CPT 304: Operating Systems Theory and Design

  The goals of protection in an operating system are:           To prevent malicious misuse of the system by users or programs           To ensure each shared resource is used only in accordance with system policies           To ensure errant programs cause the minimal amount of damage To maximize security, programs, users and systems should be given just enough privileges to perform their tasks. This helps ensure failures will result in the least amount of harm done. An access matrix is a model of protection in which columns represent different system resources and rows represent protection domains. Cells within the matrix indicate what access that domain has to that resource. References Silberschatz, A., Galvin, P. B., & Gagne, G. (2014). Operating system concepts essentials (2nd ed.). Retrieved from  https://redshelf.com/

  The file management system is software used to determine how files are organized and stored. It allows users to browse, move, and sort files according to different criteria such as date of modification, date of creation, file type, etc. In Microsoft Windows, the file management system is Windows Explorer. On a Mac, the system is called Finder. Input devices allow a user to input data into a computer via a keyboard, mouse, touchpad, etc. while output devices provide the final product, such as a computer monitor, printer, or projector. These are all examples of hardware I/O devices because they are the components the user physically interacts with. The kernel's I/O subsystem provides numerous services, such as "I/O scheduling, buffering, caching, spooling, device reservation, and error handling" (Silberschatz et al., 2014). References Silberschatz, A., Galvin, P. B., & Gagne, G. (2014). Operating system concepts essentials (2nd ed.). Retrieved from  https://redsh...

  In the memory management diagram, the base and limit registers are used to provide the range of legal addresses the process may access (Silberschatz et al. 2014). The hardware address protection diagram shows how addresses are compared with registers, with a trap to capture any programs attempting to access the operating system in user mode. The multistep processing diagram displays steps a user program may go through before being executed (Silberschatz et al. 2014). Dynamic relocation diagram shows how “the value in the relocation register is added to every address generated by a user process at the time the address is sent to memory” (Silberschatz et al. 2014). Virtual memory can provide many benefits to the system and user by providing larger address space, allowing more programs to be run at the same time, and using less I/O to load or swap user programs into memory (Silberschatz et al. 2014). References Silberschatz, A., Galvin, P. B., & Gagne, G. (2014).  Operating...

  A critical section is the part of the process where the code for accessing the shared resources is written. The critical section problem refers to a solution which allows the processes to cooperate when they share common resources. In order for this to happen, a process must take care of three properties: mutual exclusion, progress, and bounded wait.          Mutual Exclusion: Only one process can execute its critical section at a time.           Progress: If a process doesn’t want to enter in its critical section, it should not be permitted to block another process from entering           Bounded Waiting: Bounded time up to which the process has to wait to enter its critical section after making the request. Ensures every process requesting to enter its critical section get the chance within the finite amount of time.   A software-based solution to critical section problem discussed in our te...

  A computer system consists of hardware, operating system, applications, and users. An operating system is software that manages computer hardware, acting as an interface between a user and the hardware. An operating system is responsible for allocating resources and services, such as memory, devices, processors, and information (Geeksforgeeks, 2021). The functions of an operating system include security, control over system performance, job accounting, error detecting, coordination between software and users, memory management, processor management, device management, and file management. Security management is responsible for controlling the access of programs, processes, or users to the resources defined by computer controls to be imposed, together with some means of enforcement. Process management creates, deletes, suspends, resumes, synchronizes and establishes communication between processes. File management creates, deletes and manipulates files and directories. File manag...