Chapter 3 - Storage devices and media

Magnetic tape drives

Very thin strip of plastic coated in a magnetic layer used for storing data as magnetized or demagnetized areas.

Advantages of magnetic tape

Less expensive than HDD, huge data storage capacity, fast data transfer rate.

Disadvantages of magnetic tape

Very slow data access times, use serial access, requires use of a master tape.

Hard Disk Drives (HDD)

Common method for storing data on a computer using magnetic surfaces on multiple platters.

How HDD works

Actuators move read/write heads, platters rotate at high speeds, data is stored in concentric tracks.

Uses of fixed hard disk drives

Store operating systems software and working data/files, used in real-time systems and file servers.

Advantages of fixed hard disk drives

Fast data transfer rate and access times, large memory capacities.

Disadvantages of fixed hard disk drives

Easily damaged, many moving parts affect reliability, noisy compared to solid-state drives.

Portable hard disk drives

External HDDs connected to computers via USB ports.

Uses of portable hard disk drives

Backup systems, transferring data/files/software between computers.

Advantages of portable hard disk drives

Fast data access time and transfer rate, large memory capacity.

Disadvantages of portable hard disk drives

Easily damaged if dropped, slower data transfer rate than fixed hard drives.

CD/DVD optical disks

Read from or written to by optical storage devices, use laser light to read and write data.

Uses of CD-R and DVD-R

Home recording of music and films, storing data for later use or transfer.

Advantages of CD-R and DVD-R

Cheaper than RW disks, behave like a ROM once burned.

Disadvantages of CD-R and DVD-R

Can only be recorded once, not all players can read them.

Uses of CD-RW/DVD-RW

Record television programs, backup files and data.

Advantages of CD-RW/DVD-RW

Can be written over many times, use different file formats, less wasteful.

Disadvantages of CD-RW/DVD-RW

Relatively expensive, possible to accidentally overwrite data.

Uses of CD-ROM/DVD-ROM

Read-only memory for permanent data storage, used for music files, software, and games.

Advantages of CD-ROM/DVD-ROM

Less expensive than hard disk drives.

Disadvantages of CD-ROM/DVD-ROM

Slower data transfer rate and access time than hard disks.

Blu-ray discs

Use blue laser for read/write operations, store more data than DVDs.

Comparison of DVDs and Blu-ray discs

Blu-ray has larger storage capacity and allows for more interactivity.

Advantages of Blu-ray compared to DVD

Record high-definition TV programs, quick skipping, editing, and more.

Uses of Blu-ray discs

Home video consoles, storing and playing back movies, data storage and backup.

Advantages of Blu-ray discs

Large storage capacity, fast data transfer rate and access speed, secure encryption.

Disadvantages of Blu-ray discs

Expensive, encryption problems when used for video storage.

Solid-state drives (SSD)

Use solid-state media, more reliable and lighter than HDDs, faster data transfer speed.

Advantages of SSDs

More reliable, lighter, lower power consumption, run cooler, faster data transfer speed.

Disadvantages of SSDs

Limited write operations, not used in all servers.

Pen drives

Small portable devices using solid-state technology, used for file transfer and backup.

Uses of memory sticks/pen drives

Transporting files, backing store, security device against software piracy.

Advantages of memory sticks/pen drives

Compact and portable, robust, no additional software needed, not affected by magnetic fields.

Disadvantages of memory sticks/pen drives

Cannot write protect data, easy to lose, incorrect removal can corrupt data.

Memory cards

Solid-state technology, inserted into devices for reading or writing data.

Types of memory cards

SD cards, XD cards, CFast cards.

The future of storage devices

Cloud storage and streaming data from the internet.