Varieties of External Drives

The term "external drive" encompasses storage units comprising one or more hard drives housed in a distinct casing, often referred to as an "enclosure" or "box," along with its electronic module. Let's explore the different types:

Simple Devices - USB and Firewire Enclosures:

  • Basic devices relying on a single converter chip.
  • The filesystem type is dictated by the host computer to which the device is connected. For instance, connection to Windows may result in FAT or NTFS, while MacOS connections use HFS.
  • Accessed similarly to a local drive.
  • Service and maintenance tasks, such as formatting and error-checking, are handled by the host computer.
  • Power may come from a separate supply or be drawn from the PC over the data connection, a common occurrence in 2.5" USB boxes.

Complex Devices - NAS (Network Attached Storage):

  • Possess dedicated hardware, including a processor and memory, and operate with their own embedded operating system, typically Linux.
  • The filesystem type is determined by the operating system within the device, often employing the Linux ext2 filesystem.
  • Accessed over the network, either through wired or wireless connections. Some models may feature USB capabilities, but functionality still depends on the internal complexity of the device.
  • Maintenance tasks are autonomously executed by the device itself.

Hybrids:

  • Certain devices, like the Western Digital "MyBook," represent a blend of the two approaches.
  • Equipped with RAID processing capabilities but reliant on the host machine to determine the filesystem type.
  • Recovery from such devices often involves disassembling, extracting the drives, connecting them individually to a desktop PC, and performing RAID recovery, as exemplified in this hybrid NAS recovery scenario.

Understanding the distinctions among these external drive types is crucial when selecting, using, and potentially recovering data from them. Each type comes with its unique features, functionalities, and considerations, influencing their compatibility with different systems and the recovery processes involved.