Unix/Linux Operating System

• Mail list of Linux kernel developers
• Command-line interface - Wikipeida
• Fstab - Wikipedia
• (Paper) A study of Linux File System Evolution
• Descript the boot-up sequences of Linux operating system.
• UNIX Tutorial for Begineers
• (Film) Tron a film about the Digital Virtual World.

Operating System

• (Books) "Modern Operating System", A. S. Tanenbaum
• My Non-technical thoughts about Computer Operating System
  • User friendly: For users, Operating System must be User friendly, but there is a huge gap between Programmer friendly and user friendly, that's what the designer/creator/builder of OS ignored or blind to see, and that's the reason why people like Macintosh rather than (UNIX, System V, BSD, MINIX, Linux, MS-DOS, Windows-NT). Another question, what is User friendly, how to define User friendly, In my opinion, a 6 years old child can use it without teaching.
  • Abstraction:

1.Introduction

1.1.Hierarchical Level of Computer System

• A computer system consists of hardware, system programs, and application programs.
  • Computing module -> one or more processors (multi-core/multi-processors/distributed system), related to an important concept: time.
  • Data storage module -> main memory and disks or more complex hierarchical storage system (register, cache(l1,l2,l3), memory, virtual memory, disk, optical storage), related to an important concept: space.
  • Information input module -> keyboard, mouse, others input devices.
  • Information output module -> display, printer, others output devices.
  • Communication module -> network interfaces, others communication devices
• It's all about information processing, in a nutshell, input -> processing (compute, store, communicate) -> output

4.Application programs

• Q: What is application programs?

• A: Application programs like Web browser /Banking system /Airline reservation, these programs are purchased or written by the users to solve their particular problems, such as word processing, spreadsheets, engineering calculations, or storing information in a database.

• Q: Who can write application program? or How much training I need to make me capable to write a application program?

• A: Any one who accept a little computer technology training can do it without understanding to the deep knowledge/concept of computer science. And the people who are only capable to write application program (not too big and complex) is called software developer.

• The definition of application program also define a fact that there will be infinite nubers of application programs. From an old programer's advice, a wisdom is gaven - How you write these program, which programming language you use to write them, they are all doesn't matter. What does matter is the reason why you write these program, and what you's gonna do with these programs.

3.System programs

• Compilers /Editors /Command interpreter (Shell)
• Operating System:

• Programs runnig modes: kernel mode, supervisor mode, user mode.

  • Q: (Concept) What is operating system?

  • A: Whose job is to manage all these devices and provide user programs with a simpler interface to the hardware.

  • Q: (Function) What operating system do?

  • A: (a).Extending the machine by extends the computer’s instruction set. (b).Managing resources (provide for an orderly and controlled allocation of the processors, memories, and I/O devices among the various programs competing for them.) Resource management includes multiplexing (sharing) resources in two way: in time and space

  • Q: Why operating system existed? What is the benifit of operating system?

  • A: (a).Operating system make people simpler to use that brunch of computer hardwares, people who haven't have so much training, professional knowledge, deep understanding to hardware can use computer or write application by using a software layer called operating system instead. (b).Operating system make programmer won't need to involved with detials that need write program to keep track all these components and use them correctly everytime they write a software.

2.Machine language

• (little misunderstanding)
• the hardware and instructions visible to an assembly language programmer form the ISA (Instruction Set Architecture) level. (instruction set, memory organization, I/O, and bus structure)

1.Micro-architecture

• (little misunderstanding)

0.Physical devices

• The lowest level contains physical devices, consisting of integrated circuit chips, wires, power supplies, cathode ray tubes, and similar physical devices. How these are constructed and how they work are the provinces of the electrical engineer.

1.2.History of Operating System

• UNIX
  
  • UNIX -> System V from AT&T and BSD from University at California at Berkeley -> (POSIX standard from IEEE)
  • UNIX -> Minix (Small clone of UNIX) -> Linux (idea from Minix and free production)
    Most of what will be said about UNIX in here thus applies to System V, BSD, MINIX, Linux, and other versions and clones of UNIX as well.

1.3.The Operating System Zoo

• Mainframe Operating Systems

  • These computers distinguish themselves from personal computers in terms of their size and I/O capacity.
  • They processing at a bank or airline reservations.

• Server Operating Systems

  • Servers provide print service, file service, or web service (store webpages, and handle incoming requests)
  • Typical OS are UNIX, Linux, Windows.

• Multiprocessor Operating Systems

  • They connect multiple CPUs into single system, these systems are called parallel computers, multicomputers, or multiprocessors.

• Personal Computer Operating Systems

  • The job of PC OS is provide a good interface to a single user.
  • Widly known are Windows, Macintosh, GNU/Linux Distributions.

• Real-Time Operating Systems

  • Real-Time Operating System are characterized by having time as a key parameter.
  • Hard Real-Time System - If the action absolutely must occur at a certain moment (or within a certain range), we have a hard real-time system. For an example the system in car manufacturing factory.
  • Soft Real-Time System - If missing an occasional deadline is acceptable. Like Digital audio or multimedia system.

• Embedded Operating Systems

  • Embedded systems run on the computers that control devices that are not generally thought of as computers, such as TV sets, microwave ovens, and mobile telephones.
  • Restrictions: Size, Memory, Power.
  • Example: The PDA (Personal Digital Assistant) I used: Sony TG-50, Palm Treo 680 was running PalmOS. The smartphone (Palm Treo Pro 850) I used was running Windows CE (Consumer Electronics).

• Smart Card Operating Systems

  • They are credit card-sized devices containing a CPU chip, some of them can handle only a single function, such as electronic payments.
  • Restrictions: Power, Memory.
  • Some smart cards are Java oriented, which means there is a ROM on the smart card holding a interpreter for the Java Virtual Machine (JVM).

1.4.Computer Hardware Review

• Processors, Memory, I/O Devices, Buses
• Not interested in them now, pass.
• Special Registers in Processors
  • PC (Program Counter): Contain the memory address of the next instruction to be fetched, after that instruction has been fetched, the program counter is updated to point to its successor.
  • SP (Stack Pointer): Point to the top of the current stack in memory. * PSW (Program Status Word): This register contains the condition code bits, which are set by comparison instructions, the CPU priority, the mode (user or kernel), and various other control bits. User programs may normally read the entire PSW but typically may write only some of its fields. The PSW plays an important role in system calls and I/O.

1.5.Operating System Concepts

• Process - A process is basically a program in excution.

Book Content

• 1.Introduction
  • 1.1.What Is An Operating System
  • 1.2.History of Operating System
  • 1.3.The Operating System Zoo
  • 1.4.Computer Hardware Review
  • 1.5.Operating System Concepts