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EDIT3: In response to requests to see the output of dmesg, there appear to be a few errors like the following:

[ 7102.039819] perf: interrupt took too long (2502 > 2500), lowering kernel.perf_event_max_sample_rate to 79750 [ 8278.017874] sr 4:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [ 8278.017876] sr 4:0:0:0: [sr0] tag#0 Sense Key : Blank Check [current] [ 8278.017877] sr 4:0:0:0: [sr0] tag#0 Add. Sense: No additional sense information [ 8278.017878] sr 4:0:0:0: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 00 00 00 01 00 [ 8278.017879] blk_update_request: critical target error, dev sr0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0 [ 8278.019391] sr 4:0:0:0: [sr0] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [ 8278.019392] sr 4:0:0:0: [sr0] tag#0 Sense Key : Blank Check [current] [ 8278.019392] sr 4:0:0:0: [sr0] tag#0 Add. Sense: No additional sense information [ 8278.019393] sr 4:0:0:0: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 00 00 00 01 00 [ 8278.019394] blk_update_request: critical target error, dev sr0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0 [ 8278.019396] Buffer I/O error on dev sr0, logical block 0, async page read 

I think this is to do with my USB Blu Ray drive, though someone may be able to correct me.

Perhaps I'm doing something very stupid here, but Google hasn't been very helpful in resolving the problem.

I have an archive of files I made for backup purposes. I've generated an SHA1 checksum file from this archive:

sha1um myarchive.tar > myarchive.tar.sha1 

The contents of this file are as follows:

6f5d7bdd71fe25ed8e881265fdb8a8bbcdaa41c1 myarchive.tar 

I have also run the SHA1 process in the terminal without piping to a file:

sha1sum myarchive.tar 

This gives me the output:

6f5d7bdd71fe25ed8e881265fdb8a8bbcdaa41c1 myarchive.tar 

Clearly these checksums are the same. However, when I run the verification command, with the archive and its SHA1 file next to each other in the same directory:

sha1sum -c myarchive.tar.sha1 

I get an error message saying that the checksum does not match:

myarchive.tar: FAILED sha1sum: WARNING: 1 computed checksum did NOT match 

Obviously something is wrong here, but I have no idea what it could be. Can anyone enlighten me?

EDIT: Interestingly, doing two consecutive MD5s on the file comes up with two different checksums. Now I'm very confused.

$ md5sum myarchive.tar 9a15036eed341613bbcf2c4b53a09859 myarchive.tar $ md5sum myarchive.tar a662d6b469627c62f2b03ee0df067436 myarchive.tar 

EDIT2: Additional context:

• This is on real hardware (my Ubuntu MATE 19.10 desktop machine).
• The archive I've made was destined for a Blu Ray backup disc. It's 22.6GB in size.
• Performing an SHA1 verification of the file as burned to the Blu Ray disc ends up being successful.

Perhaps I'm doing something very stupid here, but Google hasn't been very helpful in resolving the problem.

I have an archive of files I made for backup purposes. I've generated an SHA1 checksum file from this archive:

sha1sum myarchive.tar > myarchive.tar.sha1 

The contents of this file are as follows:

6f5d7bdd71fe25ed8e881265fdb8a8bbcdaa41c1 myarchive.tar 

I have also run the SHA1 process in the terminal without piping to a file:

sha1sum myarchive.tar 

This gives me the output:

6f5d7bdd71fe25ed8e881265fdb8a8bbcdaa41c1 myarchive.tar 

Clearly these checksums are the same. However, when I run the verification command, with the archive and its SHA1 file next to each other in the same directory:

sha1sum -c myarchive.tar.sha1 

I get an error message saying that the checksum does not match:

myarchive.tar: FAILED sha1sum: WARNING: 1 computed checksum did NOT match 

Obviously something is wrong here, but I have no idea what it could be. Can anyone enlighten me?

EDIT: Interestingly, doing two consecutive MD5s on the file comes up with two different checksums. Now I'm very confused.

$ md5sum myarchive.tar 9a15036eed341613bbcf2c4b53a09859 myarchive.tar $ md5sum myarchive.tar a662d6b469627c62f2b03ee0df067436 myarchive.tar 

EDIT2: Additional context:

• This is on real hardware (my Ubuntu MATE 19.10 desktop machine).
• The archive I've made was destined for a Blu Ray backup disc. It's 22.6GB in size.
• Performing an SHA1 verification of the file as burned to the Blu Ray disc ends up being successful.