Operating Systems in a nutshell
Operating systems are the software that makes the hardware usable.
Operating systems perform the following rudimentary functions -
Process Management
Process Scheduling
Process Synchronization
Memory Management
In addition, an operating system(OS) also provides facilities like a GUI or embedded application software that make the system more user-friendly.
OSs generally deal with allocation, scheduling and monitoring of resources available to the system. Popular examples are the Windows, Linux and Mac OS series.
A process is a program in execution. Processes require resources to complete execution and the allocation of these resources is fulfilled by the operating system. Appropriate allocation algorithms must be utilized to avoid deadlocks. A deadlock occurs when the system is in a standstill because the requirements of all processes can't be met due to a lack of available resources. Common examples of deadlock are the dining philosophers problem and the readers/writers problem.
An address generated by the CPU is commonly referred to as a logical address, whereas an address seen by the memory unit—that is, the one loaded into the memory-address register of the memory—is commonly referred to as a physical address. Dynamic loading involves loading the process into the main memory whenever it is to be executed and storing it in a secondary storage device otherwise. There are many memory management models like paging, segmentation, contiguous memory allocation and others, all of which have their own merits and disadvantages. The virtual memory concept allows large programs whose sizes exceed the main memory's size to be executed in portions. Virtual memory generally involves fixed-size chunks of data called pages. These pages are loaded into the main memory from a secondary storage device using appropriate algorithms. A page fault occurs when a required page is not found in the main memory, in which case the page address is loaded into the page table and moved from the secondary storage device to the main memory. A process is said to be thrashing when it spends more time paging than executing.
Operating systems also handle files, which are a collection of data. Every file has a name and a type. Files are used to organize data into meaningful blocks. Directories or Folders may be implemented in several ways. Two general implementations are the linear list and hash table methods. Three major methods of allocating disk space are in wide use: contiguous, linked, and indexed.
Operating systems perform the following rudimentary functions -
Process Management
Process Scheduling
Process Synchronization
Memory Management
In addition, an operating system(OS) also provides facilities like a GUI or embedded application software that make the system more user-friendly.
OSs generally deal with allocation, scheduling and monitoring of resources available to the system. Popular examples are the Windows, Linux and Mac OS series.
A process is a program in execution. Processes require resources to complete execution and the allocation of these resources is fulfilled by the operating system. Appropriate allocation algorithms must be utilized to avoid deadlocks. A deadlock occurs when the system is in a standstill because the requirements of all processes can't be met due to a lack of available resources. Common examples of deadlock are the dining philosophers problem and the readers/writers problem.
An address generated by the CPU is commonly referred to as a logical address, whereas an address seen by the memory unit—that is, the one loaded into the memory-address register of the memory—is commonly referred to as a physical address. Dynamic loading involves loading the process into the main memory whenever it is to be executed and storing it in a secondary storage device otherwise. There are many memory management models like paging, segmentation, contiguous memory allocation and others, all of which have their own merits and disadvantages. The virtual memory concept allows large programs whose sizes exceed the main memory's size to be executed in portions. Virtual memory generally involves fixed-size chunks of data called pages. These pages are loaded into the main memory from a secondary storage device using appropriate algorithms. A page fault occurs when a required page is not found in the main memory, in which case the page address is loaded into the page table and moved from the secondary storage device to the main memory. A process is said to be thrashing when it spends more time paging than executing.
Operating systems also handle files, which are a collection of data. Every file has a name and a type. Files are used to organize data into meaningful blocks. Directories or Folders may be implemented in several ways. Two general implementations are the linear list and hash table methods. Three major methods of allocating disk space are in wide use: contiguous, linked, and indexed.
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