Download Operating Systems Welcome Emotional Help and more Lecture notes Computer Networks in PDF only on Docsity!
Operating Systems
Spring 2021
Lorenzo Alvisi & Robbert van Renesse
CS 4410
[Alvisi, Bracy, Schneider, Sirer, van Renesse]
Welcome
We strive to make CS4410/CS4411 welcoming, safe, equitable, and respectful environments, consistent with Cornell’s commitments
We recognize that the society with live in is none of those things, that we have implicit biases, and that we have to work hard every day to counter those biases to create an inclusive environment
If you witness a bias incident or have been the victim of one, please file a confidential report with Cornell
If you have any suggestions (improvements to the web site, syllabi, slides etc) feel free to eamil us at cs4410- prof@cornell.edu
Emotional Help
Engineering Advising www.engineering.cornell.ed u/resources/advising^ Academic advising forengineering students
Arts College Student as.cornell.edu/advising
Listing of general support services for a variety of concenrs Gannett www.health.cornell.edu Cornell University HealthService
CAPS health.cornell.edu/services/ mental-health-care
If you experience emotional stress, contact Counseling and Psychological services
Student Disability Services sds.cornell.edu
Ensures that all aspects of student life are accessible, equitable, and inclusive of those with disabilities. Send accommodation letters to Ms. Coralia Torres (ct635), by Feb. 23.
Get help. Get documentation. The earlier, the better And look out for each other!
Who is Who
Before you take this class..
Communication
Lectures, OHs, FAQ, etc.
Getting help
Homework, exams
Grades & Policies
About RvR
Ph.D. C.S., Vrije Universiteit Amsterdam Amoeba Distributed Operating System
Industry: Research Scientist @ AT&T Bell Labs Unix, Plan 9
Serial entrepreneur Reliable Network Solutions (IP -> Amazon) D.A.G. Labs (acquired by FAST, then by Microsoft) Exotanium (ongoing)
Interests: scalable and fault tolerant distributed systems
Non geek: musician (trad. jazz) swing dance, unicycling
About Lorenzo
Ph.D. C.S., Cornell University Fault-tolerant distributed computing Physics MS from University of Bologna
UT Austin: 1996- Academy of Distinguished Teachers
Serial: Consumer of dark chocolate Motorcycle owner (4 currently)
Interests: scalable and fault tolerant distributed systems
Non geek: classical music, literature, hiking, riding
Who are the TAs?
Michael Chin CS B. Sc. he, him, his
Jack Ding CS B. Sc he, him, his
Ziwei Gu CS M.Eng. he, him, his
Mindy Lee CS M.Eng. she, her, hers
Minghao Li CS B. Sc. she, her, hers
Simon Huang CS B. Sc. he, him, his
Kartikay Jain CS B. Sc. he, him, his
Youer Pu CS Ph.D. she, her, hers
Freya Ryd CS B. Sc. she, her, hers
Nikhil Saggi CS M.Eng. he, him, his Haocheng Shen CS B. Sc. he, him, his
Xinwen Wang CS Ph.D. he, him, his
Nicholas Zahabiun CS M.Eng. he, him, his Jiejun Zhang CS M.Eng she, her, hers
Yu-Ju Huang CS Ph.D. he, him, his Yunhao Zhang CS Ph.D. he, him, his
Communication
Lectures, OHs, FAQ, etc.
Getting help
Homework, Exams
Grades and Policies
Who is who
Before you take this class..
Free online
Linked from CS4410 web
site
/ new typo
/ new program
bug
Textbooks
Concurrent
Programming
with Harmony
Robbert van Renesse
Cornell University
Communication
Lectures, OHs, FAQ, etc.
Getting help
Who is who
Before you take this class..
Homework, Exams
Grades and Policies
Communications
Largely virtual
need for more communication!
Web page
Lectures
FAQ
Office Hours
Study Groups
CMS
Course Web Page
Schedule, exam & due dates
Homework release and due dates
Slides posted before each lecture
Evolving
FAQ & CMSX
FAQ: sites.coecis.cornell.edu/cs4410faq/
Linked from course web page You can post questions here and find answers at some later time
CMSX: https://cmsx.cs.cornell.edu
Assignments Grades & Regrades
Lectures
Tues/Thurs 1:00-2:15 pm live from Bailey Hall
and on Zoom.
Lectures will be recorded, but attendance in person or on line is expected
Office Hours
There are 210 20 minute slots each week
All days of the week (but Sunday), including evenings Slots posted on line
All OHs are over Zoom
We’ll consider special requests for in-person meetings
You have to register for a slot
Please specify NetID and include topic
Email
cs4410-staff@cornell.edu: time sensitive matters
Goes to profs and TAs
cs4410-prof@cornell.edu: sensitive matters
Goes to Robbert and Lorenzo only
Please no email to personal email accounts
Study Group
Code of Conduct
Each student should feel safe, welcome,
respected
Participate, but don’t dominate
Be patient
Respect diverse talents and ways of learning
Fight your implicit biases
Find Study
Partners!
Studying with peers is a great way to connect with other Cornell students and is a powerful tool for learning. Cornell’s Learning Strategies Center (LSC) helps match you with study partners. To learn more, visit the LSC’s Studying Together webpage or scan the code à
Scan the QR code to find out more about Study Partners or visit http:// lsc.cornell.edu/ studying-together/
lsc.cornell.edu
Find Project
Partners!
Taking a CS class? Looking for a friend? Searching for apartner? If so, this CIS Partner Finding Social is for you!
This is a virtual event where you’ll have the chance tomeet and interact with other students in your CS classes! This is the PERFECT opportunity to find a partner, socome join us on 2/ from 7:30 ~ 9:00pm if you’re taking CS1000~2000 level classes, from 9:00pm ~ 10:30pm if you’re taking 3000+level classes!
RSVP here:
http://bit.ly/cisSP
Academic Integrity
and Honor Code
OK to discuss concepts with any other student Student in a study group can submit the same code Different study groups are not allowed to share code
Violations will be prosecuted
All submitted work must be your own
Exams
Randomized, fillable PDFs
Same as homework Exam questions are versions of homework questions Include questions about lectures, homework, books
Must be done individually
Open-book Internet as “read-only” resource: don’t ask questions
Cumulative
Exams
Timed
2 hours from download to submission Can be done any time in 48-hour period
3% penalty each 15 minutes late, up to 1 hour
Fully auto-graded
Regrade requests due within one week
Communication
Lectures, OHs, FAQ, etc.
Getting help
Who is who
Before you take this class..
Homework, Exams
Grades and Policies
Semester Grades
50% Assignments
50% exams
No curving
CS4410 is not a competition Your grade reflects your learning objectives not how well you compared with others
Weighing of individual assignments and
exams TBD
What is a system?
“A complex unit formed of many often diverse parts subject to a common plan or serving a common purpose” Webster Third New International Dictionary
What is a system?
“A complex unit formed of many often diverse parts subject to a common plan or serving a common purpose” Webster Third New International Dictionary
components
interconnections
a certain behavior at the interface with an environment
“A set of interconnected components with an expected behavior observed at the interface with its environment”
Common systems
challenges
Emergent properties
Propagation of effects
Incommensurate scaling
Trade-offs
Emergent Properties
Evident only when components are combined
Millenium Bridge
London
Propagation of effects:
fighting malaria
WHO sprayed villages in N. Borneo with DDT
Wiped out mosquitos, but…
Roaches collected DDT in tissue
Lizard ate roaches, and became slower
Easy target for cats
DDT cause cats to die
Forest rats moved into villages
Rats carried the bacillus of the plague!
Incommensurate scaling
As the system increases in size or speed, not all components can manage the scale, and things break down
10x higher than Jack! but also 10x wider and thicker! About 1000x Jack’s weight — but the cross section of the Giant’s bones was only 100x Jack’s A human thigh bone breaks at about 10x human weight The giant would have broken his thighs every time he was taking a step! On being the right size J.B.S. Haldane
Inevitable Trade-offs
Speed vs power in processors
Bandwidth vs computation in compression
Space vs time almost everywhere
A pawn vs better position in chess
How to Manage
Complexity
Modularity
Good modularity minimizes connections between components
Abstraction
Separate interface from internals; separate specification from implementation
Hierarchy/Layering
Constrain interactions so they are easier to understand
User Programs
User
Operator Console Memory Management
I/O Management
CPU Scheduling and Semaphores Hardware
5 (not implemented)
EWD 196, 1965
THE Operating system
OS as Illusionist
Virtualization
Processor, memory, screen space, disk, network The entire computer Fooling the OS itself! Eases debugging, portability, isolation
Appearance of resources not physically present
Operating System
Application Application Application Application Application
Hardware
VM Interface
VMM
Application Application Application Application Application
Hardware
Guest OS 1 Guest OS 2
VM Interface VM Interface
Appearance of resources not physically present
Atomic operations
HW guarantees atomicity at the word level… What happens during concurrent updates to complex data structures? What is a computer crashes while writing a file block? At the hardware level, packets are lost Reliable communication channels
OS as Illusionist
OS as Glue
Offers standard services to simplify app design
and facilitate sharing
Send/Receive byte streams Read/Write files Pass messages Share memory UI
Decouples HW and app development
What will the
course be like?
Harmony
Your Automated Concurrency Tutor
