PCs & notebooks · case notes · ADR-2025-2876
Short Reads Passed. The Long One Never Finished.
Half-way through transferring his own files, he found the 4TB Seagate had become very slow to boot up
, and transferring files takes hours rather than minutes
; in fact some transfers never finished, because it will disconnect itself during transfer
, and it had frozen the computer into a restart. He was only able to safely move about 25%
of his total amount of information. The remaining three quarters was why he decided to stop and ask us.
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What failed, and why.
Short tests do not ask a disk the same question as a long test does. Short tests hit a few counters, compare those counters against pre-set limits that are large enough to allow for failure margin, and return a pass. Worn-out drives clear short tests easily. Long tests cross the entire surface of a disk and continue to read across that surface. Failing drives show their problems clearly when performing long tests: first in terms of retries (which is what hours instead of minutes really is), next in refusing to continue reading after too many retries, and finally in disconnecting from the interface. Freezing the computer is just the opposite side of the coin. None of these behaviours are quirks. They represent a disk failing under normal use and each subsequent copy of that data will spend what remains of its life-span in attempts to access the areas of the disk where the problem lies.
What the bench did with it.
The order of the job →| Equipment used | Its work on this job | The reason for it |
|---|---|---|
| ACE Lab PC-3000 Express | Defect tables and read behaviour extracted from the firmware, where none of this shows in an ordinary read-out. | This allows access to the manufacturer's service area (where normal ATA commands cannot go) |
| DeepSpar Disk Imager 4 | Images created with retry limits set low; three quarters that were not saved taken first. | Mapped the heads first, then imaged one face of a platter per pass, with every reset, timeout and the power itself kept under our own control |
| R-Studio Technician | File system rebuilt off the image; what came out was opened one file at a time. | Constructs an array from the images, and reads nearly every file system |
What the bench did with it.
Copying was the wrong tool
Pulling files off manually had got him a quarter of the way through, and would get him no further. Each and every failed copy that gives up part-way asks the same weak ground for the same sectors over and over again, on a disk with only a limited number of reads left to be had. The order was turned around here: profile the drive, then make images from the drive, and leave until last any material that already has a second copy. Nothing was asked of the drive twice that did not need to be asked twice.
The unsaved three quarters went first
Reading steadily in one direction treats mechanisms better than fetching files to order, and it leaves difficult areas for a final pass. When that comes round, everything else is already on the copy, which was captured while the drive was still willing to cooperate. What he had saved himself was put off till the very end, since a second copy costs nothing but time.
A file list is not proof of a file
Directory listings do little more than give names, and say very little about what sits beneath them, so the image was worked through item by item and the files opened instead of counted. Each address that refused was followed back through the file table afterwards, so the report can name anything affected rather than quote a percentage. Results were compared against the quarter he already had before anything was sent home.
What went home.
The three quarters he did not manage to save were read off the image, checked item by item, and sent home alongside the quarter he already had. The Seagate stayed here. It had been describing its own condition for some time, first by slowing down and then by disconnecting, and the only thing anybody could have done differently was stop copying earlier.
Begin here if yours is doing the same thing.
More PC and laptop jobs off the bench.
Yours doing something similar? Power it down first.
Published prices are fixed. Memory cards and USB sticks are £250 + VAT. Any stand-alone drive is £300 + VAT. Drive configurations containing multiple disks (RAID, NAS or server) start at £500 + VAT. First assessments are always complimentary. Thereafter, data recovery charges are also fixed in advance and in writing, so you'll always know how much you owe before paying any money. Shut it down, get a quote first (by phone or with the form), then send it in or drop it off at our Guildford intake laboratory, Monday to Friday, 9am to 5:30pm (no appointment needed). On most jobs you only pay if we recover your data.