Design principles of linux operating system

Posted on January 29, 2015 Updated on December 22, 2017 Design Principles Linux is a multiuser, multitasking system with a full set of UNIX-compatible tools. Its file system adheres to traditional UNIX semantics, and it fully implements the standard UNIX networking model. Linux is designed to be compliant with the relevant POSIX documents; at least two Linux distributions have achieved official POSIX certification. The Linux programming interface adheres to the SVR4 UNIX semantics, rather than to BSD behavior. As PCs became more powerful and as memory and hard disks became cheaper, the original, minimalist Linux kernels grew to implement more UNIX functionality. Speed and efficiency are still important design goals, but much recent and current work on Linux has concentrated on a third major design goal: standardization. One of the prices paid for the diversity of UNIX implementations currently available is that source code written for one may not necessarily compile or run correctly on another. Even when the same system calls are present on two different UNIX systems, they do not necessarily behave in exactly the same way. Linux is designed to be compliant with the relevant POSIX documents; at least two Linux distributions have achieved official POSIX certification. 1) Components of a Linux System The Linux system has three main bodies of code, in sequence with, most conventional UNIX implementations. 1- THE KERNEL: “The kernel” is in charge for maintaining all the vital a...

The Unix philosophy, originated by The Unix philosophy emphasizes building simple, compact, clear, modular, and Origin [ ] The Unix philosophy is documented by • Make each program do one thing well. To do a new job, build afresh rather than complicate old programs by adding new "features". • Expect the output of every program to become the input to another, as yet unknown, program. Don't clutter output with extraneous information. Avoid stringently columnar or binary input formats. Don't insist on interactive input. • Design and build software, even operating systems, to be tried early, ideally within weeks. Don't hesitate to throw away the clumsy parts and rebuild them. • Use tools in preference to unskilled help to lighten a programming task, even if you have to detour to build the tools and expect to throw some of them out after you've finished using them. It was later summarized by • Write programs that do one thing and do it well. • Write programs to work together. • Write programs to handle text streams, because that is a universal interface. In their award-winning • Make it easy to write, test, and run programs. • Interactive use instead of • • The UNIX Programming Environment [ ] In their preface to the 1984 book, Even though the UNIX system introduces a number of innovative programs and techniques, no single program or idea makes it work well. Instead, what makes it effective is the approach to programming, a philosophy of using the computer. Although that philoso...

Design Principles � Linux is a multiuser, multitasking system with a full set of UNIX-compatible tools � Its file system adheres to traditional UNIX semantics, and it fully implements the standard UNIX networking model � Main design goals are speed, efficiency, and standardization � Linux is designed to be compliant with the relevant POSIX documents; at least two Linux distributions have achieved official POSIX certification � � Supports Pthreads and a subset of POSIX real-time process control The Linux programming interface adheres to the SVR 4 UNIX semantics, rather than to BSD behavior Components of a Linux System n Like most UNIX implementations, Linux is composed of three main bodies of code; the most important distinction between the kernel and all other components. n The kernel is responsible for maintaining the important abstractions of the operating system l Kernel code executes in kernel mode with full access to all the physical resources of the computer l All kernel code and data structures are kept in the same single address space Components of a Linux System (Cont. ) � The system libraries define a standard set of functions through which applications interact with the kernel, and which implement much of the operating-system functionality that does not need the full privileges of kernel code � The system utilities perform individual specialized management tasks � User-mode programs rich and varied, including multiple shells like the bourne-again (bash)

Design Principles in Linux OS -> Linux is a multi-user, multi-tasking system with a full set of UNIX-compatible tools. -> The Linux file system follows the traditional UNIX semantics, and the UNIX standard network model is implemented as a whole. The internal characteristics of Linux design have been influenced by the history of the development of this operating system. -> Main design goals are speed, efficiency, and standardization. -> As a result of the development of PC technology, the Linux kernel is also becoming more complete in implementing UNIX functions. Fast and efficient are important design goals, but lately the concentration of Linux development has focused more on the third design goal, standardization. The POSIX standard consists of a collection of specifications from different aspects of operating system behavior. There are POSIX documents for ordinary operating system functions and for extensions such as processes for threads and real-time operations. Linux is designed to fit the relevant POSIX documents; there are at least two Linux distributions that have received POSIX official certification. -> Because Linux provides a standard interface to programmers and users, Linux does not make many surprises to anyone who is familiar with UNIX. But the Linux programming interface refers to the UNIX SVR4 semantics rather than BSD behavior. A different collection of libraries is available to implement the BSD semantics in places where the two behaviors are very dif...

Posted on January 29, 2015 Updated on December 22, 2017 Design Principles Linux is a multiuser, multitasking system with a full set of UNIX-compatible tools. Its file system adheres to traditional UNIX semantics, and it fully implements the standard UNIX networking model. Linux is designed to be compliant with the relevant POSIX documents; at least two Linux distributions have achieved official POSIX certification. The Linux programming interface adheres to the SVR4 UNIX semantics, rather than to BSD behavior. As PCs became more powerful and as memory and hard disks became cheaper, the original, minimalist Linux kernels grew to implement more UNIX functionality. Speed and efficiency are still important design goals, but much recent and current work on Linux has concentrated on a third major design goal: standardization. One of the prices paid for the diversity of UNIX implementations currently available is that source code written for one may not necessarily compile or run correctly on another. Even when the same system calls are present on two different UNIX systems, they do not necessarily behave in exactly the same way. Linux is designed to be compliant with the relevant POSIX documents; at least two Linux distributions have achieved official POSIX certification. 1) Components of a Linux System The Linux system has three main bodies of code, in sequence with, most conventional UNIX implementations. 1- THE KERNEL: “The kernel” is in charge for maintaining all the vital a...

Design Principles in Linux OS -> Linux is a multi-user, multi-tasking system with a full set of UNIX-compatible tools. -> The Linux file system follows the traditional UNIX semantics, and the UNIX standard network model is implemented as a whole. The internal characteristics of Linux design have been influenced by the history of the development of this operating system. -> Main design goals are speed, efficiency, and standardization. -> As a result of the development of PC technology, the Linux kernel is also becoming more complete in implementing UNIX functions. Fast and efficient are important design goals, but lately the concentration of Linux development has focused more on the third design goal, standardization. The POSIX standard consists of a collection of specifications from different aspects of operating system behavior. There are POSIX documents for ordinary operating system functions and for extensions such as processes for threads and real-time operations. Linux is designed to fit the relevant POSIX documents; there are at least two Linux distributions that have received POSIX official certification. -> Because Linux provides a standard interface to programmers and users, Linux does not make many surprises to anyone who is familiar with UNIX. But the Linux programming interface refers to the UNIX SVR4 semantics rather than BSD behavior. A different collection of libraries is available to implement the BSD semantics in places where the two behaviors are very dif...

Design Principles � Linux is a multiuser, multitasking system with a full set of UNIX-compatible tools � Its file system adheres to traditional UNIX semantics, and it fully implements the standard UNIX networking model � Main design goals are speed, efficiency, and standardization � Linux is designed to be compliant with the relevant POSIX documents; at least two Linux distributions have achieved official POSIX certification � � Supports Pthreads and a subset of POSIX real-time process control The Linux programming interface adheres to the SVR 4 UNIX semantics, rather than to BSD behavior Components of a Linux System n Like most UNIX implementations, Linux is composed of three main bodies of code; the most important distinction between the kernel and all other components. n The kernel is responsible for maintaining the important abstractions of the operating system l Kernel code executes in kernel mode with full access to all the physical resources of the computer l All kernel code and data structures are kept in the same single address space Components of a Linux System (Cont. ) � The system libraries define a standard set of functions through which applications interact with the kernel, and which implement much of the operating-system functionality that does not need the full privileges of kernel code � The system utilities perform individual specialized management tasks � User-mode programs rich and varied, including multiple shells like the bourne-again (bash)

The Unix philosophy, originated by The Unix philosophy emphasizes building simple, compact, clear, modular, and Origin [ ] The Unix philosophy is documented by • Make each program do one thing well. To do a new job, build afresh rather than complicate old programs by adding new "features". • Expect the output of every program to become the input to another, as yet unknown, program. Don't clutter output with extraneous information. Avoid stringently columnar or binary input formats. Don't insist on interactive input. • Design and build software, even operating systems, to be tried early, ideally within weeks. Don't hesitate to throw away the clumsy parts and rebuild them. • Use tools in preference to unskilled help to lighten a programming task, even if you have to detour to build the tools and expect to throw some of them out after you've finished using them. It was later summarized by • Write programs that do one thing and do it well. • Write programs to work together. • Write programs to handle text streams, because that is a universal interface. In their award-winning • Make it easy to write, test, and run programs. • Interactive use instead of • • The UNIX Programming Environment [ ] In their preface to the 1984 book, Even though the UNIX system introduces a number of innovative programs and techniques, no single program or idea makes it work well. Instead, what makes it effective is the approach to programming, a philosophy of using the computer. Although that philoso...

Design Principles in Linux OS -> Linux is a multi-user, multi-tasking system with a full set of UNIX-compatible tools. -> The Linux file system follows the traditional UNIX semantics, and the UNIX standard network model is implemented as a whole. The internal characteristics of Linux design have been influenced by the history of the development of this operating system. -> Main design goals are speed, efficiency, and standardization. -> As a result of the development of PC technology, the Linux kernel is also becoming more complete in implementing UNIX functions. Fast and efficient are important design goals, but lately the concentration of Linux development has focused more on the third design goal, standardization. The POSIX standard consists of a collection of specifications from different aspects of operating system behavior. There are POSIX documents for ordinary operating system functions and for extensions such as processes for threads and real-time operations. Linux is designed to fit the relevant POSIX documents; there are at least two Linux distributions that have received POSIX official certification. -> Because Linux provides a standard interface to programmers and users, Linux does not make many surprises to anyone who is familiar with UNIX. But the Linux programming interface refers to the UNIX SVR4 semantics rather than BSD behavior. A different collection of libraries is available to implement the BSD semantics in places where the two behaviors are very dif...

Posted on January 29, 2015 Updated on December 22, 2017 Design Principles Linux is a multiuser, multitasking system with a full set of UNIX-compatible tools. Its file system adheres to traditional UNIX semantics, and it fully implements the standard UNIX networking model. Linux is designed to be compliant with the relevant POSIX documents; at least two Linux distributions have achieved official POSIX certification. The Linux programming interface adheres to the SVR4 UNIX semantics, rather than to BSD behavior. As PCs became more powerful and as memory and hard disks became cheaper, the original, minimalist Linux kernels grew to implement more UNIX functionality. Speed and efficiency are still important design goals, but much recent and current work on Linux has concentrated on a third major design goal: standardization. One of the prices paid for the diversity of UNIX implementations currently available is that source code written for one may not necessarily compile or run correctly on another. Even when the same system calls are present on two different UNIX systems, they do not necessarily behave in exactly the same way. Linux is designed to be compliant with the relevant POSIX documents; at least two Linux distributions have achieved official POSIX certification. 1) Components of a Linux System The Linux system has three main bodies of code, in sequence with, most conventional UNIX implementations. 1- THE KERNEL: “The kernel” is in charge for maintaining all the vital a...