Wrong disc size reported in Discover/Read

[Ken852]

Sometimes it just so happens that the reported disc size in Discovery or Read mode is off by a few thousand bytes, sometimes tens of thousands bytes or more.

For example, I recently had a Nero 7 Premium CD inserted to see if the drive would pick it up. At the time, ImgBurn reported 657,485,704 bytes in Discovery mode. A few days later and the same disc is now reported as  659,361,792 bytes. That's off by 1,876,088 byte or 1.78 MB.

For another disc, ImgBurn reported one size in Discovery mode (I don't recall the number), but after reading the disc to an ISO file and seeing that the ISO file was about 80000 bytes larger, I went back to Discovery mode and saw that the size reported was in fact about 80000 bytes smaller. But after refreshing (F5) it was quickly updated to report the same size as the ISO file is in.

In one example it was off by exactly 4096 bytes. If I recall correctly a single sector is 2048 for data discs, so two would be 4096 bytes. So it missed 2 sectors? The diff always appears to be a multiple of 2 or some multiple of 2 times 10.

Is this an indication that my old optical discs are diminishing before my eyes? Perhaps some areas of the discs are more difficult to read? Is it common that ImgBurn reports wrong size? I have not encounter any read errors with any of the discs I used for testing.

Edited March 18, 2021 by Ken852

[Ken852]

Now I find that a Verbatim DVD-RW containing Numb3rs Season 1 disc 3 is reported as 4,698,439,680 bytes in size. It was 4,697,804,800 bytes previously. That's a 634,880 bytes diff, presumably 310 sectors were missed on the first count?

 

  

[LIGHTNING UK!]

Discovery mode is for zero filling discs (burning all zeros to them) - used when running disc quality checks.

Don’t use it for anything beyond that.

The size reported by the program is what the drive reports. If it’s changing, either your drive is messed up or you’ve got some 3rd party software messing around with the response. The program isn’t actually ‘counting’ the sectors itself.

[Ken852]

Before I go any further, is there anything I can do to check if my drive is in a good healthy condition? Using ImgBurn or otherwise?

It's the Samsung SH-224DB model. I'm using it with Windows 10. I purchased it about 3 years ago, brand new, but I think it's a model from year 2013. I have not used it much, so I don't know how well or how badly it performs. One thing I notice is that it is not very fast when reading discs. According to specs it's supposed to be able to read CD at 40x speed (writing CD-R at 48x and CD-RW at 24x). It rarely reaches 12x or so. Not even when I specifically set the read speed to 40x (for data and audio tracks).

I reckon this might be more of a Windows problem than ImgBurn or drive problem. One major issue I'm having with File Explorer in Windows 10 is that it takes what seems like ages for that little program to figure out how to display drive icons whenever in the "This PC" view. See whenever I insert a disc, and open File Explorer, I get a green status bar at the top in the address/path moving slowly from left to right and all the drive icons either go blank or just some of them, mainly the one for the optical drive. It goes 1, 2, 3, 4, 5, 6, 7, 8... it can take a whopping 60 seconds before it returns an icon for whatever disc I have inserted, one with embedded icon of course, or even a generic icon like the one for Audio CD discs depicting a CD with a musical note. It's extremely painful to watch this unfold, and if I don't wait and just open to see the contents of the disc I get no results whatsoever, all I see is a blank File Explorer window and File Explorer is "thinking" again, before it displays all the files for me in full. In fact, Audio CD discs are usually the ones that load and refresh fastest, data CD and DVD discs are most problematic. And yet, at the same time, ImgBurn is somehow able to display disc information almost instantly.

Does anyone recognise this type of problem in File Explorer and Windows? It's not even specific to optical media and optical drives alone. This happens to me all the time even when I insert a USB flash drive, and sometimes when I don't insert any kind of media but just open up This PC. I'm told that it's due to some kind of caching that Windows or File Explorer does, but I have cleared the cache on more than one occasion and even walked the steps of the Windows troubleshooter (the "fix-it" type of scripts you can download from Microsoft website) for File Explorer specifically. None of which has helped. I now have it happen on two different Windows 10 computers.

Do you think this could cause these discrepancies in reported disc sizes?