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Every result carries a verdict. Verified means nothing was found wrong with the run. A caveat count, shown as 1 caveat or 2 caveats, means something was found that you should know about but that does not invalidate the number. Suspect means something was found that probably does. The worst finding sets the verdict, and every finding is named, so you can decide for yourself.

A finding lowers a result. It never silently discards one.

Almost always burst versus sustained. A drive is quick for the first few seconds while its write cache absorbs everything, and slower once that cache fills. A short test can finish entirely inside the fast part and never see the slow part.

That is what the longer tests are for. The short test shows you the drive's opening burst; the long tests show you what it does after the cache fills.

Do not take the accuracy claim. Take the check. DiskDyno runs a second test whose only job is to prove the first one was not being served out of memory, and it publishes the result of that check either way. When the check fails, the app tells you the number is suspect instead of showing you a fast, wrong result.

Yes, partly, and it is worth being straight about which part. Drive-to-drive transfer testing, the 5 GB and 16 GB tests, and keeping as many saved results as you want are part of DiskDyno Pro, a one-time unlock.

The confidence verdict is not one of them. It appears on every result, on every tier, and it is never behind the paywall. Export is never restricted either.

No, and not as a policy promise. DiskDyno has no networking code of its own. Your saved results are a file on your device, and the app holds no code that could send them anywhere. Buying the Pro unlock goes through Apple, and carries nothing about your drives or your results.

The Privacy Policy sets this out in full.

Because it never scans your volumes. There is no list of your drives inside the app and no way for it to build one. You point it at one location through the standard iOS picker, and it gets access to that location and nothing else.

It is also why DiskDyno reaches drives that volume-scanning apps miss.

It writes a temporary file and deletes it. A 16 GB test writes 16 GB. Consumer SSDs are typically rated for a hundred terabytes of writes or more, so a benchmark run is a rounding error against that rating. SD and CFexpress cards are not rated this way, but a handful of test runs is still far inside normal use.

No. DiskDyno checks the free space before it starts and refuses to run if there is not room, including a safety margin. A drive-to-drive transfer test needs that space on both drives at once.

No. It measures speed, not capacity. If a drive is slower than it should be, that shows up. If a drive lies about how big it is, DiskDyno will not catch it.

There is, and it does not run on the iPad you are shooting with. The point is not carrying a laptop to a shoot to find out whether the card you just filled is trustworthy.

That measures the copy, warm cache and all, and gives you one number with no way to tell whether to believe it. It also cannot tell you which link in the chain was the slow one.

The purchase is tied to your Apple Account, not to a device. Use the restore option in the app on the other device. You will not pay again. If the restore does not take, email support@diskdyno.com.

That is DiskDyno checking that the drive is writable before offering you a test that would fail. It is written and removed immediately. If a drive is disconnected or turns read-only at the wrong moment, one can be left behind. It is inert, and any file beginning with .diskdyno- or diskdyno- is safe to delete at any time.

Refunds are handled by Apple, not by me. Go to reportaproblem.apple.com and sign in with your Apple Account. The Terms of Use cover this in section 7.