What are the main parts of Solaris OS ?

1. Kernel

• Core of the OS
• Main tasks : 
• Manage devices - Memory, processes and deamons
• Manage system resources
• Task scheduling
• Schedule / executes all commands
• Memory management
• Interaction between physical resources and software

2. Shell

• An interface between user and kernel.
• It accepts commands, interpret them and sends executable to the Kernel
• Three types of shell :
• Bourne shell ($)
• /sbin/sh
• Default shell
• developed for Unix environment
• C shell (%)
• /bin/ksh
• Same syntax as C language
• Same features as Korn shell
• Korn shell ($)
• /bin/ksh
• Superset of Bourne shell
• Added features like Aliasing, history and Command line editing 

3. File structure

• Hierarchy of directories, sub-directories, and files organized or grouped for a specific purpose
• Top-most directory is root ( / )
• /usr : contains sub-directories :
• bin : for executable commands
• lib : for system libraries
• /opt : contains unbundled & 3rd party software applications
• /dev : contains logical device names for physical devices to access I/O devices (Disk/Tape/Keyboard/Monitor etc.)
• /etc : contains system admin files like, passwd and hosts files
• /export : contains user's home directory
• /kernel : contains kernel files