Introduction to Linux History and systems

This section focuses on the development of the operating system, changes, the composition of the operating system and the branch of Linux

The Birth of Unix:

The Bell lab in the US, GE and MIT have partnered to develop a multi-user, multitasking computer environment that facilitates the sharing of hardware and software resources, namely Multics, after 5 years of hard-to-reach failure.

Thompson and Ritchie compiled a space travelling game, and found an abandoned PDP-7, in order to play the game, he developed an understanding of the Multics project by a Simple file system (later developed into S5FS), A process subsystem, a simple shell command compiler, and some utilities, the UNIX system

In 1971, Ritchie and Thompson migrated the system to PDP-11, adding word-processing tools, including the ED editor, runoff tools, and so on, in November, when Thompson and Ritchie published the Unix Programer ' s Manual "First edition

Ritchie upgrades the B language, adds complex processing capabilities to many advanced languages, and has the ability to manipulate binary and character directly in machine language

In February 1973, the addition of CC, C language compiler in Unix, the same year Ritchie rewritten Unix in C language, making it a very good transplant.

Because of anti-monopoly, at and T free to universities and research institutions to provide UNIX software and source code. Lead to UNIX prevalence.

At/T later released System 3 (first commercial version)

The development of Desktops

1, 1981 PC was born and started to develop, but the machine and operating system (CP/M) are very expensive, when the CPU is mainly Intel 80386, 80486 and so on

2. The birth and development of Microsoft

Microsoft established: Established as a basic compiler, Xenix (Unix kind) for sale.

Bill Gates sells an operating system developed by a programmer for 4 months and buys it to IBM for sale on IBM machines with a cheap license bundle, the DOS system.

A graphical interface-based Windows operating system was later released, representing 95, 98, etc.

An improved Windows NT system and server system based on VMS (Unix)

3. The birth and development of Apple

Jobs is based on the BSD operating system and the Power PC core PC.

acquired the GUI and mouse developed by the Park Lab from Xerox and integrated it on Apple's operating system.

The film "The Legend of Silicon Valley"

The advent and development of Linux

Professor Andrew of the Netherlands has written a MINIX system for students to use and teach.

Linus, in his own 80386-coat minix, but feel the migration trouble, so he rewritten a system through Linux, and published online, so that everyone free download and perfect

In the 80 's, Stallman advocated freedom movement, thinking that the procedure was human. GNU was founded, using the GPL protocol

Gnu:gnu is not Unix

Gpl:general Public Licence Common license requires that all source code involving the GPL be free and open

GNU has produced software such as Gcc,emacs.

Gnu/linux Rapid Development, 91 0.1, 94 1.0, now 3.7.9 official website: www.kernel.org The official site provides the source code

For Linux to work, it has to rely on GNU's various software. So Linux should actually be called Gnu/linux.

Their kernel is all source code.

Linux Source-code formats are compiled into a common format on a common computer platform, allowing others to install the Linux systems they use on most platforms. Called Linux Publishers

1993 Redhat Company was established, integrated RPM software Management Pack, released personal version of 1.0-9.0 (terminated in 2003, donated to Fedora), Enterprise Edition 3.0--6.3,www.redhat.com

Redhat-based Fedora and Mandriva (graphical interface)

Centos:community Enterprise OS, Community Red Hat System, fully compatible with Red Hat. Compile the patches released by Red Hat into patches that users can use.

1991 SLS

1992 Debian (the only Linux version not commercially affected), developing the DPT Package Manager

European high-end users use more, the entry is difficult, but good

Based on Debian derived Ubuntu and mint

Three German university students founded SuSE, the interface gorgeous, powerful. After being acquired by Novell Corporation , the open SUSE

Operating system hardware and software architecture, mainly including the system hardware architecture, operating system architecture

System Hardware Architecture:

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The system hardware mainly has five parts: the arithmetic, the controller, the storage device, the input device, the output device

CPU consists of an operator, a controller, a register, a primary cache, and a level two cache

Operators: primarily responsible for data operations

Controller: Mainly control and parsing instructions.

Register and first-level cache with level two cache: all for data and instructions, registers are expensive, and caches are more expensive.

CPU clock cycle: The time that a calculation is used, that is, the manifestation of computing power

Programmable Interrupt controller: divided into South and North Bridge, is responsible for connecting external equipment and CPU equipment, control interrupt, instruction transmission,

North Bridge: Also known as high-speed bus controller, responsible for connecting memory, cup and South Bridges

South Bridge: Low Speed Bus Controller

Memory: RAM: Random access memory ROM: Read-only memory

Data line is divided into: Bus and control bus, now multiplexing

Memory: storage space, data, and temporary storage of instructions. The 32-bit CPU supports only 2 of the 32-address space and supports up to 4G of memory. Virtual address space

I/O devices: divided into input devices and output devices

Input device: keyboard, mouse.  Output device: Monitor. discs, floppy disks, and hard disks are auxiliary storage devices, which are output and input devices.

Operating system: Infrastructure

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A complete system is composed of hardware and software, hardware is the basis of the operating system, software is to let the hard drive according to the requirements of the university's work.

Early computers were fed by paper tape, the display was output, and the computer was very expensive. Later invented the disk machine, greatly speeding up the computer input and output work. and imported a multi-tasking system.

Multi-tasking system can control multiple processes at the same time, which requires reasonable management of hardware resources, i.e. operating system

1. Self-time management of CPU resources

2. Segmented management of memory resources

3, the task of life cycle management, that is, process management, that is, program start, stop, end and resource recovery and switching work

4. Control and management of system interruption process

Operating system is also a professional software, responsible for the coordination of hardware resources and programs start, stop and switch work

Hardware control requires programming of the hardware:

Machine language: A resource consisting of 1 and 0 that can be identified and used by hardware.

Microcode: Written by assembler, edited into machine language by compiler

Advanced languages: JAVA, C and other languages

Operating system: The operating system we are talking about is actually made up of kernel, libraries, and a series of software

Kernel: Primary hardware resource invocation (System call). All program interactions with hardware resources must be done through kernel. Does not provide the specific function, the hardware provides the computing resources abstraction, provides to the upper layer other software to use. The resource invocation of the kernel is called system call.

Main functions: Process management, memory management, file system, network function, hardware drive, security mechanism.

Library: Kernel calls and feedback to resources are particularly low-level calls, so the feedback data needs to be further processed. Encapsulates one or more system invocation functions into a more advanced system invocation interface. (The same program can not be run on different operating systems, because the different operating system of the library, the need for program modification). A library is an executable program, but it cannot be executed independently and must be called before it can be executed.

Api:application program Interface

Shell: The system is displayed to the user through a human-acceptable interface. Divided into command line interface and graphical interface

Program: Made up of instructions and data

Boot up: Bootstrap, hardware logic----ROM----memory----CPU----Check device BIOS

Hardware and operating system platforms

CPU hardware is divided into the following system architectures:

ARM: UK Acorn computer mainly for ARM chip design, Qualcomm and Samsung and other production and manufacturing, with high performance and low energy consumption, suitable for mobile devices

X86 32-bit AMD and Intel

X86 64-bit AMD

Itanium series Inter (Acquisition)

Alphe

UltraSparc Sun Ltd.

Power IBM design and production, high-performance, high-priced

M68000 namely M68k,moto production, can static rage.

PowerPC is produced by companies such as IBM and Apple.

The operating system that corresponds to the CPU

Windows

Linux

Unix:hp-ux Solaris (SUN) AIX (IBM) Sco-unix UnixWare

UNIX is basically its own operating system that only runs on its own server.

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Introduction to Linux History and systems