CS4500/5500 Operating Systems Introduction

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1 Operating Systems Intrductin Yanyan Zhuang Department f Cmputer Science UC. Clrad Springs Ref. MOS4E, OS@Austin, Clumbia, UWisc

2 Intr f Intr Yanyan Zhuang PhD in netwrk systems yzhuang@uccs.edu Office hurs M/W: 6-6:45pm Canvas: annuncement, prject, assignment, exams 2 Ref. MOS4E, OS@Austin, Clumbia, UWisc

3 Outline Why study Operating Systems? What will yu learn? Lectures, Assignments, Prjects, Exams Curse plicy OS verview 3 Ref. MOS4E, OS@Austin, Clumbia, UWisc

4 Why Study Operating Systems? The mst cmplex sftware ~ 8 millin lines f cde in Linux 4 Ref. MOS4E, OS@Austin, Clumbia, UWisc

5 Why Study Operating Systems? The mst cmplex sftware ~ 8 millin lines f cde in Linux The mst fundamental sftware OSes are almst everywhere, e.g., supercmputer, PC, phne 5 Ref. MOS4E, OS@Austin, Clumbia, UWisc

6 Why Study Operating Systems? The mst cmplex sftware ~ 8 millin lines f cde in Linux The mst fundamental sftware OSes are almst everywhere, e.g., supercmputer, PC, phne By studying OS, yu will Learn hw cmputers wrk } Gain a gd understanding f OS and hardware Learn abut system design } Simplicity, prtability, perfrmance, and trade-ffs 6 Ref. MOS4E, OS@Austin, Clumbia, UWisc

7 What Will Yu Learn? Hardware abstractin Prcesses, threads, files Resurce management CPU scheduling, memry management, file systems Crdinatin Multiple prgrams and users Fairness and efficiency 7 Ref. MOS4E, OS@Austin, Clumbia, UWisc

8 Lectures, Assignments, Prjects, Exams Lectures Mnday and Wednesday ENGR 107 Hmewrk 2 written assignments: individual Prjects 4 prgramming assignments 2 students team up (1 r 3 peple please me, changing team allwed) Exams (clsed bk, ne letter-size cheat sheet) Midterm: in class, late Octber Final: Dec 12 8 Ref. MOS4E, OS@Austin, Clumbia, UWisc

9 Prjects are dne n VMs VM setup Desktp vs. minimal Minimal nly gives a terminal, n GUI D nt create mre than 2 VMs Limited IP addresses available t the class If yu d like t abandn a VM, rename it delete-me Sharing a VM amng team members is k UC. Clrad Springs Ref. MOS4E, OS@Austin, Clumbia, UWisc

10 Late Plicy Days late / pints ff 1-3days / days / days / days / days / -100 Final submissin Midnight Friday, last week f class All utstanding assignments/prjects must be submitted 10 Ref. MOS4E, OS@Austin, Clumbia, UWisc

11 Grading Plicy Grading percentage Hmewrk assignments: 16% Prjects: 36% Midterm: 18% Final exam: 25% Attendance: 5% 11 Ref. MOS4E, Clumbia, UWisc

12 Where t get help? Ask questins in class Read slides Office hurs M/W 6:00--6:45pm, ENGR 184 TA Extra ffice hurs befre exams David Stut (dstut2@uccs.edu) Tutring: Mndays 10AM 1PM, ENGR 232 Recitatin: Fridays 4 6PM, ENGR Ref. MOS4E, OS@Austin, Clumbia, UWisc

13 OS Overview 13 Ref. MOS4E, Clumbia, UWisc

14 What is an Operating System? A cmputer system cnsists f hardware system prgrams applicatin prgrams 14 Ref. MOS4E, OS@Austin, Clumbia, UWisc

15 What des an Operating System d? It is an extended (r virtual) machine Hides the messy details which must be perfrmed Presents user with a virtual machine, easier t use Prvides prtectin 15 Ref. MOS4E, OS@Austin, Clumbia, UWisc

16 The Operating System as an Extended Machine fprintf(fd, %d, data); write(fd, buffer, cunt); file->f_p->write(file, buf, cunt, ps); lad(blck, length, device); seek(device, track); ut(device, sectr); 16 Ref. MOS4E, Clumbia, UWisc

17 What des an Operating System d? It is an extended (r virtual) machine Hides the messy details which must be perfrmed Presents user with a virtual machine, easier t use Prvides prtectin It is a resurce manager Each prgram gets time with the resurce, e.g., CPU Each prgram gets space n the resurce, e.g., MEM 17 Ref. MOS4E, OS@Austin, Clumbia, UWisc

18 The Operating System as a Resurce Manager Prgram 1 Prgram i Prgram n Extended Machine Interface (Resurce Abstractin) OS Resurce Sharing Time-multiplexed CPU resurce Space-multiplexed memry resurce 18 Ref. MOS4E, OS@Austin, Clumbia, UWisc

19 Why Resurce Abstractin? Resurce abstractin Mask cmplexity Cver multiple devices Reliability Resurce sharing Efficiency Fairness Prtectin and security 19 Ref. MOS4E, Clumbia, UWisc

20 Hw des an OS wrk? Cmputers have tw mdes f peratin User mde (applicatin) Kernel mde (OS kernel) Transitin between user/kernel mde Interrupt HW device requests OS services (asynchrnus/interrupt-driven) Trap user prgram requests OS services (synchrnus/blcking) Exceptin errr handling 20 Ref. MOS4E, OS@Austin, Clumbia, UWisc

21 Different Types f OS Batch prcessing Prcesses jbs ne by ne Time sharing OS Prcesses multiple jbs in rund rbin Real-time OS Still time-sharing, but has deadlines fr certain jbs Distributed OS Multiple cmputers run a single cpy f OS Embedded OS Runs n cell phnes, PDAs, tailred and highly efficient 21 Ref. MOS4E, OS@Austin, Clumbia, UWisc

22 The Structure f OS Hybrid Kernel UNIX, Linux, Windws 98 Mach Advantage v.s. disadvantage? Windws NT, Mac OS X 22 Ref. MOS4E, OS@Austin, Clumbia, UWisc

The Structure f OS Mnlithic kernel A large prcess running entirely in a single address space (a single binary file) All kernel services execute in kernel address space Prs: fast, easy

23 The Structure f OS Mnlithic kernel A large prcess running entirely in a single address space (a single binary file) All kernel services execute in kernel address space Prs: fast, easy t implement Cns } Huge kernel, harder t maintain } N prtectin between kernel cmpnents } Cmplex dependencies amng cmpnents, nt easily extensible 23 Ref. MOS4E, OS@Austin, Clumbia, UWisc

The Structure f OS Micrkernel Kernel brken dwn t separate prcesses (aka servers) Servers kept separate and run in different address spaces Cmmunicatin is dne via message passing } Servers cmmunicate

24 The Structure f OS Micrkernel Kernel brken dwn t separate prcesses (aka servers) Servers kept separate and run in different address spaces Cmmunicatin is dne via message passing } Servers cmmunicate thrugh IPC (Inter-prcess Cmmunicatin) Prs } Mdular design, easily extensible } Easy t maintain } Mre reliable and secure Cns: Perfrmance lss, cmplicated prcess management 24 Ref. MOS4E, OS@Austin, Clumbia, UWisc

Histry f Operating Systems First generatin 1945-1955 Vacuum tubes, plug bards Transistrs, batch systems ICs and multiprgramming Persnal cmputers: LSI (large scale integratin)

25 Histry f Operating Systems First generatin Vacuum tubes, plug bards Transistrs, batch systems ICs and multiprgramming Persnal cmputers: LSI (large scale integratin) Secnd generatin Third generatin Furth generatin 1980 present Present next 5-10 years Mbile devices Many-cre cmputers 25 Ref. MOS4E, OS@Austin, Clumbia, UWisc

26 Summary An OS is just a special prgram Tw functinalities: resurce abstractin and sharing Prvides services t user prgrams Three ways t request OS services Interrupt, trap, and exceptin Next class Overview f cmputer hardware Organizatin f perating systems 26 Ref. MOS4E, OS@Austin, Clumbia, UWisc

CS5530 Mobile/Wireless Systems Introduction

CS5530 Mobile/Wireless Systems Introduction Mbile/Wireless Systems Intrductin Yanyan Zhuang Department f Cmputer Science http://www.cs.uccs.edu/~yzhuang UC. Clrad Springs Intr f Intr Yanyan Zhuang PhD in netwrk systems yzhuang@uccs.edu Office hurs