Operating Systems Day 01

Figure below shows four subsystem managers supporting the User Command Interface.

Figure below shows the network operating system

Figure below shows the current design of operating systems.

Figure below shows a fix-head disk.

Figure below shows a movable-head disk.

Figure below shows a magnetic disk.

Figure below shows an optical disk.

The CPU (Central Processing Unit) executes instructions that operate on data in registers.

The cycle is Fetch-Decode-Execute.

Modern desktop computers clocks can tick in excess of 3 billion times per second.

File Manager: the section of the operating system responsible for controlling the use of files.

Kernel: the primary part of the operating system that remains in random access memory (RAM) and is charged with performing the system’s most essential tasks, such as managing main memory and disk access. It resides in memory at all times, performs essential tasks, and protected by hardware.

Operating system: the software that manages all the resources of a computer system.

Processor Manager: a composite of two submanagers, the Job Scheduler and the Process Scheduler, which decides how to allocate the CPU.

Software: a collection of programs used to perform certain tasks. Software falls into three main categories: operating system programs, compilers and assemblers, and application programs.

Thread: a portion of a program that can run independently of other portions. Multithreaded applications programs can have several threads running at one time with the same or different priorities.

Virtualization: the creation of a virtual version of hardware or software. Operating system virtualization allows a single CPU to run multiple operating system images at the same time.

References
McHoes, A., & Flynn, I.M. (2008). Understanding operating systems (5th ed.). CENGAGE Learning.