Re: Burning and mounting written BDs

[Kjetil Kjernsmo]

Hi!

Thanks a lot for the detailed replies!

On torsdag 28. desember 2023 16:06:35 CET Thomas Schmitt wrote:
> > xorriso : UPDATE :   40115 nodes read in 9 seconds
> 
> This means it should be mountable (after due waiting for the drive to
> settle after loading the tray).

OK, that's good!

> Eventually errors occur:
> > xorriso : UPDATE :  14648k blocks read in 1136 seconds , 1.1xB
> > libburn : SORRY : SCSI error on read_10(15000832,32): [4 3E 02] Drive
> > error. Timeout on logical unit. xorriso : UPDATE :  14649k blocks read in
> > 1146 seconds , 0.1xB
> 
> I am undecided whether it is the drive firmware or the kernel driver
> which emits this error code [4 3E 02]. Whatever, the drive has problems
> with the medium.

Alright, OK! I have previously used this successfully even with 100 GB M-Disc, 
and I recently bought a spindle of 50 GBs. I had also one 25 GB M-disc left.
 
> A few more blocks can be read but the error comes back several times:
> > libburn : SORRY : SCSI error on read_10(15001696,32): [4 3E 02] Drive
> > error. Timeout on logical unit. libburn : SORRY : SCSI error on
> > read_10(15002720,32): [4 3E 02] Drive error. Timeout on logical unit.
> Then comes an error which clearly stems from the drive firmware:
> > libburn : SORRY : SCSI error on read_10(15004480,32): [3 11 05] Medium
> > error. L-EC uncorrectable error.
> After many of these, the run gets aborted due to a safety limit which
> i installed in xorriso:

Ouch, yes, that's what I feared...


> > xorriso : NOTE : -check_media: Reached time_limit=28800
> > xorriso : UPDATE :  14859k blocks read in 28801 seconds = 0.2xB
> 
> 8 hours is more than i expected as human patience from Kjetil.

Hehe, I started it and went to bed :-) 

> I hope the drive is still well.
> 
> In the beginning of the problems, the unreadable regions were only 64 or
> 128 KiB of size. But about 120 MB further on, the unreadable regions grow
> to about 400 KiB. The unreadable sizes grow to several MB after 200 MB
> more of slow and bumpy reading.


Yeah.

> -----------------------------------------------------------------------
> Summary:
> 
> Even if the medium is probably mountable, about 30 percent of the data
> file content is in the range that causes errors or is in the yet untested
> range at the end of the medium.

Yeah, and that's not suitable for the purpose indeed.

> You may learn the names of the data files in the problem area by:

I just discarded that one....

> -------------------------------------------------------------------------
> Proposals for burning a new annual backup without wasting too much money:
> 
> - Use single layer 25 GB M-disc BD-R and split your backup into two.
>   (That's how my project scdbackup began in 1998 when i had to split
>    my periodic backups over more than one CD-RW media.)

OK, I had a single 25 GB M-disc left, so I just started writing to that, 
fingers crossed! I have about 119 GB of data in total, so it'll take a few 
discs.

[snip stuff for future reference, thanks a lot]

> I myself would use "25 GB" non-M-disk BD-R media and invest the saved
> money into multiple copies. I would probably make one copy on BD-RE
> just to have a wider range of chemical media properties.

OK, I can try that.

> After all, chances are good that a normal BD-R stays readable for decades
> if its initial read quality is sufficient.

Yup!


> Have a nice day :)

Thanks a lot, and thanks the same! I'll keep you posted on the current write 
I'm doing!

Kind regards,

Kjetil