxide layers

• Causes change in charge = 0s and 1s

Solid state positives

• Durable

• Fast access time

Solid state negatives

• Cost

• Limited read/write

ROM

• Small piece of read only memory located on motherboard

• Non-volatile

• Contains first instructions for computer

RAM

• Temp storage of instructions & data

• Holds information being executed by processor

• Volatile

• Much faster than hard disk

Why ROM needed?

Contains bootstrap that performs POST (power on self test)

Send signals to all connected components, wakes them up and makes CPU aware of them so OS can be loaded from secondary storage

Virtual storage

Often referred to as cloud storage, concept of storing and retrieving data over internet in cloud instead of local storage device

Virtual storage advantages

• Data access any time on any device as long as internet access

• Data can easily shared without need for removable media transfer

• Easier to collaborate

• Storage considered to be limitless from users perspective

Virtual storage disadvantages

• Can be expensive

• If connectivity poor, access times slow

• No internet connection means no access to files