Surely, every user of a personal computer uses various storage devices, such as flash drives, disks, etc. Unfortunately, not everyone knows what exactly these devices represent external memory.
What is External Memory?
External memory should be understood as a kind of personal computer memory, which is implemented using various external equipment capable of storing a large amount of information for a long time. An external storage device, in comparison with the internal memory of a computer, for example, random access memory, has a large volume, but at the same time a low data transfer rate.
External memory specifications and devices
There are a huge number of external storage devices today. In relation to a personal computer, they can be: hard disks (both external and internal), floppy disks, which are intended exclusively for reading and writing, laser disks, streamers, flash cards, etc. All these devices are shared between by the type of access to information. These can be: direct access devices, as well as serial access devices. They are separated by the fact that in devices of direct access, the time of access to information does not depend on its location on the carrier, and in devices of sequential access, such a dependence exists. The amount of memory on hard drives (both external and internal) can reach several terabytes. The volume of floppy disk drives usually does not exceed 1.44 MB (today they are practically not used). CD-drives have a capacity of 640 megabytes, while DVDs have capacities up to 17 gigabytes. The maximum amount of USB-drives today reaches 64 GB.
As for the main characteristics of external memory, these are their information capacity, speed, reliability of data storage, as well as cost. Capacity should be understood as the maximum amount of information that can be recorded on the device. It should be noted that, as a rule, it is much larger than the capacity of the internal memory. Unfortunately, the speed or performance of such devices is many times inferior to internal memory devices. It is determined by the time of access, recording and reading of information that is stored on the device. In terms of reliability, this parameter is almost identical to the internal memory. Reliability can only be compromised in case of improper or careless use of external memory devices, as well as in the presence of various malicious software.
