The iStorage diskAshur DT is a step away from the usual portable secure drives we’ve tested. Portable storage is usually operated by plugging directly into a host desktop or laptop PC, to take power over that machine’s USB bus.
This limits storage capacity to a few tens or hundreds of gigabytes, depending on whether solid-state flash memory or notebook-sized hard disks are used. The latter can now be found in up to 1TB capacity.
Put a desktop-class 3.5in SATA disk inside though, and capacity ceilings can quadruple with today’s disk technology. In the case of the diskAshur DT, iStorage offers three capacity options of 1TB, 2TB or 3TB.
The disadvantage is of course size, weight and power. Where a portable drive with 2.5in disk inside will weigh around 200g, the diskAshur is more brick-like in its dimensions, and weighty too at almost 1.2kg.
Also factor in the awkward external power supply, another 158g for mobile users to carry, and which will clutter the desk with added wiring.
But aside from raw capacity, you can expect fast data access too, as we confirmed in our benchmark tests.
iStorage diskAshur DT 3TB: Operation
Number keypads are a fitting way to lock down encrypted hard drives. In contrast to software-based solutions, they have better longevity in the field, and can be more secure too.
Software encryption on a PC is often tied to specific platforms (notwithstanding popular cross-platform solutions such as open-source TrueCrypt), so sharing secure documents between Mac and Windows, for example, is either problematic or impossible.
Even when cross-platform security solutions are offered, there is the risk of obsolescence – for example where a USB flashdrive hosts the unlock software. While it may be designed to work with today’s PC operating systems, there’s no guarantee it will still work in one or two OS upgrades’ time.
But from a simple security point of view, software encryption typically enquires a passphrase or code to be entered on your computer. And that will be the weakest link, when that machine is compromised by a keylogger or other spyware that can record the longest of passwords.
For the diskAshur DT, the encryption is achieved in a hardware chip inside the unit, and passcodes are entered only through the drive’s own keypad, reducing the chances of your code getting hacked.
The internal chipset deters brute-force attacks by adding a delay before incorrect PIN attemtpts can be retyped.
The diskAshur DT can be very easy to use, and the Quick Start instructions cover the creation of a single admin PIN code; delve deeper and you’ll find a number of features such as separate user codes, self-destructe codes and auto-timeout lock that can be set through arcane key presses signalled with an array of different flashing LEDs to administrate the device.
There’s still some elementary setup required out of the box though, with 0 and Lock key held together to enter admin mode, then 9 and Lock together after a new PIN has been entered. PIN codes can be between six and 16 numbers.
Used at its simplest by one person, the drive will simply unlock and mount on a connected PC after the PIN and Lock key are entered.
iStorage diskAshur DT 3TB: Build quality
The diskAshur DT unit is very well constructed from extruded aluminium, finished with a tough-feeling black paint. A perforated front plate allows natural ventilation, with no additional fan to add noise to a relatively quiet SATA disk inside.
Buttons are rubber-topped and have a confident click action. Telephone-style alphabet characters are added to each key to simplify the construction of PIN codes based on more memorable words or phrases.
Data connection is through a USB 3.0 Type B port on the rear, and a Kensington lock slot on the back provides basic security against casual theft.
iStorage diskAshur DT 3TB: Performance
We tested the 3TB version of the iStorage diskAshur DTand recorded superb read/write performance.
In the Blackmagic Disk Speed test, sequential read speeds hit 140MBps, and writes of 150MBps. QuickBench showed similar large-file results, peaking at 155MBps reads with 4MB-size file, and 158MBps writes with 2MB files. Average across the range 2-10MB, read/writes measured 143 and 149MBps respectively.
Down at the small file level, sequential read/writes averaged 100 and 104MBps, while random read/writes still averaged decent scores of 24 and 45MBps.
The diskAshur DT is a very speedy external hard disk that does not appear to be in any way hampered by its on-the-fly 256-bit hardware encryption.