Protection, Security and Kernel Data Structures

7- Protection and Security

Protection is any mechanism for controlling the access of processes or users to the resources defined by the computer system. Protection and security require the system to be able to distinguish among all its users. Most operating systems maintain a list of usernames and associated user identifier. In Windows users are also identified by security ID (SID). When any user request to access any service/data by the operating system, OS first identify the authorization access of user and then continue accordingly. System generally first distinguished among users, to determine who can do what

User identities (User ID and security ID) include name and associated number, one per user
User ID then associated with all files, processes of that user to determine access control
Group identifiers (Group ID) allow set of users to be defined and control managed, then all associated with each process, file
Administrator user (superuser) allow to define rules for other users, how to access control to the system

8- Kernel Data Structure

Now I will tell you shortly, the way data are structured in the operating system. Operating system usually use Lists, Stacks, Queues, Trees, Hash structures and Maps data structures to store data. All the discussion about these data structures will discuss later.

Hasnain Jamil