Review What does an Operating System do Silerschatz and Gavin An OS is Similar to a government Begs the question does a government do anything useful by itself Coordinator and Traffic Cop Manages all resources Settles conflicting requests for resources Prevent errors and improper use of the computer Facilitator Provides facilities that everyone needs Standard Libraries Windowing systems Make application programming easier faster less error prone Some features reflect both tasks E g File system is needed by everyone Facilitator But File system must be Protected Traffic Cop CS162 Operating Systems and Systems Programming Lecture 2 History of the World Parts 1 5 Operating Systems Structures August 31 2005 Prof John Kubiatowicz http inst eecs berkeley edu cs162 8 31 05 Review Virtual Machine Abstraction Application Operating System Hardware Data 2 Code Data Heap Stack Virtual Machine Interface Physical Machine Interface Code Data Heap Stack Stack 1 Heap 1 Code 1 Stack 2 Prog 1 Virtual Address Space 1 Turn hardware software quirks what programmers want need Optimize for convenience utilization security reliability etc Prog 2 Virtual Address Space 2 Data 1 Heap 2 Code 2 OS code For Any OS area e g file systems virtual memory networking scheduling Translation Map 1 Lec 2 3 OS data Translation Map 2 OS heap Stacks What s the hardware interface physical reality What s the application interface nicer abstraction Kubiatowicz CS162 UCB Fall 2005 Lec 2 2 Review Example of Address Translation Software Engineering Problem 8 31 05 Kubiatowicz CS162 UCB Fall 2005 8 31 05 Physical Address Space Kubiatowicz CS162 UCB Fall 2005 Lec 2 4 Review Dual Mode Operation Goals for Today Hardware provides at least two modes History of Operating Systems Kernel mode or supervisor or protected User mode Normal programs executed Really a history of resource driven choices Some instructions ops prohibited in user mode Example cannot modify page tables in user mode Operating Systems Structures Operating Systems Organizations Attempt to modify Exception generated Transitions from user mode to kernel mode System Calls Interrupts Other exceptions Note Some slides and or pictures in the following are adapted from slides 2005 Silberschatz Galvin and Gagne 8 31 05 Kubiatowicz CS162 UCB Fall 2005 Lec 2 5 8 31 05 CPU MHz Cycles inst 1981 10 3 10 2005 3800 0 25 0 5 Factor 380 6 40 DRAM capacity 128KB 4GB 32 768 Disk capacity 10MB 1TB 100 000 Net bandwidth 9600 b s 1 Gb s 110 000 addr bits 16 32 2 users machine 10s 1 0 1 Price 25 000 4 000 0 2 The machine designed by Drs Eckert and Mauchly was a monstrosity When it was finished the ENIAC filled an entire room weighed thirty tons and consumed two hundred kilowatts of power http ei cs vt edu history ENIAC Richey HTML Typical academic computer 1981 vs 2005 Kubiatowicz CS162 UCB Fall 2005 Lec 2 6 Dawn of time ENIAC 1945 1955 Moore s law change 8 31 05 Kubiatowicz CS162 UCB Fall 2005 Lec 2 7 8 31 05 Kubiatowicz CS162 UCB Fall 2005 Lec 2 8 History Phase 1 1948 1970 Hardware Expensive Humans Cheap Core Memories 1950s 60s When computers cost millions of s optimize for more efficient use of the hardware Lack of interaction between user and computer The first magnetic core memory from the IBM 405 Alphabetical Accounting Machine User at console one user at a time Batch monitor load program run print Optimize to better use hardware When user thinking at console computer idle BAD Feed computer batches and make users wait Autograder for this course is similar No protection what if batch program has bug 8 31 05 Kubiatowicz CS162 UCB Fall 2005 Lec 2 9 Core Memory stored data as magnetization in iron rings Iron cores woven into a 2 dimensional mesh of wires Origin of the term Dump Core Rumor that IBM consulted Life Saver company See http www columbia edu acis history core html 8 31 05 History Phase 1 late 60s early 70s Data channels Interrupts overlap I O and compute Kubiatowicz CS162 UCB Fall 2005 Lec 2 10 A Multics System Circa 1976 DMA Direct Memory Access for I O devices I O can be completed asynchronously Multiprogramming several programs run simultaneously Small jobs not delayed by large jobs More overlap between I O and CPU Need memory protection between programs and or OS Complexity gets out of hand Multics announced in 1963 ran in 1969 www multicians org lists 1777 people who contributed to Multics Probably 30 40 core developers Turing award lecture from Fernando Corbat key researcher On building systems that will fail OS 360 released with 1000 known bugs APARs Anomalous Program Activity Report OS finally becomes and important science How to deal with complexity UNIX based onKubiatowicz MulticsCS162 but UCB vastly simplified 8 31 05 Fall 2005 Lec 2 11 The 6180 at MIT IPC skin doors open circa 1976 We usually ran the machine with doors open so the operators could see the AQ register display which gave you an idea of the machine load and for convenient access to the EXECUTE button which the operator would push to enter BOS if the machine crashed http www multicians org multics stories html 8 31 05 Kubiatowicz CS162 UCB Fall 2005 Lec 2 12 History Phase 2 1970 1985 Hardware Cheaper Humans Expensive Early Disk History 1979 7 7 Mbit sq in 2 300 MBytes Response time 1973 1 7 Mbit sq in 140 MBytes Computers available for tens of thousands of dollars instead of millions OS Technology maturing stabilizing Interactive timesharing Use cheap terminals 1000 to let multiple users interact with the system at the same time Sacrifice CPU time to get better response time Users do debugging editing and email online Problem Thrashing Performance very non linear response with load Thrashing caused by many factors including Swapping queueing source New York Times 2 23 98 page C3 Makers of disk drives crowd even more data into even smaller spaces 8 31 05 Kubiatowicz CS162 UCB Fall 2005 Lec 2 13 Users 8 31 05 Administriva Time for Project Signup Time 101 Tu 1 00 2 00P 102 103 104 105 W 10 00 11 00A W 11 00 12 00P W 1 00 2 00P W 2 00 3 00P 8 31 05 Location 310 Hearst Mining 2 Evans 85 Evans 85 Evans 85 Evans Kubiatowicz CS162 UCB Fall 2005 Lec 2 14 Administrivia 2 Project Signup The group signup page is now working Only submit once per group Everyone in group must have logged into their cs162 xx accounts before you register the group Make sure that you select at least 2 potential sections Due date Wednesday 9 7 by 11 59pm Next week go to your pre assigned section Section Kubiatowicz CS162 UCB Fall 2005 TA
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