Comparison Dynamode DM-CAD-S8 vs Maiwo K3082

The general purpose of the pocket.

Note that for different types of such accessories (see above), a different division is used according to purpose. So, external pockets are divided into portable and stationary, and internal pockets are divided into laptop models, PC chassis and server solutions. For docking stations and cases, this parameter is not specified at all: the former initially assume stationary use, the latter, again, are portable by definition.

Here is a more detailed description of the options relevant for external pockets:

— Portable. Models designed for frequent moving from place to place and even for use on the go (for example, connecting to a laptop on the road). Most modern external pockets fall into this category — after all, initially external drives (which such pockets are an alternative to) are also made predominantly portable. The specific features of these accessories may vary, but they are all quite compact and designed for only one internal drive, and they receive energy from the same USB port they are connected to (see "Power").

— Stationary. External pockets designed to stay in one place all the time and do not involve frequent movement and use on the road. Such models are much less common than portable ones; most of them are rather l...arge designs, designed to install 2 or more drives, and are often a kind of "NAS-server without networking". However, there are also models for 1 slot — they usually differ from portable counterparts in the presence of a stand that allows you to put the pocket vertically (so that it takes up less space on the table), and is powered by a power supply unit.

In turn, internal pockets for different purposes have the following specifics:

— For laptops. This type is usually designed to install 2.5" or M.2 form factor drives in the optical drive bay (CD / DVD) — due to the compact size of laptops, this is often the only possible way to install an additional drive.

— Chassis. Pockets designed for regular desktop PCs. Note that the term "chassis" traditionally refers to only one special kind of such pockets — the so-called Mobile Rack, colloquially known as "sled". The main function of such accessories is to provide the ability to quickly move drives from one case to another. To do this, the design provides for two parts: a base, which is mounted in a 5.25" slot on the case, and a removable cartridge, into which the drive is installed directly. To prevent theft or unauthorized physical access, the "sled" can be equipped with a lock that blocks the removal of the drive. Our time is used quite rarely, mainly when working with disk arrays, as well as in some other specific cases — for example, so that after the end of the working day you can take a disk with materials with you or hide it in a safe to ensure confidentiality.
Another kind of PC pockets are adapters for installing drives in non-standard seats. The classic case is the use of a 2.5" laptop drive in a 3.5" desktop case, but nowadays there is a more specific option — the use of an SSD M.2 drive as a PCI-E expansion card (for more details, see "Form factor") .

— For the server. Server systems most often have to deal with large volumes of information that require high reliability and/or speed of access. Thus, most pockets of this purpose are designed for several drives (from two to six) — this allows you to provide the necessary volumes and, if necessary, organize a RAID array of one or another level. At the same time, built-in support for RAID (see below) is not found in such devices — it is easier and more reasonable to organize it using the server itself. It is also worth noting that according to the method of installing disks, such pockets usually refer to “sleds” (see “Chassis” above) — this provides additional convenience, allowing, for example, quickly replacing a failed drive in a RAID array. Server pockets can use specialized connection interfaces like SAS, although traditional SATA is still more popular.

Drive interface provided in the design of the pocket, in other words, a way to connect the drive.

It makes sense to use pockets for internal drives, so the appropriate interfaces are used for connection. Also note that in internal models (see "Type") the interface of the drive is often not specified, since it corresponds to the interface for connecting the pocket itself to the computer. As for specific options, here are the most relevant for today:

— SATA 3. The newest and most advanced, and in storage pockets, the most common version of the SATA interface. This interface is designed for internal storage, primarily hard drives; for SSD, it is relatively poorly suited, since it does not allow realizing all the potential of solid-state memory. Specifically, SATA 3 provides data transfer rates up to 600 MB / s, while earlier SATA drives can also be connected to such connectors — unless the connection speed is limited by the capabilities of a slower interface.
It is worth saying that in addition to traditional 2.5" and 3.5" SATA drives (see "Form factor") connected via the connector of the same name, nowadays you can also find M.2 form factor SSD modules that also use a SATA format connection . Such models are noticeably inferior in speed to solutions for M.2 PCI-E, but they are also cheaper. They are connected to the M.2 socket, which must support SATA.

— SATA 2. The predecessor of the SATA 3 described above; this version allows you to t...ransfer data at speeds up to 300 Mbps. In pockets, it is much less common, mainly among outdated models — for example, external solutions using USB 2.0 (see "Connection").

— PCI-E. A variant found exclusively on M.2 drive models (see Drive Form Factor). Such modules use the M.2 connector, the connection through which is most often implemented in the PCI-E format. At the same time, the specifications, usually, specify the version and number of PCI-E lines — the supported speeds directly depend on this. For example, the marking "PCI-E 3.0 2x" means 2 lines of PCI-E version 3.0; this version provides 984 Mbps per lane, so the overall speed is about 1.97 GB/s. However, nowadays, more advanced options are more common — for example, PCI-E 3.0 4x, where the speed is already about 3.9 Gbps. At the same time, drives and pockets with different versions and the number of PCI-E lanes in this case are usually compatible with each other, except that the speed will be limited by the capabilities of a slower interface.

— SATA/SAS. Models that support connection via two interfaces — SATA or SAS. The latter is a specialized standard used primarily in server systems; pockets with this feature also have a corresponding purpose. And this versatility is achieved due to the fact that SAS controllers are also compatible with SATA drives, so you can provide both types of connectors in your pocket. At the same time, SAS noticeably outperforms SATA in terms of operating speed — it is up to 22.5 Gbps, depending on the version (against a maximum of 6 Gbps in SATA). However, note that the SAS interface does not have a strictly defined type of connector — several types of plugs can be used for such a connection; this point needs to be specified separately.

The maximum storage capacity supported by the pocket. In models with multiple disks/SSDs (see "Drive Slots"), this item indicates the largest total volume supported by the device; by dividing this capacity by the number of slots, you can determine the maximum allowable capacity of each individual drive.

The limitation on the maximum volume is relevant mainly for external models, including docking stations (see "Type"). This is due to the fact that fundamentally different interfaces are used for the drive and for connecting the pocket itself in such models (most often SATA and USB, respectively, see above for details). For the normal interaction of such interfaces, an electronic controller is required; and the larger the volume of the installed drive (s) — the higher the requirements for the performance of such a controller.

Note that, other things being equal, supporting large volumes is more expensive, and capacious drives themselves are not cheap. Therefore, when choosing according to this indicator, it is worth considering real needs, and not chasing the maximum numbers.

The type of power provided in the design of the pocket.

This parameter is relevant only for external models (in internal solutions, power is determined solely by the connection interface). The options could be:

— USB. Powered by the same USB port used for the main connection. The advantage of this option is obvious: it allows you to do without unnecessary wires and use the pocket regardless of the presence of sockets (which is important, for example, when working with a laptop on the road). At the same time, the power of USB power is generally low, and besides, it directly depends on the version of the connector (see "Connection"). So for pockets with several disks, this option is not suitable in principle. In other cases, you should pay attention to compatibility when connecting to a USB connector of an older version than is supported by the pocket. For example, a model with USB 3.2 gen1 can be physically connected to a USB 2.0 port without any problems, but it may not have enough power for normal operation. However, more modern versions (USB 3.2 gen1 and gen2) practically do not have such compatibility problems.

- Power Supply. Powered by a separate PSU, usually plugged into a power outlet. These pockets are bulkier and less mobile than USB-powered models, they can't work without power outlets nearby, and the extra wire is a bit of a hassle. On the other hand, the power supply is capable of delivering mor...e power than USB, and this power is constant and does not depend on the version of the port to which the drive is connected. So many stationary models use just such a power supply; and for external pockets for two or more drives, this is generally the only available option.