There are many times Linux OS hangs, shows unusual behaviour like X server rebooting again and again, some application crashed. These situations are referred to as kernel panic in Linux.
Kernel Panic in Linux occurs when our system/or any application refers to some memory location which doesn't exist or its reference is invalid.
There are two main types of kernel panics:
1) Hard Panic (equivalent to Aieee! ), which mostly occurs due to driver crash, storage/network failure2) Soft Panic (equivalent to Oops),which mostly occur whenever any application fails, or any service failed which doesn't impact the overall system and our system is still in responding state.
Let us take an example of Hard panic.
Suppose our system is running fine, and unexpectedly there is some storage/network failure which is connected to system, and our system which is regularly interacting with the storage filer/network, now not able to do so. In such cases many of the times Linux system mount point hangs or its root filesystem / go into read only mode, which is a hard panic of the system becasue this issue can't be corrected until the system reboot or filesystem check.
Hard Panic can be compared to the Blue screen in Windows.Soft Panic can be compared to some application fail like you ran your favorite game nfs and it failed to start which don;t have any impact on system functionality.
Now i believe after reading this post, you now have a good idea of what is kernel panic and what is the difference between hard/soft panic.
