Computer Technology – Data Storage Devices
Secure data storage and strategies to achieve it have become increasingly important for both individuals and businesses. Technical innovations have brought improved storage media to a wide range of users.
Data storage must meet high technological standards. Increasingly, devices are required to store large amounts of data securely for long periods of time. The storage medium should be compact and transportable, allow quick access, and connect with many systems-all at an attractive price.
Standard mobile storage media
Floppy disks and Zip disks have been largely replaced by compact discs with read-only memory (CD-ROMs). More efficient digital versatile discs (DVDs) have been available since 1996. Blu-ray discs (BD) are the latest generation, offering up to 50 GB of storage.
Flash memory drives with a USB connection are double-sided devices with a faster access time. These drives can be connected to almost all computer systems without any special reading device. Flash memory can be electronically erased and reprogrammed. Flash drives may have a capacity of many gigabytes, and are small and simple to handle.
Storage media with special tasks
In the computer motherboard’s primary storage or main memory, data is temporarily saved for immediate processing. Graphic and video cards also have their own main memory. BIOS is a kind of permanent memory in which the manufacturer stores important system data.
This data cannot normally be modified by the user. Random-access memory (RAM) allows faster data transfers than storage devices such as the hard drive, however in most cases, the data is lost once the computer powers down. New forms of RAM may allow for powerless data retention.
New technologies
More efficient materials and novel ideas for data storage are now being researched. A team in Japan are investigating an optical storage medium using tiny plastic balls, 500 nanometers in diameter, with a fluorescent colorant. Each ball is modified during saving so that the colorant lights up during reading.
Every ball represents one bit. This method would provide several times as much memory as a DVD in a comparable amount of space. Data has even been transferred onto DNA molecules and implanted into bacteria in the form of genetic information.
The data remains unmodified and readable even after the bacteria has reproduced hundreds of times. It remains to be seen whether this ambitious research will ever result in a marketable product.
PHYSICS OF DATA STORAGE
To store binary data, storage material needs two forms—to represent and 1. A hard disk has magnetic units, polarized to represent or 1. The smallest units of a USB memory stick are tiny transistors that conduct or block current.
CD-ROMs have one-bit indentations, scanned by a laser. In magnetooptical disks, a laser changes the state of the magnetic material on the disk.
BASICS
BITS, the smallest memory unit, have one of two values (0 or 1), represented by positive and negative charges.
TO ENCODE 1 keyboard character, bits are grouped into a byte, usually in groups of 8. Since 2^8 = 256, the 8 bits can have 256 possible combinations.
1 MEGABYTE usually equals 1 million bytes. However, since computer memory systems are based on powers of two. 1 megabyte = 2^20 = 1,048,576 bytes.