Ok, so you have a little history and an idea what Linux is. But, what is the difference between Windows and Linux?
Windows got its start as a small operating system called DOS back in 1981. It was meant for a single user on a single computer to do word processing, spread sheets, games, etc.
Linux started off as Unix in 1970. Unix was a product of AT&T and Bell Labs, meant to run a large computer supporting multiple users. In 1991, Linus Torvalds rewrote Unix to fit on the smaller desktop computer, like the ones used for Windows. The major differences were that Windows was a single user platform, while Linux maintained the multi-user platform. And, it is FREE!
Since Windows assumed a single user environment, they developed a structure as follows:
A:, the floppy disk drive. This is where the operating system resides. You swap disks for your program and data.
B;, the second floppy disk drive because you got tired of swapping disks all the time.
C:, The major improvement when hard disk drives became available. Now the OS and programs are here, with data on A:.
D:, Another improvement when the CD disk was implemented
Now, it gets complicated! You can put a data partition on the hard drive. That becomes D:, making the CD E:
Then you add a second hard disk for more storage. It becomes E:, so the CD is now F:
Then you add network drives. They get mapped wherever unless IT specified something special.
So, you have to know where the program you want is, and where your data goes, and hope the drive letter didn't change!
Since Linux was derived from a multi user environment, there were miltiple drives, printers, terminals in use. So, Linux has no drive letters. There is one big directory structure. No C:\programs\norton.... or whatever. Everything stems from what is called root, and defined as / For example,
/bin is where some programs reside to do system functions
/boot is a collection of files used for booting
/dev is device files. Here are links to all disks, printers, keyboards, mice, terminals, etc. Everything in Linux is a file!
/home every user will have a subdirectiory here. All data for a user will be here in his subdirectiory. Save /home, you've got it all!
and the list goes on.... Geek Heaven!
Drives are automatically, seamlessly integrated into one big directory system. If you add a USB storage device, it will typically appear at /media/(Your user name)/(The device ID number) But you don't usually care. A file manager or photo program window will pop up and you don't need to know where they are. You simply copy, then paste to /home/(Your user name)/where you want it.... Now, if you are following somebody's project directions, or you are a Geek doing your own, you will edit a file called /etc/fstab. This file will mount your new media where ever you want it!
To get technical, typically your hard drives and USB devices will follow a certain format. The first device found will be sda. The next, sdb, Then sdc and so on. On each device, the first partition will be 1, the next 2, so the first and second partition of the first drive will be sda1 and sda2. So, the 2nd partition of the third drive is sdc2. Typically, they will be referenced as /dev/sda1 ,/dev/sdb2, etc. You will only need to know if you want to specify where a drive will appear. If you are following a project, it will tell you.
So, as a multi user, multi process system, you can be logged in directly to the pi doing word processing, logged in over your laptop transferring files to somewhere else, somebody else logged into your webcam over the net, and your smart tv streaming video. Linux doesn't care. It divides it's processing time among everybody to keep them all happy!
The next topic to cover is Permissions.txt
Jim Albrecht, K2BHM