Abusing CD-Rs, DVD-Rs, and BD-Rs for Science

I’ve been on an optical media kick lately, having a grand old time burning discs and whatnot. One bit of advice that consistently comes up: don’t let your burned discs get exposed to sunlight; the dye layer is UV after all, and since the sun is a deadly laser it can damage your precious bits.

Naturally, this advice needs to be tested to determine what actually happens if you disregard it.

I had a friendly LLM shart out some scripts to generate max-size iso images and sha256sum them from the disc, and burned using k3b:

• Verbatim CD-R (at max speed, 40x)
• Verbatim CD-RW (at max speed, 40x)
• Verbatim DVD-R (at max speed, 16x)
  • I also have a second DVD-R that long story short had 615 buffer underruns while burning. It passed verification, but it seemed like a poor test subject. I exposed it though because it would be interesting if using Burnfree made it degrade faster
• Verbatim BD-R (at max speed, 12x)

The CD and DVD were burned with a brand new (old stock) Hitachi-LG data storage GHD0N, the Blu-ray with a brand new LG WH16NS60. The blanks were also just purchased from Amazon, so hopefully they are fresh.

I verified each burn with k3b as well as my slop-script, and placed them in a ziplock baggie (so they don’t get physically dirty and ruin by readers) with the media side facing west in a window. They’ll get blasted by the sun for hours each day, and are physically warm to the touch.

I’ll update this post as I go along.

Updates

2026-09-06

Hung the discs in the window.

2026-09-21

Finally had time to check on these. Looks like I waited too long.

• CD-R: Read fine
• CD-RW: Read fine
• DVD-R: I could tell these were toast before I even put them in the drive. Visibly discolored ring around the middle, and an odd intrusion on the side of one as well. No longer have a blue tint.
• BD-R: Didn’t seem visibly damaged and my drive still recognizes it. The sector analysis software was able to get at least one good sector off of it after retying a few times, but it seems like this disc is toast too. Scan tool output</summary>

  Comparing 12219392 sectors from /dev/sr2 against /optical-stress-bd-r.iso
  Scan plan: start LBA=0, forward with wrap, chunk=256 sectors (524288 bytes), slow-read warning=5s
  Loading first source chunk: LBA=0-255 offset=0 bytes=524288
  Reading first device chunk: LBA=0-255 offset=0 bytes=524288
  
  Slow device read: phase=chunk LBA=0-255 offset=0 bytes=524288 elapsed=5s; optical drive or kernel may be retrying
  
  Slow device read: phase=chunk LBA=0-255 offset=0 bytes=524288 elapsed=10s; optical drive or kernel may be retrying
  device read returned: phase=chunk LBA=0-255 read=0/524288 elapsed=10.3s error=read /dev/sr2: input/output error
  Chunk read failed: LBA=0-255 read=0/524288 elapsed=10.3s error=read /dev/sr2: input/output error; bisecting range
  
  Slow device read: phase=recovery LBA=0-127 offset=0 bytes=262144 elapsed=5s; optical drive or kernel may be retrying
  
  Slow device read: phase=recovery LBA=0-127 offset=0 bytes=262144 elapsed=10s; optical drive or kernel may be retrying
  device read returned: phase=recovery LBA=0-127 read=262144/262144 elapsed=10.7s error=
  Compared 256 / 12219392 sectors (0.0%); last LBA 0-255; good=256 bad=0; 0.02 MiB/s; elapsed=26s ETA=342h31m10s    Chunk read failed: LBA=512-767 read=65536/524288 elapsed=4.8s error=read /dev/sr2: input/output error; bisecting range
  Unreadable sector: LBA=544 read=0/2048 elapsed=1.5s error=read /dev/sr2: input/output error (unreadable count=1)
  Unreadable sector: LBA=545 read=0/2048 elapsed=1.9s error=read /dev/sr2: input/output error (unreadable count=2)
  Unreadable sector: LBA=546 read=0/2048 elapsed=1.7s error=read /dev/sr2: input/output error (unreadable count=3)
  Unreadable sector: LBA=547 read=0/2048 elapsed=1.8s error=read /dev/sr2: input/output error (unreadable count=4)
  Unreadable sector: LBA=548 read=0/2048 elapsed=1.7s error=read /dev/sr2: input/output error (unreadable count=5)
  Unreadable sector: LBA=549 read=0/2048 elapsed=1.6s error=read /dev/sr2: input/output error (unreadable count=6)
  Unreadable sector: LBA=550 read=0/2048 elapsed=1.6s error=read /dev/sr2: input/output error (unreadable count=7)
  Unreadable sector: LBA=551 read=0/2048 elapsed=1.4s error=read /dev/sr2: input/output error (unreadable count=8)
  Unreadable sector: LBA=552 read=0/2048 elapsed=1.2s error=read /dev/sr2: input/output error (unreadable count=9)
  Unreadable sector: LBA=553 read=0/2048 elapsed=1.7s error=read /dev/sr2: input/output error (unreadable count=10)
  Compared 768 / 12219392 sectors (0.0%); last LBA 512-767; good=692 bad=76; 0.00 MiB/s; elapsed=5m56s ETA=1574h43m27s    Chunk read failed: LBA=768-1023 read=0/524288 elapsed=2.8s error=read /dev/sr2: input/output error; bisecting range
  Compared 1024 / 12219392 sectors (0.0%); last LBA 768-1023; good=930 bad=94; 0.00 MiB/s; elapsed=7m20s ETA=1458h25m20s    
  Slow device read: phase=chunk LBA=3072-3327 offset=6291456 bytes=524288 elapsed=5s; optical drive or kernel may be retrying
  device read returned: phase=chunk LBA=3072-3327 read=65536/524288 elapsed=6.4s error=read /dev/sr2: input/output error
  Chunk read failed: LBA=3072-3327 read=65536/524288 elapsed=6.4s error=read /dev/sr2: input/output error; bisecting range
  Unreadable sector: LBA=3109 read=0/2048 elapsed=2.4s error=read /dev/sr2: input/output error (unreadable count=100)
  
  Slow device read: phase=recovery LBA=3200-3263 offset=6553600 bytes=131072 elapsed=5s; optical drive or kernel may be retrying
  device read returned: phase=recovery LBA=3200-3263 read=65536/131072 elapsed=5.8s error=read /dev/sr2: input/output error
  ^Cmake: *** [Makefile:86: map-bd-r] Interrupt
  

  </details>

I’ll hang them back up and check in again later.