Comp Sci - Secondary Storage Devices

Secondary Storage Devices

What represents binary data on a hard disk in magnetic storage?

Tiny magnetised regions where the magnetic orientation in one direction represents 0, and the other direction represents 1.

How is data read from a hard disk in magnetic storage?

The read/write head is moved to be over the correct track while the platter/disk spins around. A whole sector/block is read in one go by the read/write head.

What is the process of reading data from optical storage?

The disk rotates at high speed, the laser head moves across the radius of the disk, and the laser shines onto the disk. Tiny indentations (pits) and bumps reflect light differently compared to lands (flats). The reflected light is interpreted into 1s and 0s representing data stored on the disk.

How is data structured on an optical storage disk?

Data is stored on a single spiral track rather than concentric tracks.

How is binary data stored in solid-state storage?

In solid-state storage devices, binary data is stored in a similar way to RAM, but solid-state drives are non-volatile, so the data remains when powered down.

What does random access mean in the context of solid-state devices?

It means that the data can be accessed in any order and there is no seek time required, unlike magnetic hard drives or optical discs.

What are memory modules in solid-state devices?

What are memory modules in solid-state devices?

What are the typical uses of magnetic storage?

Desktop computers to store large files, programs, and operating systems.

What is the capacity range of magnetic storage?

750GB to 3TB (3000GB) large.

What are the read/write speeds of magnetic storage?

High read/write speeds.

What is the portability status of hard disks in magnetic storage?

Heavy with poor portability; even external ones are clunky.

What is the durability of magnetic storage like?

Dropping this device could cause damage, especially to the read head.

What is the reliability of magnetic storage?

Can be used again and again but does have a limited life; a good few years.

What is the cost of magnetic storage?

Low cost; quite cheap.

What are the typical uses of optical storage?

Storage of small media files and documents.

What is the capacity of a standard CD-ROM in optical storage?

650MB.

What are the read/write speeds of optical storage?

Moderate read/write speeds.

What is the portability status of optical storage?

Very portable and lightweight.

What is the durability of optical storage like?

Fair durability; can survive the odd knock, but scratches can damage the data.

What is the reliability of CD-Rs and CD-RWs?

CD-Rs are write once but can be read over and over. CD-RW can be reused.

What is the cost of optical storage?

Very cheap.

What are the typical uses of solid-state flash storage?

Used in desktop computers, laptops, and tablets to store large files, programs, and operating systems.

What is the capacity range of solid-state drives?

64GB to 480GB, moderate.

What are the read/write speeds of solid-state drives?

Super fast read/write.

What is the portability status of solid-state drives?

Very portable; small and lightweight.

What is the durability of solid-state drives?

No moving parts so can survive knocks and scrapes.

What is the reliability of solid-state drives?

Can be reused many times, up to 100,000 times.

What is the cost of solid-state drives?

Very expensive per GB.

What are the typical uses of flash storage in phones and cameras?

Great choice as no moving parts so mobile devices can function whilst on the move.

What is the capacity range of flash storage in portable devices?

16GB to 64GB.

What are the read/write speeds of flash storage?

Super fast read/write.

What is the portability status of flash storage?

Extremely portable; small and lightweight.

What is the durability of flash storage?

No moving parts so can survive knocks and scrapes.

What is the reliability of flash storage?

Can be reused many times, up to 100,000 times.

What is the cost of flash storage?

Expensive per GB.

What are the typical uses of cloud storage?

Used to store documents and media files online.

What is the capacity of cloud storage?

Unlimited, providing you can pay for it.

How does network bandwidth affect cloud storage speeds?

Depends on network bandwidth speeds; poor bandwidth can cause uploading and downloading of large files to take a long time.

What is the portability status of cloud storage?

It is virtual so you don't have anything physical to move around.

What is the durability of cloud storage?

Providing you keep up payments and the company looks after their storage.

What are the reliability aspects of cloud storage?

Devices are very durable and reliable; companies often back up storage devices in many places.

What legal issues can arise with cloud storage?

A company's data may be stored in a country which doesn't follow the same data protection laws.

What are the potential risks associated with cloud storage?

The hosting company could be attacked by hackers who could steal your data.

What is the cost of cloud storage?

Can be expensive depending on the service, but often it is free for a few GBs.