If you lost your PS2 format disc, you should give Sony a call and have them send you a replacment, or take a look on eBay, where someone might be selling an extra one for a heavily reduced price. You may be able to burn your own as well. Good Luck.
The PlayStation 2's "format disk" is basically a laser lens cleaner. You should be able to pick up a generic version of these at any electronics retailer.
I think that the best thing to do if you lose your playstation 2 format disk is to obtain a new one. I suggest checking your playstation manual for a customer service phone number to ask for a replacement disk.
If you have a PS2, you know that each game disk is formatted for use on the PS2, If you have a copy of the Game Disk, it will not play unless you do something Illegal to make it think the format disk is there.
The ps2 format disc ie., Playstation 2 format disc is one which helps us play games. If this ps2 is lost then it is better to get the new one from eBay where you can get for reduced price or you can move to sony for replacement.Else you can get a copy and burn by yourself.