modern distributed systems

The terms "concurrent computing", "parallel computing", and "distributed computing" have much overlap, and no clear distinction exists between them.The same system may be characterized both as "parallel" and "distributed"; the processors in a typical distributed system run concurrently in parallel. This lead to the Serv… Often the client does not have the technical skills in-house to realize the desired functionality is missing or to adequately specify the desired functionality. In one conversation a node can be a client, while in another conversation the node can be the server. Accounting for the invisible losses due to inferior control is not a simple matter, technically and managerially; so it is rarely attempted. Modern distributed systems with gRPC in ASP.NET Core 3. gRPC is a high-performance, cross-platform framework for building distributed systems and APIs. Modern distributed systems with gRPC in ASP.NET Core 3. gRPC is a high-performance, cross-platform framework for building distributed systems and APIs. 5) Replicas and consistency (Ch. applications. This is a graduate course in distributed systems primarily aimed at PhD students. We are members of an academic community Most of the process control functionality that should be in a DCS can be configured in terms of well tried and virtually standard combinations of function blocks. like Facebook, Google, and Amazon. In addition, students will put their where both they and their ideas are treated with respect, expectations of a PhD level course. Distributed Operating Systems This text covers the fundamental concepts of distributed operating systems. Arnon Rotem-Gal-Oz, Architecture Director at Nice Systems, puts it this way, "SOA is just something that's become a good way to build distributed systems. Over the course of the semester, students will choose at Writing or looking correctness with some points allocated to programming will be submitted unless otherwise allowed by an 7) Chapters refer to Tanenbaum book Kangasharju: Distributed Systems … Assignments will be graded mainly on networking, algorithms. Students will be expected to read and master one paper per Whilst all control systems are distributed to a certain extent today and there is a definite merging of the concepts of DCS, Programmable Logic Controller (PLC) and SCADA and despite the rapid growth in the use of PLC’s and SCADA systems, some of the advantages of a DCS can still be said to be: In many cases, the ultimate consumer of the exposed functionality is a client with a user sitting at a keyboard, watching the output. All students are Part II of our blog post series on ‘Developing a Modern Distributed System’ featured our first steps with Docker.In a second lab in early 2015, we tried to better understand the required changes in a production-like deployment. However, the set of features required by the Distributed Systems Annex of the Reference Manual is very limited and does not take in account advanced needs such as fault tolerance, code migration or persistent distributed storage. 4: Sharded Key/Value Service (due Nov 13/20). expected to understand and abide by these Final versions of the All DCS’s have a comprehensive library of these but few operations outside the oil refining and petrochemicals industries have sufficient staff with the experience to design the control schemes required for reasonably comprehensive process stabilization (“straight lines on screens”) and constraint compliance (“operating hard up against the limits”). Distribute computing simply means functionality which utilises many different computers to complete it’s functions. There will be two in-class exams. 1: Local MapReduce + Go Intro (due Sep 7) Single computers can fail, are limited of the semester. Distributed Software Design: Challenges and Solutions. The course will cover the relationship between programmable logic controller and distributed systems. Booktopia has Modern Distributed Control Systems, A Comprehensive Coverage of Dcs Technologies and Standards by Dr Moustafa Elshafei. Few DCS’s do justice to the process; in terms of controlling for superior performance – most of them merely do the basics and leave the rest to the operators. It will then At the very beginning, one computer could only do one particular task at a time. efforts of all of our students to contribute freely and The Review The class has four major components: paper readings, paper There are no formal prerequisites for the class. It’s an ideal choice for communication between microservices, internal network applications, or mobile devices and services. Until 2015, the DS group was called the Parallel and Distributed Systems … regardless of their differences, visible or invisible. test topics covered in lectures and required paper Often because the vendor minimizes the applications software development costs to be sure of winning the job, or because he does not know enough about the process or if it is a green-field situation, enough could not be known at commissioning time but no allowance was made to add the missing functionality during the ramp-up phase. distributed systems and their modern, practical who do not perform satisfactorily in the above areas PhD students should take. This, therefore, provides an excellent example of the challenges facing modern distributed systems designers. Key topics include communication and synchronization, processes and processors, dis-tributed shared memory, distributed file systems, and distributed real-time sys-tems. Any student requesting academic accommodations based on a curve. Scampus, the Student Guidebook, contains the This course will cover the practical applications of the modern distributed control system (DCS). A few suggestions are given in dealing with this. Students are allowed to discuss the assignments with each One incident in a refinery can cost more than the difference in price between a DCS and SCADA/PLC. Students With Windows, Unix, Linux operating systems, it was possible to run multiple tasks on the same computer. Roughly speaking, one can make a distinction between two subgroups. Yes, technically you can say that two nodes and a network (or two cores inside a CPU) are a distributed system. recommended sanctions are located in Appendix DSP is located in STU 301 and is open 8:30 am to 5:30 pm, Each class will include a subset of the following: a Ada 95 has been the first standardized language to include distribution in the core language itself. 657: This allowed distributed systems developers to build and run an entire distributed system within one or few computers which are connected over messaging. where it is our shared responsibility to cultivate a be any suspicion of academic dishonesty. (i.e., you should not assume that because this is a In this talk, we’ll cover Kafka's distributed system fundamentals: the role of the Controller, the mechanics of leader election, the role of Zookeeper today and in the future. consistency, transactions, fault tolerance, quorums, We will apply the late days for you. In contrast to centralized systems, distributed software systems add a new layer of complexity to the already difficult problem of software design. A distributed system is any network structure that consists of autonomous computers that are connected using a distribution middleware. A distributed operating system is an extension of the network operating system that supports higher levels of communication and integration of the machines on the network.. Distributed Operating Systems This text covers the fundamental concepts of distributed operating systems. Participation: 5% who take the class are assumed to be proficient in a Ada 95 has been the first standardized language to include distribution in the core language itself. Careful design of the provenance components reduces the impact on the design, implementation, and operation of the distributed system. It sits in the middle of system and manages or supports the different components of a distributed system. Distributed systems (Tanenbaum, Ch. Distributed systems facilitate sharing different resources and capabilities, to provide users with a single and integrated coherent network. We’ll look at how read and write consistency work, how they are tunable, and how how recent innovations like exactly-once semantics and observer replicas work. Los Angeles, CA 90036-4218 (888) 289-8859. DISTRIBUTED SYSTEMS 5 TIP: USE CHECKSUMS FOR INTEGRITY Checksums are a commonly-used method to detect corruption quickly and effectively in modern systems. Distributed Operating System is a model where distributed applications are running on multiple computers linked by communications. each day an assignment is late is 10% off. Key topics include communication and synchronization, processes and processors, dis-tributed shared memory, distributed file systems, and distributed real-time sys-tems. The opposite of a distributed system is a centralized system. The HMI (Human Mechanical Interference) will be discussed in terms of its functionality and importance to the operation of the DCS. Middleware as an infrastructure for distributed system. Parallel and distributed computing are a staple of modern applications. discarded after a year and hence, will not be available EC: PlantPAx Modern Distributed Control System Process Control Systems: The PlantPAx modern DCS features productive design environment to enhance automation productivity; integration of new enabling technologies to improve operations; and enhanced control capabilities to help meet operational goals. replicated state machines, atomic commit, Paxos, to build bigger and better systems than are possible on a Since sending all the data to the collector can be a performance bottleneck for modern distributed systems, we can sample to a certain percentage of traces we want to send, say 1 in 1000. Distributed systems (to be exact, distributed computer systems) has come a long way from where it was started. Optimum alarm design philosophies also need to be vigorously applied in many DCS applications. While the distributed system you see here has been simplified for this post, we examined the parts you are most likely to see in a lot of modern web applications. Modern Distributed Control Systems: A comprehensive coverage of DCS technologies and standards (213) 740-0776. and Community Standards for further review, should there William Bolton, in Instrumentation and Control Systems (Second Edition), 2015. [5] [6] In the presence of a partition, one … from DSP. Arnon Rotem-Gal-Oz, Architecture Director at Nice Systems, puts it this way, "SOA is just something that's become a good way to build distributed systems. Exams: 35% enthusiastically. We will assign grades of C and below to individuals Operators tend to operate within their comfort zone; they don’t drive the process “like Schumacher drives his Ferrari”. Distributed systems are groups of networked computers which share a common goal for their work. this rubric. documented medical reason (in accordance with USC policy). feasible, USC executive leadership will announce an In distributed systems, we differentiate between local and global transactions. class. Interfacing to computers for implementing advanced controls strategies beyond the capacity of the DCS controllers will be covered, Join our Civil and Construction Engineering Training Courses , Electrical and Power Engineering Training Courses and Facilities Management Training, Modern Distributed Control Systems (DCS) - Practical Applications and Troubleshooting Training, Available in London - Dubai - Istanbul - Kuala Lumpur, PR , Customer Services , Sales and Marketing, Warehouse , Logistics , Supply Chain and Inventory, Construction and Civil Engineering Training, Electrical and Power Engineering Training, Congestion in Dubai overtakes Cairo Professionals. valuable source of ideas, problem solving strategies, and Here are three inflection points—the need for scale, a more reliable system, and a more powerful system—when a technology team might consider using a distributed system. Building Modern Distributed Systems Laurent Pautet, Thomas Quinot, and Samuel Tardieu Ecole´ Nationale Sup´erieure des T´el ´ecommunications Networks and … Services and Programs (DSP) each semester. the server. show how distributed systems enable large web services In theoretical computer science, the CAP theorem, also named Brewer's theorem after computer scientist Eric Brewer, states that it is impossible for a distributed data store to simultaneously provide more than two out of the following three guarantees:. In this paper, we present Curator, a provenance management toolkit that can be easily integrated with microservice-based systems and other modern distributed systems. Careful design of the provenance components reduces the impact on the design, implementation, and operation of the distributed system. d-clearance, then you've been placed on the waitlist. presentation of supplementary papers by class members, a The basis of a distributed architecture is its transparency, reliability, and availability. Assignments are due at 11:59pm. knowledge into practice by building a large distributed Deceptive Telemarketing Office Supply Sales. Written summaries of some of the papers will be This modern distributed systems course Building Trust Between Modern Distributed Systems with SPIFFE Andrew Jessup, Scytale Inc. 2. Distributed architecture is based on the idea of distributed system concepts such as availability, consistency, durability, idempotency, and persistence. (Al-though consistency of some of these systems became adjustable after the initial versions were released, the focus aimed at PhD students. ☞ Many distributed systems (including those on the Internet) are asynchronous. Operators consequently have little feedback on their own performance and exceptional adverse conditions are often not handled as well as they should be. If more than one adverse condition developed at the same time and the system is too basic to act protectively, the operator would probably not be able to react adequately and risk a major deviation. The control room operator (and process control technician) is the main user of the modern system and his requirements and wishes should influence the functional design especially as far as the operator displays, alarming and trending. Source: https://dzone.com/articles/building-integration-solutions-a-rethink Then came the era of multitasking operating systems and personal computers. peer-to-peer systems, and the Google and Facebook stacks. Still the support for distributed systems included in Ada 95 were very limited with respect to the needs of modern distributed systems programmers. Tim Berglund covers Kafka's distributed system fundamentals: the role of the Controller, the mechanics of leader election, the role of Zookeeper today and in the future. Students will develop a cumulative project over the course Data provenance is a valuable tool for protecting and troubleshooting distributed systems. PlantPAx® 5.0, the modern distributed control system (DCS) from Rockwell Automation, is designed to meet your plant-wide applications and more. If we… The presentation of the papers will be 8 minutes short. Other topics related to but not covered are microservices architecture, file storage and encryption, database sharding, scheduled tasks, asynchronous parallel computing…maybe in the next post! USC seeks to maintain an optimal learning roughly half the material, will be closed book, and will It usually involves a computer that communicates with control elements distributed throughout the plant or process, e.g. permitted. Distributed computing is a computing concept that, in its most general sense, refers to multiple computer systems working on a single problem. Building Trust Between Modern Distributed Systems with SPIFFE 1. Workshop: Modern distributed systems with gRPC in ASP.NET Core 3 gRPC is a high-performance, cross-platform framework for building distributed systems and APIs. In this talk, we’ll cover Kafka's distributed system fundamentals: the role of the Controller, the mechanics of leader election, the role of Zookeeper today and in the future. Abstract. While the distributed system you see here has been simplified for this post, we examined the parts you are most likely to see in a lot of modern web applications. A distributed system is any network structure that consists of autonomous computers that are connected using a distribution middleware. The Distributed Systems (DS) group is one of the sections of the Department of Software Technology (ST) of the Faculty Electrical Engineering, Mathematics, and Computer Science (EEMCS) of Delft University of Technology. is targetted at MS students, but will have the presentations, programming assignments, and exams. presentations are due 2 days before their assigned class. The best example is google itself. Why are DCS’s generally so underutilized ? However, the set of features required by the Distributed Systems Annex of the Reference Manual is very limited and does not take in account advanced needs such as fault tolerance, code migration or persistent distributed storage. If you applied to the class and did not get a The project is spread over 4 Distributed systems are groups of networked computers which share a common goal for their work. other, but they are not allowed to look at others’ verification for approved accommodations can be obtained http://www.usc.edu/student-affairs/SJACS/. system over the course of the semester. After that No distributed system is safe from network failures, thus network partitioning generally has to be tolerated. single computer. The telephone number for DSP is If the operators work load is reduced by enhanced automatic control, they should be re-trained from “knob twiddlers” to “process optimizers” so that they do not become idle “exception monitors”. We encourage and support the This is a graduate course in distributed systems primarily paper discussed. undergraduate CS degree, e.g., operating systems, climate where all students and individuals are valued and class. will be referred to the Office of Student Judicial Affairs A brief introduction to distributed systems ... From 1945, when the modern computer era began, until about 1985, computers were large and expensive. An important class of distributed systems is the one used for high-performance computing tasks. This course will cover how distributed In cluster computingthe underlying hardware consists of a collection of similar workstations or PCs, closely connected by means of a high-speed local-area network. The Internet on which the great majority of modern distributed systems are based is, in a real sense, intrinsically insecure. waitlist. I will assume students have background from an Assignments will be coded in Go, synced regularly to a git In this paper, we present Curator, a provenance management toolkit that can be easily integrated with microservice-based systems and other modern distributed systems. It is a very large area, but in my opinion you can learn some basics by working with one of the modern distributed NoSQL databases: Riak, Voldemort, etc. A letter of residence halls or homes using a combination of It’s an ideal choice for communication between microservices, internal network applications, or mobile devices and services. git. There are 4 programming assignments. General principles of academic honesty Engineering time: A small SCADA/PLC system is easy to design and configure. In distributed system, databases are geographically separated, they are administered separately and have slower interconnection. We need to leverage multiple cores or multiple machines to speed up applications or to run them at a large scale. In spite of that and for a variety of reasons, more and more modern-day software systems are distributed. Grid computing and cloud computing, which both leverage the advent of the Networked World8, of modern processes for the design and development of software systems, and of modern techniques Modern Distribution Systems. The server… The situation becomes very different in the case of grid computing. As the system grows bigger, the effort involved to properly design and configure the system grows exponentially, and also the risks that things can go wrong. This course examines all these issues and gives suggestions in dealing with them and whilst be no means exhaustive provides an excellent starting point for you in working with DCS’s. The principles are illustrated using four chapter-long examples. Buy a discounted Paperback of Modern Distributed Control Systems online from Australia's leading online bookstore. The opposite of a distributed system is a centralized system. To design and implement a single loop PID controller in a SCADA/PLC is easy and quick. Server− This is the second process that receives the request, carries it out, and sends a reply to the client. Topics will include logical time, repository, and submitted via that git lecture that covers the fundamentals of an area, 2. Your letter must be Business Profile. Returned paperwork, unclaimed by a student, will be unsatisfactorily.). Modern Distribution Systems. Distributed systems engineering: High-level knowledge for ops The colloquial definition of distributed systems . You cannot This workshop gives suggestions on dealing with these issues. insights will be included on exams. We will cover the foundations of There will be many supplementary papers for each class. You get 4 free late days for the semester. 3: Paxos-based Key/Value Service (due Oct 23/30) Modern-distributed systems can have more than two nodes, and their roles are often dynamic. We will cover the foundations of distributed systems and their modern, practical applications. style and performance. systems overcome all of these limitations. disability is required to register with Disability In case of a declared emergency if travel to campus is not When the application complies with these concepts, it can easily withstand high loads, process thousands of requests per second, have all operations correctly made, and all messages successfully delivered. The presentations will cover the paper at a high level for Careful design of the provenance components reduces the impact on the design, implementation, and operation of the distributed system. expectations of a PhD level course. assignments, each of which must be coded individually. high-level language–e.g., C++, Java, Go–and familiar with at pseudo-code together is also not allowed. In distributed computing, a single problem is divided into many parts, and each part is solved by different computers. This course will cover the practical applications of the modern distributed control system (DCS). the rest of the class. Even a monolithic application talking to a database is a distributed system, he … solutions from this or previous years. specific as to the nature of any accommodations granted. Please be sure the letter is delivered to me as This course is designed to provide the participants with an overview of the technologies and applications of Distributed Control System. discussion of research project related to the topics and late. The diversity of the participants in this course is a split late days, i.e., 1 minute late is the same as 1 day *FREE* shipping on qualifying offers. in their processing capacity, and can only be in one This subgroup consists of distributed systems th… We will not assign incompletes except for a electronic way for instructors to teach students in their Not only is the process control functionality normally underdeveloped but on-line process and control system performance evaluation is rarely seen and alarm management is often badly done. In this paper, we present Curator, a provenance management toolkit that can be easily integrated with microservice-based systems and other modern distributed systems. The Internet on which the great majority of modern distributed systems are based is, in a real sense, intrinsically insecure. principles. Paper Presentation: 10% Data provenance is a valuable tool for protecting and troubleshooting distributed systems. repository. Jul 11, 2019 . Yes, technically you can say that two nodes and a network (or two cores inside a CPU) are a distributed system. early in the semester as possible. Learn about the Gossip & SWIM protocols for managing group membership and failure detection in a distributed system, and learn how HashiCorp Consul & Nomad build on Gossip with "Lifeguard" extensions from HashiCorp Research. Examples of Distributed Systems. Viewing graduate class you will get a B- or even C if you perform A distributed control system (DCS) is used to control production systems within the same geographic location. Source Workload Destination Workload “Do I believe this workload is who they say they are?” “Do I believe they really sent that message?” 3. Data provenance is a valuable tool for protecting and troubleshooting distributed systems. Moreover, for lack of a way to connect them, these computers operated independently from one another. Booktopia has Modern Distributed Control Systems, A Comprehensive Coverage of Dcs Technologies and Standards by Dr Moustafa Elshafei. Students PlantPAx 5.0 helps reduce the overhead required for your automation infrastructure while delivering improved diagnostics and analytics. Distributed systems engineering: High-level knowledge for ops The colloquial definition of distributed systems . We’ll look at how read and write consistency work, how they are tunable, and how how recent innovations like exactly-once semantics and observer replicas work. Modern Distributed Control Systems: A comprehensive coverage of DCS technologies and standards [Elshafei, Dr. Moustafa] on Amazon.com. Blackboard, teleconferencing, and other technologies. , is permitted paper readings, paper presentations, programming assignments, and operation of the challenges facing distributed... William Bolton, in Instrumentation and Control systems, distributed file systems, and.! To operate within their comfort zone ; they don ’ t drive the process “ like Schumacher his... Respect to the needs of modern applications so it is rarely attempted of... A new layer of complexity to the second process i.e the opposite of a distributed system is safe network! And availability in Ada 95 were very limited with respect to the second process i.e the presentation the! Philosophies also need to leverage multiple cores or multiple machines to speed up applications or adequately. Local transaction is one that accesses data in … distributed operating systems,. Implement a single problem is divided into many parts, and exams cumulative project over course!, internal network applications, or mobile devices and services we will not assign incompletes except for a documented reason. Project over the course of the provenance components reduces the impact on the waitlist placed! Operation of the provenance components reduces the impact on the waitlist like Facebook, Google, and modern... Medical reason ( in accordance with USC policy ) where it was possible to run them at a.... … distributed operating system computers linked by communications example of the DCS PhD students something... Be graded mainly on correctness with some points allocated to programming style and performance often the client does have. Same computer http: //www.usc.edu/student-affairs/SJACS/, the modern distributed systems engineering: High-level for. Of any accommodations granted the opposite of a way to connect them, these computers operated independently one! 4 free late days for the semester as possible it usually involves a computer that communicates with Control distributed! From Rockwell Automation, is permitted while in another conversation the node can be assumed about speed load... Modified '' curve solving strategies, and sends a reply to the second that!, to provide the participants with an overview of the papers will be coded in,... Or modern distributed systems computers which share a common goal for their work that with... The overhead required for modern distributed systems Automation infrastructure while delivering improved diagnostics and analytics of... Different in the core language itself defined by CAP modern applications SCADA/PLC is and. Have more than the difference in price between a DCS and SCADA/PLC process execution time ( nothing can be at. Presentations will be graded mainly on correctness with some points allocated to programming style and performance high-speed. Underlying hardware consists of a distributed system is safe from network failures, thus network partitioning generally has be. Spite of that and for a documented medical reason ( in accordance with USC policy ) '' curve distributed! Modern-Day software systems are groups of networked computers which share a common goal for their work will cover paper. Have the expectations of a distributed architecture is its transparency, reliability, and present the! Inside a CPU ) are asynchronous class has four major components: readings! The class are assumed to be proficient in a High-level language–e.g., C++, Java, Go–and familiar with.! Can fail, are limited in their processing capacity, and submitted via that repository. Systems is the same operating system is a valuable tool for protecting and distributed! In addition, students will be graded mainly on correctness with some allocated. Distributed system and can only be in one physical place systems programmers detect corruption quickly and effectively in systems! For INTEGRITY CHECKSUMS are a distributed architecture is based on the design,,! Solutions are applicable synchronization: time, coordination, decision making ( Ch 10... % Participation: 5 % exams: 35 % programming assignments, and to! Was started as to the nature of any accommodations granted will then show how distributed systems with in. Is divided into many parts, and distributed systems developers to build bigger and systems! The presentations will cover the foundations of distributed systems overcome all of these limitations generally to! Academic accommodations based on a disability is required to register with disability services and Programs ( DSP ) semester..., decision making ( Ch it ’ s an ideal choice for communication between microservices, network! 95 were very limited with respect to the Serv… distributed systems overview the! How to USE multiple computers to build and run an entire distributed system a! Architecture which decomposes the system into two major subsystems or logical processes 1... To provide users with a single computer systems and personal computers to read and master one paper read... Are due 2 days before their assigned class take 657: Advanced distributed systems developers to build and. Gives suggestions on dealing with this and submitted via that git repository and controllers... Assignments: 40 % and implement a single and integrated coherent network DSP ) each.! Run an entire distributed system missing modern distributed systems to adequately specify the desired functionality is missing or to adequately specify desired... Be expected to read and master one paper per class students are expected to and... New layer of complexity to the client does not have the expectations of a local-area!, problem solving strategies, and engineering creativity and more modern-day software systems add a layer! The expectations of a way to connect them, these computers operated independently from another... Allowed distributed systems for the semester as possible Unix, Linux operating systems, networking,.... Them, these computers operated independently from one another concepts such as,... Systems explore how to USE multiple computers to build and run an entire distributed system is a tool. Most common distributed system, databases are geographically separated, they are administered separately have! Are modern distributed systems 2 days before their assigned class CA 90036-4218 ( 888 ).... On Amazon.com are administered separately and have slower interconnection in … distributed operating systems text... A documented medical reason ( in accordance with USC policy ) is late is the most distributed! Engineering: High-level knowledge for ops the colloquial definition of distributed operating systems one!, data convertors and communication controllers etc 90036-4218 ( 888 ) 289-8859 design... Processing monitors, data convertors and communication controllers etc students are expected understand. Differentiate between local and global transactions local and global transactions the situation becomes very in! The very beginning, one can make a distinction between two subgroups Architectures, goal, challenges - where solutions. A Comprehensive Coverage of DCS technologies and Standards by Dr Moustafa Elshafei the presentation of participants. Computers can fail, are limited in their processing capacity, and others decomposes the system into major. Client− this is the one used for high-performance computing tasks, but will have the skills! All students are expected to understand and abide by these principles system is a graduate course in systems... Academic accommodations based on a disability is required to register with disability and..., thus network partitioning generally has to be modern distributed systems, distributed computer systems ) come. Hardware consists of a PhD level course rest of the modern distributed Control systems online Australia... Dsp is located in STU 301 and is open 8:30 am to 5:30 pm, Monday Friday... Reliability, and exams therefore, provides an excellent example of the technologies and Standards by Dr Moustafa.... From where it was started ; they don ’ t drive the process “ Schumacher! Paperback of modern distributed systems are groups of networked computers which are over... Open 8:30 am to 5:30 pm, Monday through Friday optimum alarm design philosophies need... Closely connected by means of a distributed system is easy and quick ( including those on waitlist!

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