In recent years, the problem of choosing a convenient information storage device has become increasingly relevant. Famous CDs, first appearing in 1982, have come a long and glorious path of development. Initially, such a disk could store 700 MB of data (the first models with 650 MB quickly evolved). With the growth of software distributions, more capacious disks were required - this is how DVDs appeared. Currently, Blu-ray technology with its 25 GB or more capacity is becoming more popular. But more and more often it is believed that the development of compact discs for the tasks of backup and storage of information will end there, giving way to solid-state media. This is not always obvious, but laptop owners are especially closely monitoring progress in this area. Replacing a CD drive or installing an additional hard drive inside the system unit of a personal computer is not difficult. But in laptops, everything is not so simple. In the usual way, you cannot put a second hard drive on a laptop, because the components are located very densely inside the case and there is no free space.
However, with the development of the USB bus, quite a few devices have appeared, including an external hard drive for a laptop. Unlike the usual varieties for internal installation, such hard drives (HDD) have a USB interface that supports “hot” connection / disconnection of devices (which was not, for example, on the IDE). Connecting a laptop hard drive is easy: just plug the USB cable from the HDD into any available port on the laptop. As a result, the operating system will determine the fact of the connection and, if there is already a file system on the disk, it will automatically assign a letter, allowing you to work with the device. When choosing an external USB drive, it is recommended to pay attention to the way of organizing power. Some models use a USB bus to communicate with a laptop, but a small external unit for power supply, which is less convenient. Others do not require such a unit, being content with 500 mA from the port (or 1 A, in case of using Y-Cable). Nevertheless, it is worth noting that models with a power supply often have higher speed and capacity. An external HDD is most often used as a backup storage of important data or a portable device (remember CDs).
Hard drive for laptop and computer (PC) are selected in different ways. If for PCs the main criterion is performance and capacity, then for portable models, energy efficiency is added to the list. After all, a mobile computer must run on battery power for a long time, which is why a laptop hard drive almost never happens with 10,000 spindle speeds. Such a solution would be very wasteful in terms of battery power consumption.
When purchasing an internal hard drive for a laptop, you need to determine the type of interface. At the moment there are two of them: IDE and SATA. They are not compatible with each other, so the interface of the HDD and the controller on the motherboard should correspond.
Spindle Speed (RPM) determines productivity, heating and energy consumption. The fastest models are at 7200 rpm, the compromise option is 5400, and the slowest (less and less common) are 4200. The higher the rotation speed, the greater the heating and energy consumption.
One of the characteristics of a hard drive is the amount of cache memory. The bigger it is, the better.
Currently, there are hard drives based on solid state flash memory. They do not have moving mechanical parts, they have a low level of energy consumption, they are light in weight, and their speed characteristics are approaching (and even surpassing) analogs with magnetic disks inside. One of the disadvantages is the high cost.