Operating Systems
- — What is an OS?
- — A software providing platform for other softwares and handling low level hardware communications
- — It is compiled program that is loaded after startup
- — It can update registries and send and read messages from hardware bus
- — It passes control to user programs and gain back control using inxt instruction address
- — How it deals with hardware?
- — It discovers hardware by sending messages on the bus
- — Gets the ability to talk to any hardware with drivers
- — OS have standard interfaces on talking to categories of devices
- — Drivers tranlsate hardware instructions to fit these standard interfaces
- — Hardware OS needs like mouse, keyboard and monitory need to fit these
- — Specizlized hardware need not. Some someware can sent just raw messages
- — Components
- — Hardware interface
- — Processes management
- — Device management
- — File system
- — Network management
- — Graphical user interface
- — What are processes?
- — A compiled program in action
- — OS gives switch to this code and gain back control with interrupts
- — OS creates an information space in memory for a process that contain details
- — How GUI works?
- — GUI is another process communicating with other processes
- — GUI's memory space has what is displayed on screen (the windows and other widgets)
- — Processes sent messages to GUI to create window and add thigns to window
- — Lots of defaults and customizations there
- — GUI process gets inputs from keyboard, mouse, touchscreen etc.
- — Determines which process to pass the event to passes events
- — Proceess should have registered handlers with the OS for handling