Internal and external storage. Types of storage devices

Any electronic computers include memory storage. Without them, the operator could not save the result of their work or copy to another medium.

Punch cards

At the beginning of the emergence of computer technology for the storage of information , punched cards were used - ordinary cardboard cards with digital marking applied.

On one punch card, 80 columns were placed, one bit of information could be stored in each column. The holes in these columns corresponded to one. The data was read in sequence. It was impossible to record anything on a punch card again, so they needed a huge amount. To store a 1 GB data set, it would take 22 tons of paper.

A similar principle was also used in punched tapes. They were wound around a reel, took up less space, but were often broken and did not allow adding and editing data.

Floppy disks

The advent of floppy disks became a real breakthrough in information technology. Compact, capacious, they allowed to store from 300 KB on the earliest samples to 1.44 MB on the latest versions. Reading and writing were done on a magnetic disk enclosed in a plastic case.

The main drawback of floppy disks was the fragility of the information stored on them. They were vulnerable to the effects of electromagnetic fields and could be demagnetized even in public transport - a trolleybus or tram, so they tried not to use them for long-term storage. The diskettes were read in the drives. In the beginning, there were 5-inch floppy disks, then they were replaced by more convenient 3-inch floppy disks.

The main rival of floppy disks were flash drives. Their only drawback was the price, but with the development of microelectronics, the cost of flash drives fell dramatically and the diskettes went down in history. Finally, their release stopped in 2011.

Streamers

Streamers were used to store archival data. They looked like videotapes externally and on the principle of action. The magnetic tape and two reels allowed to sequentially read and write information. The capacity of these devices was up to 100 MB. Mass storage of such drives have not been received. Ordinary users preferred to store their data on hard disks, and it was more convenient to keep music, movies, programs on CD- and later DVD-disks.

CD and DVD

These storage devices are still used. An active, reflective and protective layer is applied to the plastic substrate. Information from the disk is read by a laser beam. The standard disk has a capacity of 700 MB. This is sufficient for example to record a 2-hour film in an average quality. There are also two-sided discs when the active layer is deposited on both sides of the disc. To save a small amount of information, a mini-CD is used. Drivers, instructions to computer products are now written on them.

DVDs came to replace the CD in 1996. They allowed you to store information already 4.7 GB. The advantage of them was that the DVD-drive could read both CD and DVD-disks. At the moment this is the most massive memory drive.

Flash Drives

The CD and DVD drives discussed above have a number of advantages - cheapness, reliability, the ability to store large amounts of information, but they are designed for write-once. You can not make changes to the recorded disc, add or delete extra. And then a fundamentally different drive - flash memory - comes to our aid.

For some time he competed with floppy disks, but quickly won in this race. The main deterrent was price, but now it was reduced to an acceptable level. Modern computers are no longer equipped with disk drives, so the flash drive has become an indispensable companion for all dealing with computer equipment. The maximum amount of information that fits on the USB flash drive reaches 1 Tb.

Memory cards

Telephones, cameras, e-books, photo frames and much more require memory drives for work. Due to their relatively large size, USB drives are not suitable for this purpose. Memory cards are specially created for such cases. In fact, this is the same flash drive, but adapted for small-sized products. Most of the time, the memory card is in the electronic device and is removed only to transfer the accumulated data to a permanent medium.

There are many standards of memory cards, the smallest of them have a size of 14 by 12 mm. On modern computers, instead of a drive, a card reader is usually installed, which allows you to read most types of memory cards.

Hard disks (HDD)

Memory storage for a computer is a hard disk. Inside it there are metal plates, covered on both sides by a magnetic composition. The engine rotates them at a speed of 5400 for old models or 7200 rpm for modern devices. The magnetic head moves from the center of the disk to its edge and allows you to read and write information. The amount of hard drive depends on the number of disks in it. Modern models allow storing up to 8 Tb of information.

Disadvantages of this type of memory drives is almost none - these are very reliable and durable products. The cost of a unit of memory in hard disks is the cheapest among all types of drives.

Solid State Drives (SSDs)

No matter how good the hard drives were, they almost reached their ceiling. Their speed depends on the speed of rotation of disks, and its further increase leads to physical deformation. Flash technology, which is used in the manufacture of solid-state memory drives, is devoid of these drawbacks. They do not contain moving parts, therefore they are not subject to physical deterioration, are not afraid of shock impacts and do not make noise.

But so far there are serious shortcomings. First of all, the price. The cost of a solid-state disk is 5 times higher than a hard disk of a similar size. Another significant drawback is a short service life. Solid-state drives are usually chosen to install the operating system, and a hard disk is used to store data. The cost of solid-state drives is steadily declining, there is progress in increasing their resource. In the near future they should displace traditional hard disks, as in time the flash drives replaced floppy disks.

External storage

Internal storage and internal memory are all good, but often you need to transfer information from one computer to another. Back in 1995, a USB interface was developed that allows you to connect a wide variety of devices to your PC, and memory drives are no exception. At first they were flash drives, later there were DVD-players with a USB-connector, and finally, HDD and SSD.

The appeal of the USB interface in its simplicity is enough to stick a USB flash drive or other drive and it is possible to work without the need for driver installation or other additional actions. The development of the interface and the appearance in the beginning of USB 2.0, and then USB 3.0, dramatically increased the data exchange rate for this channel. The speed of the external disk now differs little from the internal one, and their size can not but rejoice. External memory drive easily fits in the palm of your hand, while it allows you to store hundreds of gigabytes of information.