Definition 1: In order to perform two functions: management support software application, call the allocation of resources on the hardware level, under the application
2.kernel kernel: the focus of the operating system, includes four parts:
the CPU
memory
files
interrupt handling and peripherals driving
3.kernel wherein:
concurrent: there is a period of time more programs running
(parallel: a plurality of programs at one point in time, a plurality of CPU)
sharing: sharing, while a mutually exclusive resource sharing only one program access to
virtual: the operating system are faced with the hardware, the CPU virtualization process, into a virtual disk file, virtual memory into space, each application that has a computer dedicated service
asynchronous: in the case of a CPU, only one program running, running is not always in the end, but stop and go
4 interrupt and abnormal system call
interrupts: peripheral sent a request timer from different hardware devices and network outages
exception: bad illegal instruction application processing state and a bad
system call: an application actively sends a request to the OS system call service
Differences: 1 source different sound cards and other card generates an interrupt event, APP unexpected behavior is abnormal, APP active service call request OS system
2. Processing time: interrupts: asynchronous exception: synchronization system call: synchronous or asynchronous
asynchronous meaning: that when an event occurs, APP does not know when it happens
it is of course interrupted asynchronous exceptions and system calls is a specific instruction triggered the event, time synchronization point
3. interrupt response status: continuous, APP user is transparent, feel
abnormalities: abnormal APP killed or re-execute the instruction, but also transparent
system calls: wait and continue
