I am experiencing problems reading a disk volume (logical disk). Please note that I can open the volume just fine in HxD, with admin elevation. The volume is also working as expected in Explorer. I can read and write files to it in Explorer just fine. No other program is actively using it when I open it in HxD. None that I know of anyway, or that I have started myself.
The main problem is the very low reading speed. Which I think results in the device I/O error I see later on.
The volume is 646 GiB and I am using the Find function in HxD to search for a magic number. I manually note down the offsets for each match. But the low reading speed is a big problem for me. Not only because it will take many days to scan the entire volume, but also because HxD sometimes runs into an irrecoverable device I/O error. This means that I can't continue where I left off, but have to start all over again.
When I check the disk activity in Task Manager while HxD is doing the Find operation I can see it's 100% active and the read speed shifts from about 250 KB/s to 2.5 KB/s. At best, it reaches 7 or 8 MB/s. It sometimes jumps to about 20 MB/s and that's about it. It never goes above that.The request could not be performed because of an I/O device error.
It's very frustrating, as I'm sure you can understand. But there is more to it. It's a cascading problem where one problem leads to another, as often is the case with computers. I must use a disk editor in order to recover some very important data. I have no other option. And I must recover that data, and I know it can be done because I have already recovered some of it. But I need to recover more, on higher byte addresses. But for that I need a tool that works properly.
I have tested the commercial Hex Editor Neo, the full version, in trial mode. I have discovered one bug in it, several oddities, and it too had reading problems. I actually started out with Neo, before I tested HxD. Or I tested HxD first, found the estimated time remaining and the progress bar too discouraging and moved on to Neo in hopes that it would be faster. I thought that 646 GiB was just asking too much of such a program. I have used both HxD and Neo in the past, and I know they're both good but I never tried working with 646 GiB. So I didn't really know what to expect.
But I ran HxD yesterday, after several hours of frustration with Neo, and that time it reached an average of about 120 MB/s. I ran it for about 2 hours and reached the end of the disk volume. I found several matches. But I didn't start from the beginning. So I have missed some byte addresses. However, I am unable to reach the same read speed today. I don't know what was different with that session.
Any idea why I have this read problem? Could it be Windows 10 specific?
I am running HxD version 126.96.36.199 on Windows 10 Pro x64 (version 1511, build 10586.104). The physical disk is a WD Caviar Red, SATA3 in SATA2 mode. The PC has 8 GB of RAM and the CPU is overclocked at 2.9 GHz. It's a tower PC I built myself.