Case file · Logical & corruption · MKD-2025-4311
One Cyclic Redundancy Check, One Life's Work.
The Toshiba had lived on a USB dock in the yard office for years. After a power cut it turned awkward: every large copy stopped on the same words — cyclic redundancy check
— single files at first, then entire folders. He swapped the cable, tried the office laptop, and ran the Windows check twice, which took all night
. What sat on it was the working memory of a Grand Union narrowboat fitter: every drawing and cut list for thirty years of boats
.
Same fault? Start here.
0800 6890668
Without the jargon.
The phrase reads like a software fault, which is exactly why it fools people. A cyclic redundancy check is a receipt: the drive handed something over, and it no longer matched the sum written next to it. A scrambled filesystem on a sound disk produces that. So does a surface losing its grip on what was recorded there. The two want opposite treatment, and choosing wrongly is not free. Windows will keep asking a weak patch until it gives in or gives out, and the overnight check he ran twice was two nights of exactly that.
The kit this job needed.
See how a job runs here →| Kit | Why it was used | What it gives us |
|---|---|---|
| DeepSpar Disk Imager 4 | Copied the Toshiba to a fixed allowance of retries, soft areas logged and deferred | Maps the heads, then images each — resets, timeouts and power cycles controlled |
| R-Studio Technician | All rebuilding was done on the copy, never on the disk | Copes with almost any file system; dependable array rebuilds |
| ACE Lab PC-3000 Express | Asked the firmware first — attribute history, grown defect table, and the long sessions it had logged | Talks to drives in each maker's own command set, beyond what standard ATA covers |
What happened on the bench.
Let the drive's own counters name the fault
Not a sector was copied until the drive had been questioned at firmware level, and the counters answered plainly. Reallocations were high and rising, with a queue of sectors pending. Two enormous power-on sessions stood in the log, matching the nights he left the Windows check running. A surface giving up, then, not a filesystem in knots.
Ration the retries; they are a finite budget
Imaging rules were fixed before the first pass: short timeouts, a hard ceiling on attempts, anything stubborn logged and stepped over rather than fought. Difficult zones got their own brief visits right at the end. The sums are the point here. Winning one awkward sector by force can cost you the thousand healthy ones queued behind it.
Work on the image and leave the drive unplugged
With the copy taken, the Toshiba was never powered again. On the image the news improved: the directory tree had survived, and the losses clustered where the weak zone crossed a run of scanned sheets. Every casualty was written down by filename — a list of drawings, not a vague apology — so he could see precisely which sheets the surface had kept back.
The outcome.
He had said on the phone which folder mattered — steelwork drawings for boats still afloat — and that folder was verified before anyone mentioned money. A fresh disk carried the archive home, complete but for the listed scans. Two he can redo from paper in the yard. The rest belonged to boats built before his time, and their paper is long gone.
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Also filed under Logical & corruption.
Does that sound like your device?
One lesson runs through the lot: cut the power, let us look for free, then decide with the facts in hand.