Every device in linux has device node under
/dev/ (The default).
Pattern is: Hard Disk type,Hard Disk Number,Partition Number
sd means SATA hard disk
hd means IDE hard disk
a means First hard disk ,
b Second and so on.
1 First partition,
2 Second and so on.
sda1 means First SATA hard disk and partition.
sdb1 means Second SATA hard disk and First partition
hda2 means First IDE hard disk and Second partition
/boot or / or /home are directories... When linux boots up it mount partitions under
/dev/ to specified directories. From your
df -h output
/dev/sda1 mounted on
/boot directory.. But why mount?! Because if you want to use hard disk you need to mount partition to a directory for access and use it.
tmpfs: Tmpfs is a file system which keeps all files in virtual memory.
For more details read following links: