History Phase 4 1988 Internet CS162 Operating Systems and Systems Programming Lecture 3 Developed by the research community Based on open standard Internet Protocol Internet Engineering Task Force IETF Technical basis for many other types of networks Intranet enterprise IP network Concurrency Processes Threads and Address Spaces Services Provided by the Internet Shared access to computing resources telnet 1970 s Shared access to data files FTP NFS AFS 1980 s Communication medium over which people interact January 26 2010 Ion Stoica http inst eecs berkeley edu cs162 email 1980 s on line chat rooms instant messaging 1990 s audio video 1990 s early 00 s Medium for information dissemination USENET 1980 s WWW 1990 s Audio video late 90 s early 00 s replacing radio TV File sharing late 90 s early 00 s 1 26 10 Network Cloud CS162 UCB Spring 2010 Lec 3 2 Regional Nets Backbone Regional Net Regional Net Regional Net Backbone Regional Net Regional Net LAN LAN Regional Net LAN LAN Local Area Network 1 26 10 CS162 UCB Spring 2010 1 26 10 Lec 3 3 Page 1 CS162 UCB Spring 2010 Lec 3 4 Backbones NAPs ISPs NAP Backbones Business ISP LAN DSL Always on ISP ISP ISP Computers Inside the Core ISP CS162 UCB Spring 2010 1 26 10 The Morris Internet Worm 1988 LAN Dial up CS162 UCB Spring 2010 Lec 3 6 E mail message with VBScript simplified Visual Basic Relies on Windows Scripting Host Enabled by default in Win98 2000 User clicks on attachment infected Author Robert Morris a first year Cornell grad student Launched close of Workday on November 2 1988 Within a few hours of release it consumed resources to the point of bringing down infected machines E mails itself to everyone in Outlook address book Replaces some files with a copy of itself Searches all drives Techniques Exploited UNIX networking features remote access Bugs in finger buffer overflow and sendmail programs debug mode allowed remote login Dictionary lookup based password cracking Grappling hook program uploaded main worm program CS162 UCB Spring 2010 LAN AOL LoveLetter Virus May 2000 Internet worm Self reproducing 1 26 10 Sprint LAN Lec 3 5 ISP Satellite Fixed Wireless Cell Cell Cell Dial up NAP NAP Cingular ISP Internet Service Provide NAP Network Access Point 1 26 10 home Covad Consumer ISP LAN LAN NAP Cable Head Ends Downloads password cracking program 60 80 of US companies infected and 100K European servers 1 26 10 Lec 3 7 Page 2 CS162 UCB Spring 2010 Lec 3 8 History Phase 5 1995 Mobile Systems Datacenter is the Computer Ubiquitous Mobile Devices Laptops PDAs phones Small portable and inexpensive From Luiz Barroso s talk at RAD Lab 12 11 Google program Web search Gmail Google computer Many computers person Limited capabilities memory CPU power etc Wireless Wide Area Networking Leveraging the infrastructure Huge distributed pool of resources extend devices Traditional computers split into pieces Wireless keyboards mice CPU distributed storage remote Thousands of computers networking storage Peer to peer systems Warehouse sized facilities and workloads may be unusual today but are likely to be more common in the next few years Many devices with equal responsibilities work together Components of Operating System spread across globe 1 26 10 CS162 UCB Spring 2010 1 26 10 Lec 3 9 CS162 UCB Spring 2010 Lec 3 10 Implementation Issues How is the OS implemented Migration of Operating System Concepts and Features Policy vs Mechanism Policy What do you want to do Mechanism How are you going to do it Should be separated since both change Algorithms used Linear Tree based Log Structured etc Event models used threads vs event loops Backward compatability issues Very important for Windows 2000 XP System generation configuration How to make generic OS fit on specific hardware 1 26 10 CS162 UCB Spring 2010 1 26 10 Lec 3 11 Page 3 CS162 UCB Spring 2010 Lec 3 12 Administriva Time for Project Signup Administrivia 2 Section assignments are done Cs162 xx accounts Watch for section assignments after the class Attend new sections tomorrow Make sure you got an account form If you haven t logged in yet you need to do so Project Signup Watch Group Section Assignment Link 4 5 members to a group Tuesday Start Project 1 Go to Nachos page and start reading up Note that all the Nachos code will be printed in your reader TBA Everyone in group must be able to actually attend same section Only submit once per group Everyone in group must have logged into their cs162 xx accounts once before you register the group Due Friday 1 29 by 11 59pm Section 101 Time W 10 00A 11 00A Location 2 Evans TA Matei Zaharia 102 W 2 00P 3 00P 75 Evans Andy Konwinski 103 W 3 00P 4 00P 2 Evans Ben Hindman 1 26 10 CS162 UCB Spring 2010 1 26 10 Lec 3 13 Goals for Today CS162 UCB Spring 2010 Lec 3 14 Concurrency How do we provide multiprogramming What are Processes How are they related to Threads and Address Spaces Thread of execution Independent Fetch Decode Execute loop Operating in some Address space Uniprogramming one thread at a time MS DOS early Macintosh Batch processing Easier for operating system builder Get rid concurrency by definition Does this make sense for personal computers Multiprogramming more than one thread at a time Multics UNIX Linux OS 2 Windows NT 2000 XP 7 Mac OS X Often called multitasking but multitasking has other meanings talk about this later Note Some slides and or pictures in the following are adapted from slides 2005 Silberschatz Galvin and Gagne Gagne Many slides generated by John Kubiatowicz 1 26 10 CS162 UCB Spring 2010 ManyCore Multiprogramming right 1 26 10 Lec 3 15 Page 4 CS162 UCB Spring 2010 Lec 3 16 The Basic Problem of Concurrency Recall 61C What happens during execution The basic problem of concurrency involves resources Data1 Fetch Data0 Exec Inst237 Inst236 Inst5 Execution sequence Inst4 Fetch Instruction at PC Inst3 Decode Inst2 Execute possibly using registers Inst1 Write results to registers mem Inst0 Hardware single CPU single DRAM single I O devices Multiprogramming API users think they have exclusive access to shared resources OS Has to coordinate all activity Multiple users I O interrupts How can it keep all these things straight Basic Idea Use Virtual Machine abstraction Decompose hard problem into simpler ones Abstract the notion of an executing program Then worry about multiplexing these abstract machines Dijkstra did this for the THE system Few thousand lines vs 1 million lines in OS 360 1K bugs 1 26 10 CS162 UCB Spring 2010 1 26 10 Lec 3 17
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