Punched Media: Cards and Tape
Introduced as early as 1725, the punched card was the go to system for controlling automated machinery or processing data until the introduction of magnetic-based storage media in the 1950s. The Punched Card presented data and commands by the inclusion or absence of punched holes in predefined locations. With the introduction of IBM general-purpose computers in the 1950s, punched cards were used for both data input and storage. The most commonly produced punch card is said to have held the equivalent of 70 bytes of information.
The sister to Punched Cards, Punched Tape, originally began as connected Punched Cards and eventually evolved into a roll of paper with 6, 7, or 8 rows of punched and non-punched area. Most often used by tailors and communication technologies, Punched Tape was often used in Minicomputers and as a data transfer technology for ROM and EPROM programming.
Both Punched Cards and Tape fell out of favor in the ensuing decades after the introduction of newer storage technologies.
Magnetic Storage: Tape and Drums
Magnetic Tape storage systems use a narrow strip of plastic film or metal with a thin magnetic coating that records data using the changes in intensity and polarity of electricity. Originally based upon a comparable technology called magnetic wire recording, Magnetic Tape storage has gone on to become a versatile storage media still used today in audio recordings and some video recordings.
The first introduction of magnetic tape storage systems came with the arrival of the UNIVAC computer in 1951. The UNISERVO was capable of up to 128 bits of data per square inch on its metal tape that was 1200 feet long. This gave the UNISERVO an approximate total storage capability of 1843200 bits or 230.4 Kilobytes (0.2304 Megabytes).
At the same time that Magnetic Tape storage systems gained a foothold, Magnetic Drum memory began to be used as a working memory system for computers. The Magnetic Drum memory was an early precursor to Hard Drives as it used heads to read the memory stored on the drum. The data was recorded to the drum, much like Magnetic Tapes, with a ferromagnetic recording coating. The total storage capacity of the Magnetic Drum system was only a few thousand Bytes, depending upon the diameter and length of the drum. The Magnetic Drum system could still be found in use as late as the 1980s and in current-day UNIX machines, the default virtual memory is named /drum.
The Hard Disk storage system was designed to be a bridge between the working memory of a computer and the long-term storage options of Magnetic Tape. In 1953, IBM created such a system and included it with the RAMAC computer in 1956. The first Hard Disk drive was comprised of 50 2-foot diameter platters and was contained in a space nearly the size of two refrigerators.
The basic mechanics of the Hard Disk drive have remained the same since the introduction of the “flying head” and consists of a spinning disk (known as a platter), which is coated with a magnetic material and a magnetic head which move on an actuator arm that reads the stored data. The benefit of the Hard Disk storage system is that data can be stored or read in any order rather an sequentially, greatly increasing data access times.
Hard Disk drives are still a popular form of data storage technology today. Whereas the RAMAC hard disk drive had a total storage capacity of 5 Megabytes, current commercial grade high-capacity Hard Disk drives can store as much as 6TB (or 6,000,000 Megabytes).
Floppy Disks are a storage system that consists of a thin disk of magnetic storage medium, normally a flexible material with a magnetically-responsive coating, housed within a flexible rectangular casing lined and lined with a fabric designed to remove dust particles during use. The Floppy Disk inserts into a Floppy Disk drive, which at first could only read data stored on the Floppy Disk. The ability to write came later in the life-cycle of the Floppy Disk storage system.
Floppy Disks first became available in 1971 as an 8-inch disk and, as microcomputers become more popular, the 5.25-inch and 3.5-inch Floppy form factors were introduced. The first 8-inch floppy disks were capable of storing approximately 80 Kilobytes (or 0.08 Megabytes), while the ultimate form of the Floppy Disk storage system, the 3.5-inch Superdisk, were capable of storing upwards of 240 Megabytes.
Current PC manufacturers no longer include support for native Floppy Drive storage systems beyond external USB adaptors and products.
Optical data storage systems are based upon the Optical Disc, which is a flat, circular disk that encodes binary data in the form of pits on its surface. The Disc is comprised of multiple layers that include a reflective layer, a diffuse substrate layer of plastic, and an encoding layer that contains the pits. Data on an Optical Disc is read with the use of a laser diode that registers the distortion of light created by the surface pits when the disc is spun in the drive.
The first Optical Discs to be made available commercially appeared in 1972 with the release of the 12-inch Laserdisc and this product was quickly followed to market by the audio compact disc in 1982. Later that same decade, CD-ROMs began to appear and quickly supplanted the Floppy Disk as the primary medium to storage and disseminate digital data, like operating systems and programs.
Optical Storage systems have continued to advance with the introduction of second-generation systems, including the DVD, and third-generation systems, which included Blue-ray Discs and HD DVD discs. With each successive generation, storage capabilities increased from the initial CD-ROM capacity of approximately 700 Megabytes, to the DVD capacity of approximately 4.7 Gigabytes (4,700 Megabytes), to the current generation of Blue-ray discs that store upwards of over 300 Gigabytes (300,000 megabytes).
Flash storage systems are a form of non-volatile memory that resembles logic gates that also provide their name, like NAND flash or NOR. Flash memory gained its name from the first incarnation of the technology, designed by Toshiba that required stored data to be "flashed" with a bright UV light in order to erase it. This process required the entire memory to be erased at one time. The current most popular version, NAND flash, uses floating-gate transistors designed to trap electrons in a binary state and allows for portions, or blocks, of data to be erased at a time.Flash storage comes in many different shapes and sizes, including but not limited to Memory Sticks, MultiMediaCard, MicroSD, miniSD, Secure Digital cards, solid state drives, and USB thumb drives. While the initial capacity of the Toshiba Flash memory was 2 Megabytes, current capacities depend upon application and type.
Cloud storage is a distributed storage model that replaces local hardware with digital pools of data, located on remote hardware that can span multiple servers and locations. Cloud storage is normally provide by a host company responsible to maintaining access and availability as well as local physical security. Many operating systems and service providers now allow for 5 to 15 Gigabytes of free cloud storage as well as the ability to expand beyond the initial offering for a fee.
As technology has shrunk and moved into a more mobility-based model, the need to provide safe and secure remote access to data on capacity-restricted or cross-platform devices has become a major priority and has driven the expansion of cloud storage offerings.