I did
fdisk -l
and found that I have 15 different ramdisks which are all called
/dev/ram* (where * is a number between 1 and 15.)
This seems weird, but I'm not a hardware specialist so I don't really know if they are all needed or if I should just change/delete some of them. So, is this normal and should I leave it alone, or should I change something here?
As you've already discovered, these devices are something called "ramdisks," which are essentially a system put in place in case you ever want to use them. They're perfectly normal on any Linux system and require no alteration.
In fact, you can't even delete them. Anything in /dev isn't really "on" your hard drive. They're only abstract representations of devices that are injected into your filesystem for convenience. Deleting something from /dev will (at best) do absolutely nothing or (at worst) break your entire computer.
Any entries in /dev are assigned and managed by the kernel (more accurately, udev), and take up no space on your hard drive at all, as it's a tmpfs partition:
udev on /dev type devtmpfs (rw,relatime,size=498080k,nr_inodes=124520,mode=755)
