CSCI 3753 Operating Systems Spring 2005CSCI 3753 AnnouncementsWhat is an Operating System?Slide 4Slide 5Slide 6Slide 7Operating System TrendsSlide 9Slide 10Operating Systems: Key ConceptsSlide 12Operating Systems ResearchWireless Sensor NetworksApplications of Wireless Sensor NetworksMilitary Applications of Sensor NetsCSCI 3753 Operating SystemsSpring 2005Professor Rick HanDepartment of Computer ScienceUniversity of Colorado at BoulderCSCI 3753 Announcements•Who am I?•Review of syllabus•TA introduces first programming shell assignment (similar to lab exercise 2.1) and CSEL logistics•Introduction to Operating Systems•Read chapters 1 and 2 in the textbookWhat is an Operating System?•Windows, Linux•What is an application?–Powerpoint, Realplayer•What is hardware?•An operating system is a layer of software between applications and hardwareApplicationsOperating SystemHardwareWhat is an Operating System?•An operating system is a layer of software between many applications and diverse hardware that–helps to better manage the hardware for an application•otherwise an application saving a file to disk would have to know how the disk operates–helps to share resources and isolate access to resources between multiple applicationsApp3Operating SystemDisk Memory CPU Display MouseApp2App1I/OWhat is an Operating System?•A PC operating system consists of multiple components–scheduler–virtual memory system–file system–other...App3Disk Memory CPU Display MouseApp2App1I/O SchedulerVMFileSystem OS“Kernel”System Libraries and Tools(Compilers, Shells, GUIs)What is an Operating System?App3DiskMemory CPUDisplay MouseApp2App1I/O SchedulerVMFileSystem OS“Kernel”System call API–160 in LinuxDevice driver “API”Posix, Win32,Java, C library APINote: different OS kernels cansupport the same system call APIOS?What is an Operating System?•Distributed Operating Systems–Networked File System–OS adds TCP/IP Network Stack–Device driver support for Networking cardsOSHWApp1 App2 App3NetworkingHWNetworkingStackOSHWApp1 App2 App3NetworkingHWNetworkingStackNetworke.g. Internet, or Ethernet, or WiFi•Examples:–App1 is a distributed client server app, e.g. App1 on left is Web browser, App1 on right is Web serverOperating System Trends•Hardware has evolved quickly - OS must adjust–Moore’s Law applies to CPU speed and/or memory size: doubles every 18 months => exponential!–But Moore’s Law doesn’t apply to disk access speed or to battery life–Diverse devices with high bandwidth requirementsStorage Evolution:Punch cardstores code1950s-80sTape Drive1950s-80sDisk Drive1960s-2000sFlash Drivealready at 1 GB @ $60 => OS disk scheduling obsolete????Operating System Trends•Hardware support for operating systems has evolved too–Mode bit support in CPU•user mode vs. kernel/supervisor mode•early PCs did not have this support•Today’s embedded microcontrollers also lack this support–Page faulting hardware and MMU–Lack of such HW support can allow user programs to accidentally or maliciously overwrite OS kernel code!Operating System Trends•Proliferation of OSs on large scale and small scale and across features–Multi-processor OSs - scaling up–Cell phone OSs - scaling down–Real-Time OS for Embedded and Multimedia SystemsOperating Systems: Key Concepts•Multiprogramming–when CPU idle (e.g. blocked on I/O), run another program => improved CPU utilization1. batch mode - running jobs or programs sequentially, one after the other 2. Time sharing and concurrency - finely interleaved sharing of CPU•useful to give impression of interactivity!Operating Systems: Key Concepts•Time-sharing examples–multiple processes sharing time locally on a CPU–multiple user terminals remotely sharing processing time with a central server•keystroke delayOperating Systems Research•Papers are published at premier OS conferences like:–ACM SOSP 2005 (Symposium on Operating Systems Principles) - http://www.sosp-20.com/–USENIX OSDI 2004 (Operating System Design and Implementation) - http://www.usenix.org/events/osdi04/•Secure Operating Systems•Wireless Sensor NetworksWireless Sensor Networks•Groups of sensor nodes connected by a wireless networking fabric•Sensor nodes consist of CPU/memory, radio, sensors, and power units•Monitor environmentInternetInternet•Self-configure into wireless multi-hop networkApplications of Wireless Sensor Networks•Nature•Wildlife – Great Duck Island (Berkeley 2002)•Home•Security (commercial)•Medical - Assistive Technology (BP Visualization Center, L3D, Ga Tech)•Mobile/Robotic WSANs•Habitat – San Jacinto Nature Preserve (UCLA)•Monitor atmosphere (NCAR)Military Applications of Sensor Nets•Battlefield monitoring•Sound, heat, metal, vibration•Deployed in Vietnam, Afghanistan, Iraq•REMBASS II, UGS, …BasestationWireless sensor network•MANTIS Research Project at University of Colorado at Boulder, Dept Computer Science–Professor Rick Han–10 undergraduate and graduate students–http://mantis.cs.colorado.edu•Designed the MANTIS OS for micro sensor nodes - multithreaded, in C•Designed the ELF flash file system for micro sensor