Features
The general purpose of a hard drive is the type of devices for which it was originally intended.
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For PC. Hard drives designed for use with conventional consumer computers and laptops. At the same time, the possibility of installing an internal HDD (see "Performance") directly depends on the form factor (see the relevant paragraph), while external models are not subject to such restrictions — it is enough for them to have the appropriate connection connector. Also note that almost all external hard drives are designed specifically for PCs; making server models external is not technically justified.
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For the server. Hard drives designed for servers have increased speed and reliability, because they constantly have to receive and give large amounts of information. To ensure speed, they may provide an increased rotation speed (up to 15,000 rpm). Such drives are made only internal (see "Performance"), and, in addition to SATA, they can use other, more specific connection methods — for example,
SAS(see "Connection interfaces").
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For game console. Specialized hard drives designed for use with game consoles. They are made only external (see "Performance"), they are intended mainly for storing games — including saves and user settings profiles. The main difference between such devices and classic external HDDs is
...precisely the optimization for working with game consoles, including the availability of special software tools for improved integration. Many of these drives are originally designed for a specific model or family of set-top boxes.Manufacturer's warranty
Manufacturer's warranty provided for this model.
In fact, this is the minimum service life promised by the manufacturer, subject to the rules of operation. Most often, the actual service life of the device is much longer than the guaranteed one.
Interface
— SATA. Nowadays, it is the most popular interface for connecting internal hard drives.
the first version of SATA provides data transfer rates of about 1.2 Gbps,
SATA 2 has a practical data transfer rate of about 2.4 Gbps (300 MB / s), and the most advanced generation of
SATA 3 has a speed of 4.8 Gbps (600 Mbps)
eSATA. Modification of the SATA interface, designed to connect external hard drives; not compatible with internal SATA. The practical data transfer rate is similar to SATA 2 at about 2.4 Gbps (300 Mbps).
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USB 2.0. The earliest of the USB standards found in modern hard drives — and exclusively external (see "Performance"). Provides connection to a traditional full-size USB port, provides data transfer rates up to 480 Mbps, as well as a rather low power supply, which is why drives with this type of connection often require additional power. In light of all this, and the advent of the more advanced USB 3.2 standard (see below), USB 2.0 is considered obsolete today and is extremely rare, mainly in inexpensive and early models of drives. However, a drive with this interface can also be connected to a newer USB port — the main thing is that the connectors match.
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USB 3.2 gen1(previously USB 3.1 gen1 and USB 3.0). The standard for connecting external HDDs, which replaced the
...USB 2.0 described above. Uses a traditional full-size USB connector, delivers data transfer speeds up to 4.8 Gbps (600 Mbps) and higher power ratings, making these drives easier to handle without external power. However, for the same reason, you need to be careful when connecting USB 3.2 gen1 drives to older USB 2.0 connectors — such a connector may not have enough power to power a newer drive.
— USB 3.2 gen2. Further development of the USB 3.2 standard (formerly known as USB 3.1 gen2 and USB 3.1). The maximum data transfer rate in this version has been increased to 10 Gbps, and the power supply can reach 100 W (supporting USB Power Delivery technology). At the same time, drives with this type of connection can also work with earlier versions of full-size USB connectors — the main thing is that there is enough power.
— USB-C 3.2 gen1(formerly USB-C 3.1 gen1 and USB-C 3.0). USB Type-C connection compliant with USB 3.2 gen1 capabilities. These features are described in more detail above, the difference from the “regular” USB 3.2 gen1 in this case lies only in the type of connector: this is a relatively small (slightly larger than microUSB) socket, which also has a double-sided design. Due to its compact size, USB-C is found both in full-sized PCs and laptops, and in compact gadgets like smartphones and tablets; some drives with this connection are initially capable of "mobile" use.
— USB-C 3.2 gen2(formerly USB-C 3.1 gen2 and USB-C 3.1). Updating and improving the USB-C 3.2 gen1 described above — the same USB-C connector and increased data transfer rate to 10 Gbps (as in the "regular" USB 3.2 gen2).
— IEEE 1394. Also commonly known as "FireWire". A universal connector, similar in capabilities to USB 2.0 (see above), but used much less often, and nowadays is practically obsolete.
— Thunderbolt. High-speed interface for connecting external peripherals. It is used mainly in Apple computers and laptops, although it is also found in equipment from other manufacturers. Note that in modern HDDs there are mainly two versions of Thunderbolt, which differ not only in speed, but also in connector: Thunderbolt v2(up to 20 Gbps) uses a miniDisplayPort plug, and Thunderbolt v3(up to 40 Gbps) — USB type C plug (see above). Thus, in some hard drives, USB-C and Thunderbolt connections are implemented through a single hardware connector, which automatically detects which computer input the device is connected to.
— S.A.S. Modification of the SCSI interface, provides data transfer rates up to 6 Gbps (750 Mb / s). It is used mainly in servers, in desktop PCs and laptops it is practically not used.
— Fibre Channel. Professional high-speed interface primarily used in server drives ("Purpose"); similar in many ways to SAS. Allows "hot" replacement of drives; the actual data transfer rate over Fibre Channel, depending on the version, can reach 12.8 Gbps.Cache memory
The amount of internal hard drive memory. This memory is an intermediate link between the high-speed computer RAM and the relatively slow mechanics responsible for reading and writing information on disk platters. In particular, the buffer is used to store the most frequently requested data from the disk — thus, the access time to them is reduced.
Technically, the size of the buffer affects the speed of the hard drive — the larger the buffer, the faster the drive. However, this influence is rather insignificant, and at the level of human perception, a significant difference in performance is noticeable only when the buffer size of the two drives differs many times — for example,
8 MB and
64 MB.
Data transfer rate
The speed of data transfer between the disk and client devices is determined by the type of drive, spindle speed, memory buffer size and connection connectors. The last parameter is the most important, since it is impossible to exceed the bandwidth of a particular interface.
Plates
The number of platters provided in the design of the hard drive.
Physically, a hard disk consists of one or more platters, on which information is recorded. Several plates can be provided in order to achieve the desired volume without increasing the form factor. At the same time, it is also necessary to install an appropriate number of reading heads in such a drive, which complicates the design, reduces its reliability, and increases the cost. Therefore, manufacturers choose the number of plates based on a reasonable compromise between these points, and for selection, this parameter is more of a reference than practically significant.
Operation power consumption
The amount of power consumed by the disk when reading and writing information. In fact, this is the peak power consumption, it is in these modes that the drive consumes the most energy.
HDD power consumption data is needed primarily to calculate the overall system power consumption and power supply requirements for the system. In addition, for laptops that are planned to be used often "in isolation from outlets", it is advisable to choose more economical drives.
Standby power consumption
The amount of power consumed by the disk "idle". In the on state, the disk platters rotate regardless of whether information is being written or read or not — maintaining this rotation takes the energy consumed while waiting.
The lower the power consumption while waiting, the more economical the disk is, the less energy it consumes. At the same time, we note that in fact this parameter is relevant mainly when choosing a drive for a laptop, when energy efficiency is crucial. For stationary PCs, “idle” power consumption does not play a special role, and when calculating the requirements for a power supply, it is necessary to take into account not this indicator, but the power consumption during operation (see above).
MTBF
Guaranteed (minimum) hard drive uptime. The longer the time between failures, the more durable and reliable the device. At the same time, we note that after this time, the drive will not necessarily fail immediately — most models remain operational even after the claimed resource has been exhausted, but the manufacturer does not give any guarantees here.
