Storage slots
The number of separate slots for drives provided in the design of the pocket, in other words, the number of drives for which this model is designed.
In addition to models for
one slot, nowadays you can find more capacious solutions — for
two drives, or even
more. Such "multiplying" is found in three types of devices. The first is large-format pockets for stationary purposes (see above), operating in the format of separate storages for a large amount of data. Such models may support RAID arrays (see above) and other special features. The second type of devices with more than one slot are separate docking stations (see "Type") with similar functionality. The third type is server models (see "Purpose") with an internal installation; they again allow the organization of arrays, but by means of the server itself.
Note that external devices with one slot can be powered from the USB port, but several drives in this case inevitably require a separate PSU (see "Power").
Max. drive size
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.
