Symmetric Multiprocessor System
Symmetric multiprocessing (SMP) involves a multiprocessor computer hardware and software architecture where two or more identical processors are connected to a single, shared main memory, have full access to all input and output devices, and are controlled by a single operating system instance that treats all processors equally, reserving none for special purposes.
Most multiprocessor systems today use an SMP architecture.
In the case of multi-core processors, the SMP architecture applies to the cores, treating them as separate processors.
Asymmetric Multiprocessor System
An asymmetric multiprocessing (AMP or ASMP) system is a multiprocessor computer system where not all of the multiple interconnected central processing units (CPUs) are treated equally.
Other AMP systems might allow any CPU to execute operating system code and perform I/O operations, so that they were symmetric with regard to processor roles, but attached some or all peripherals to particular CPUs, so that they were asymmetric with respect to the peripheral attachment.
Multi-core Processor
A multi-core processor is a computer processor integrated circuit with two or more separate processing units, called cores, each of which reads and executes program instructions, as if the computer had several processors.
The instructions are ordinary CPU instructions (such as add, move data, and branch) but the single processor can run instructions on separate cores at the same time, increasing overall speed for programs that support multithreading or other parallel computing techniques.
Multithreading
Multithreading is the ability of a central processing unit (CPU) (or a single core in a multi-core processor) to provide multiple threads of execution concurrently, supported by the operating system.
This approach differs from multiprocessing.
In a multithreaded application, the threads share the resources of a single or multiple cores, which include the computing units, the CPU caches, and the translation lookaside buffer (TLB).
Hyperthreading
Hyper-threading is Intel’s proprietary simultaneous multithreading (SMT) implementation used to improve parallelization of computations (doing multiple tasks at once) performed on x86 microprocessors.
Hyper-Threading allows each core to do two things simultaneously.
It increases CPU performance by improving the processors efficiency, thereby allowing you to run multiple demanding apps at the same time or use heavily-threaded apps without the PC lagging.
Benefits of Multithreading in Operating System
The benefits of multi threaded programming can be broken down into four major categories:
Responsiveness, Resource Sharing, Economy, Scalability.
System Protection in Operating System
Protection refers to a mechanism which controls the access of programs, processes, or users to the resources defined by a computer system.
We can take protection as a helper to multi programming operating system, so that many users might safely share a common logical name space such as directory or files.
File System in Operating System
A file is collected of related information that is recorded on secondary storage.
Or file is a collection of logically related entities.
From users perspective a file is the smallest allotment of logical secondary storage.
File Access Method in Operating System
When a file is used, information is read and accessed into computer memory and there are several ways to access this information of the file.
Some systems provide only one access method for files.
Other systems, such as those of IBM, support many access methods, and choosing the right one for a particular application is a major design problem.
There are three ways to access a file into a computer system: Sequential-Access, Direct Access, Index sequential Method.
File System Implementation in Operating System
A file is a collection of related information.
The file system resides on secondary storage and provides efficient and convenient access to the disk by allowing data to be stored, located, and retrieved.