Some ceramics heat up in the microwave. You have experienced this probably, whenever the bowl is searing hot but the food cold. That’s when a thing is not microwave safe.

When it’s microwave safe it won’t absorb the waves and won’t heat up.

I think semicolon separated files should be named SSV

Hard disks may fragment when one tries to compact them. It will need to be defragmented afterwards.

Softer disks are more amenable to be compressed into compact disks, floppy ones work best.