Purpose Of The Pin Hole.
Lets say you have a CD or a DVD inside your CD/DVD ROM and your computer no longer turns on.
Your computer refuses to turn on, power button doesn't work. You start to think that the world has ended because your favorite movie or music CD is inside and without power the CD-ROM wont open.
Think again, the world has not ended quit yet. Look at your CD-ROM, notice that pin hole. You can open the CD-ROM or DVD-ROM by inserting something small enough to open it. No power no problem, that is why that pin hole is there in the first place. Just unfold a paperclip and stick it in there. lol
It opens up and you can now retrieve your disk.