Portable SSD
A portable SSD for work that moves between machines
A portable drive is judged on the slowest link in a chain of four — the drive, its bridge, the cable and the port it lands in — and the number on the box describes only the first. The second decision is encryption, because a drive that travels is a drive that gets left behind.
By Jean-Benoit Buisson
The chain that decides the rate you actually see
Four things sit between your file and the flash, and the slowest one governs.
The port on the machine. Sockets of the same shape carry very different rates depending on the generation behind them, and a laptop a few years old frequently has a port a generation or two below the drive.
The cable. Shape does not imply capability. A cable rated only for charging will connect the drive and hold it back, and a cable of unknown provenance is the least visible bottleneck in the chain.
The bridge inside the case, which converts between the drive’s own interface and the host connection. It is rarely quoted, and it is the reason two enclosures around identical drives can differ.
The drive itself, which is what the number on the box describes.
The practical consequence is that a drive quoting a high figure into an older port delivers what the port allows. That is not a defective product; it is the specification being read without the rest of the chain.
Burst and sustained are different numbers
Solid-state drives generally write quickly for a while and then settle to a lower rate once a faster region is consumed. For copying a folder of documents this never appears. For moving a video project or a whole photograph library it appears every time.
Where the maker publishes what happens under sustained writing, that is the figure describing a large transfer. Where only a peak is published, treat it as a peak.
Small files behave differently again: thousands of tiny items take far longer than their total size suggests, on any drive, because the overhead is per file rather than per byte.
Encryption is the decision to make on day one
A portable drive is, by design, the drive most likely to be left on a train. Encrypting it is the difference between losing a piece of hardware and losing what was on it, and it is also what makes retiring the drive simple years later — discard the key and the contents are unreadable regardless of what remains in the flash.
Two things to check before committing. Whether the method you choose can be opened on every machine you need it on, since something that only one operating system understands will fail you on a borrowed computer. And where the drive itself offers hardware encryption or a fingerprint reader, what the maker publishes about how the key is held and what happens if the hardware fails.
Keep the key or passphrase somewhere independent of the drive. A key that lives only on the thing it protects is not a key.
Ruggedness, and what the rating actually says
Cases sold as rugged publish specific claims: an ingress rating against dust and water, a drop specification naming a height and a surface, sometimes a crush figure. Each is a tested condition, published by the maker, and each is worth reading rather than summarising as “tough”.
What none of them cover is the file you were writing at the moment of the event, or the drive being lost, or the drive being stolen. A rugged case reduces one category of accident; the copy that lives elsewhere is what covers the rest.
Buy for the working set that travels rather than for the archive, which belongs on something larger and cheaper per terabyte at home. Leave headroom, for the same internal reasons that apply to any solid-state drive.
The maker publishes capacity in its own unit. A machine that displays in units of 1024 shows a different figure for the same hardware, and nothing has gone missing between the shop and the desk. Compare drives in one unit and plan against the maker’s number.
A portable drive is not the copy, unless you make it one
Carrying the only version of a project on a drive that travels is the arrangement most likely to end badly, because everything that makes it portable also makes it losable.
Where the portable drive is genuinely the second copy of something, treat it as one: keep it somewhere other than beside the machine it copies, and check occasionally that what is on it opens.
