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

Compilers EditorsInterpreters

Office Suite Web 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 1945 - 1955

– Technology: vacuum tubes, plug boards

– Sign up for time, exclusive use of the machine

– Languages: none

– OS: no operating system

• Second generation 1955 - 1965– 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 (2nd Generation)

• Structure of a typical job – 2nd 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

Memory CPUVideo

AdapterDisk

ControllerKeyboardController

MouseController

NetworkAdapter

DisplayMonitor

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

Type Access Time Size

Registers 1 nanosecond < 1KB

Cache 2 nanoseconds 1 MB

Main Memory 10 nanoseconds 256 MB - 4 GB

Disk 10 microseconds 100 GB - 1 TB

Tape 10 seconds 200 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 Functions Device 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.