The modern OS is a complex structure comprised of millions of lines of code. Not all information is released, and is this core components, or everything including additional apps that have been included?

Mac OS X Tiger (10.4) ~ 84 Million Lines of Code

Windows Vista (2009) ~50 Million Lines of Code

Debian 7.0 (2012) ~419 Million Lines of Code

The kernel of an OS is the minimal set of functions necessary to manage the system resources safely and efficiently. The kernel provides the most essential of services for the OS.

The CPU is divided into two sets: privileged and non-privileged. A privileged instruction performs critical operations. Only the OS kernel is allowed to execute privileged instructions.

A system call is a request from an application for an OS service. 

The OS structure was originally found on Access 2 Learn

Assistant Professor

Walter Wimberly is an Assistant Professor at a regional college in Tennessee, teaching Computer Science in the Software Engineering track. He works as a student advisor, oversees curriculum changes, develops new courses, and manages the advisory panel.
Walter taught full time for about 7 years, before going back into “industry” as a full stack Software Developer for a dozen years. There he focused on web based projects coding in JavaScript/jQuery and utilizing the Bootstrap CSS Framework on the front-end, and coding in PHP, ASP/ASP.Net, SQL on the back-end.

Since he loves teaching, he taught as an adjunct web and digital media classes for eight (8) years, while working in industry, and has since returned to teaching full time.

He has been married for over 25 years, and is father to several special needs boys. As such, he is working on some projects to help others who have special needs to be self-sufficient, and support the care givers of those with special needs. Check out his Autism blog for more info.

Similar Posts

Role of the OS

ByWalter Wimberly

Book chapter notes: The operating system (OS) is the software that runs on the bare hardware of a computer and provides essential support for users to develop and use applications in the most efficient and safe manner. The OS will also serve as an abstraction layer for the user/applications to interact with hardware. The OS can serve…

Monitors

ByWalter Wimberly

P and V operations on general semaphores are versatile primitives capable of solving a variety of synchronization problems. But they are low-level primitives, prone to difficult-to-diagnose programming errors. (see the issues that we need to avoid in Process Interactions – those are some of the errors you might run into.) A monitor is a high-level synchronization primitive…

Disk Block Allocation

ByWalter Wimberly

The file system sees a file as a series of blocks where the file physically exists on the disk. That disk block can only be accessed as a single unit using low-level read-block and write-block operations.  In a contiguous block allocation scheme, every file is mapped into a contiguous sequence of disk blocks. The FCB points to the…

A System Model for Deadlocks

ByWalter Wimberly

A resource allocation graph shows the current allocation of resources to processes and the current requests by processes for new resources. Processes are represented by circles. Resources are represented by rectangles. Small circles designate multiple units within a resource. Resource allocations are represented by edges directed from a resource to a process. Resource requests are represented by…

Combined Approaches

ByWalter Wimberly

If you work with a system that only has batch processes, or only does real time applications, then your scheduling algorithm selection is much easier. You pick an appropriate choice and go with it… However, the modern desktop OS will often include a combination of batch, interactive, and real-time applications. Therefore picking “a” solution isn’t…