CS & BCA Notes

Operating System Architecture    1.        MONOLITHIC SYSTEMS     The core software components of an operating system are collectively known as the kernel . The kernel has unrestricted access to all of the resources on the system.  In monolithic systems , each component of the operating system was contained within the kernel, could communicate directly with any other component, and had unrestricted system access. While  this made the  operating system very efficient, it also meant that errors were more difficult to isolate, and there was a high risk of damage due to erroneous or malicious code.  2.  L ayered OS architecture   The layered structure approach breaks up the operating system into different layers and retains much more control on the system.         The bottom layer (layer 0) is the hardware, and the topmost layer (layer N) is the user interface. These layers are so designed that each layer uses the functions of the lower-level layers only.   It simplifies the debugging

  Operating System Unit I Classification of Operating System  Batch Operating System MultiProgramming System Multiprocessor System D esktop Systems   · In Desktop Systems, Instead of maximizing the CPU and peripheral utilization, it is for maximizing user convenience and responsiveness.  · These systems are called Desktop Systems and include PCs running Microsoft Windows and the Apple Macintosh .  · Operating systems for these computers have benefited in several ways from the development of operating systems for mainframes .  · Microcomputers were immediately able to adopt some of the technology developed for larger operating systems.  · On the other hand, the hardware costs for microcomputers are sufficiently low that individuals have sole use of the computer, and CPU utilization is no longer a prime concern.  · Thus, some of the design decisions made in operating systems for mainframes may not be appropriate for smaller systems.  Distributed Operating System   The motivation behind d