Umm, if your talking about weight they weigh the same. Memory is stored digitally and does not add any weight.
No you can't. The main supplied disk is fully loaded to the hard drive for use.
The system disk is the partition from which the operating system was loaded at startup.
You cannot BUY it on a disk but you can put it on an empty disk after you download it.
command + R
Most people just place the disk to hear it but you can download it like any music disk.
No- it is loaded onto your "Steam" account so you can play whenever, whithout a disk.
If you do not have a recovery disk and your computer crashes and you lose everything, which I hope doesn't happen, but without a recovery disk, your computer will be worthless and it will have nothing to work on. It will be empty.
The drivers to access it as a disk are loaded.
The memory must be available, so no operating system can be loaded. Though technically there is no reason why you cant run it from a hard disk.
The data is still there. When you format a disk you're just telling the hard disk controller that the disk is effectively empty and it's okay to overwrite any data that may be on it. This is why "undelete" programs work.
We will have a TOTAL solar eclipse!
Programs are normally stored on a hard drive and loaded into memory for execution.