secondary storage

Secondary storage (also known as external memory or auxiliary storage), differs from primary storage in that it is not directly accessible by the CPU. The computer usually uses its input/output channels to access secondary storage and transfers the desired data using intermediate area in primary storage. Secondary storage does not lose the data when the device is powered down—it is non-volatile.
Types of storage devices

How the read-write head is applied on the floppy

Floppy Drive - Usually holds about 1.44 MB of storage. Use a floppy disk media.

Floppy disk on wikipedia

Super Drive
The LS120 or SuperDisk is a drive which supports a special floppy diskette which can store up to 120MB or 240MB of information as well as being backwards compatible and still supporting the standard floppy diskettes.

Zip Drive
New generation similar to the floppy disk drive created by Iomega The Iomega Zip Drive was first released 1994. Zip Drives Disks come in 100MB, 250MB and 750MB

Optic Drive CD Burner An optical storage device that holds data anywhere from 650MB to 700MB (74-80 minutes)
Dvd Burner - A newer optical storage device that holds data anywhere from 4.70-17.08GB DVD Capacity DVD-5 4.7GB (2 hours) DVD-9 8.54GB (4 hours) DVD-10 9.4GB (4.5 hours) DVD-18 17.08GB (8 hours)
Newest DVD format
Blu-Ray DVD 25-50GB HD-DVD 15-30GB

Hard drive - A hard drive is usually built inside your computer and holds anywhere from 1GB to 4TB of capacity. Operating system installed in internal hard drives. There are three types of internal hard drives are PATA, SATA and SCSI.

Difference between SSD and Magnetic hard drive

Solid State Drive(SSD)
uses integrated circuit assemblies as memory to store data persistently. SSD technology uses electronic interfaces compatible with traditional block input/output (I/O) hard disk drives.SSDs are typically less susceptible to physical shock, are silent, and have lower access time and latency.

Portable hard discs
Portable hard discs is hard discs that can be used to store and backup file.Portable hard discs is used to transport files and backup data from computer to computer. Greatly improved data cargo carrying capacity (relative to the 1.44 Mb floppy disc). External hard drives comes in USB, Firewire, SATA and SCSI. Easily damage if dropped. Shock resistance is especially important for mobile devices. Some laptops and portable hard discs now include active hard drive protection that parks the disk heads if the machine is dropped, hopefully before impact, to offer the greatest possible chance of survival in such an event. Maximum shock tolerance to date is 350 g for operating and 1,000 g for non-operating.

Memory sticks/Pen drives
USB flash drives are typically removable and rewritable, much smaller than a floppy disk. Storage capacities typically range from 64 MB to 64 GB. USB flash drives offer potential advantages over other portable storage devices, particularly the floppy disk. They have a more compact shape, operate faster, hold much more data, have a more durable design, and operate more reliably due to their lack of moving parts. Flash drives are widely used to transport files and backup data from computer to computer.

Flash memory cards
A memory card or flash memory card is a solid-state electronic flash memory data storage device used with digital cameras, handheld and Mobile computers, telephones, music players, video game consoles, and other electronics. Nowadays, most new PCs have built-in slots for a variety of memory cards; Memory Stick, CompactFlash, SD, etc. Some digital gadgets support more than one memory card to ensure compatibility.

Magnetic tapeMagnetic tape has been used for data storage for over 50 years. When storing large amounts of data, tape can be substantially less expensive than disk or other data storage options. Tape storage has always been used with large computer systems. Modern usage is primarily as a high capacity medium for backups and archives.

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