CS 6560 Operating System Design Lecture 1

Overview 1.1 What is an operating system 1.2 History of operating systems 1.3 The operating system zoo 1.4 Computer hardware review 1.5 System Calls

Some References

Core References

Computer System A Computer System Consists of –Hardware Internal: CPU, CPU support, memory, bus, adapters, disk drives External: display, keyboard, disk drives, printers –Software Firmware Operating System Other System Software Application Programs

A Computer System A computer system consists of –hardware –system programs –application programs Physical devices Microprogramming system Machine Language interface Kernel CompilersEditorsInterpreters Office SuiteWeb Browsers Hardware Operating System Applications Multimedia tools

What is an Operating System It is an extended machine –Hides the messy details which must be performed –Presents user with a virtual machine, easier to use It is a resource manager –Each program gets time with the resources –Each program gets space on the resources

History of Computer Systems First generation –Technology: vacuum tubes, plug boards –Sign up for time, exclusive use of the machine –Languages: none –OS: no operating system Second generation –Technology: transistors, punch cards –Mainframes –Languages: FORTRAN, COBOL, –Jobs –OS: batch systems, libraries Third generation 1965 – 1980 –Technology: Integrated Circuits –Large mainframes and smaller machines (IBM 360 family) –Minicomputers (DEC) –OS: multiprogramming, large systems (multipart), batch and timesharing, emergence of Unix Fourth generation 1980 – present –Technology: Mass production of integrated circuits (chips and boards) –Personal computers/servers/Internet –OS: embedded -> supercomputer, CP/M -> Windows, PARC->Macintosh, Unix -> Linux/Solaris

History of Operating Systems (2 nd Generation) Structure of a typical job – 2 nd generation

System Life Cycle Ontogeny Recapitulates Phylogeny (Ernst Haeckel, 1866) Ontogeny = "the development of an individual organism from egg to maturity” Recapitulates = “repeats” Phylogeny = “the development over time of a kind of organism”

The Operating System Taxonomy Mainframe operating systems Server operating systems Multiprocessor operating systems Personal computer operating systems Real-time operating systems Embedded operating systems Smart card operating systems Virtual systems Clusters and grids

Computer Insides

Computer Hardware Components of a typical computer Bus MemoryCPU Video Adapter Disk Controller Keyboard Controller Mouse Controller Network Adapter Display Monitor Hard Disks DVD/CD Disk Keyboard Mouse

Types of Devices Categories –CPU –Memory –Clock –Bus control: Arbitration, Interrupt, DMA –Block devices –Character –Memory mapped –Networking Performance Wide range from 10 byes/sec (keyboard) to several hundred megabytes/sec (PCI bus)

CPU Architecture Memory Cache Instruction Decoding Arithmetic Logic Units Floating Point Unit Internal Buses

Computer Hardware Review Structure of a Pentium-based system

CPU Registers Program counter Stack Pointer Program Status Word Data Address

Computer Hardware - Memory One base-limit pair and two base-limit pairs

Computer Hardware Typical memory hierarchy –numbers shown are rough approximations TypeAccess TimeSize Registers1 nanosecond< 1KB Cache2 nanoseconds1 MB Main Memory10 nanoseconds256 MB - 4 GB Disk10 microseconds100 GB - 1 TB Tape10 seconds200 GB - ?

Secondary and Third Level Storage

Disks Types –Magnetic (fixed and removable, internal and external, RAID) –Optical (CD-ROM, CD-R, DVD) Interfaces –IDE, SCSI, USB, Fiber Channel, etc. Recall basic structure –Cylinders, tracks, sectors –Issues: Cylinder skew, sector interleaving, virtual geometry, logical block addressing –Architecture Integrated disk drive (drive with embedded computer system) Bus-interface controller (interfaces between system bus and cable to integrated disk drive)

Computer Hardware Review Structure of a disk drive

Examples of Disks Tanenbaum, MOS

Computer Hardware Review (a) Steps in starting an I/O device and getting interrupt (b) How the CPU is interrupted (a)(b)

Kernel-based Systems (Monolithic) System calls File Management Process Management Interprocess Communication Management Memory Management General Purpose FunctionsDevice tables Device Drivers

System Calls Some Win32 API calls

Steps for System Call 1-3) Push registers on stack 4) call library function 5) place function # in register (or stack) 6) execute TRAP instruction 7) dispatch to call handler 8) runs a handler 9) returns to library function 10) returns back to program 11) cleans up the stack

Steps in Making a System Call There are 11 steps in making the system call read (fd, buffer, nbytes)

Operating System Concepts A process tree –A created two child processes, B and C –B created three child processes, D, E, and F

Operating System Concepts Two processes connected by a pipe

Operating System Concepts Typical file and directory system for a university department

Operating System Concepts (a) A potential deadlock. (b) an actual deadlock.