...Resource Allocation Graphs Roger Henriksson Department of Computer Science Lund University The possibility of deadlock is an undesired property (to say the least) of safety-critical real-time systems. Therefore, a method to verify that a system cannot deadlock, or to detect possible deadlock situations, is of tremendous value. One such method is resource allocation graphs. As stated in Operating System Concepts by Peterson and Silberschatz [PS85], the occurrence of deadlock requires among other things that hold-wait situations exist and a circular chain of such hold-waits must exist. A resource allocation graph attempts to graphically illustrate all the hold-wait situations in a system. In this graph it is possible to search for cases of circular hold-wait. In their book, Peterson and Silberschatz [PS85] (Section 8.2.2) introduce a method for drawing resource allocation graphs. However, in their version the resource allocation graph shows all the hold-wait-states that exist at any one given point in time. This is a good tool for illustrating a transient state in the system, but in order to use their version of the graphs for detecting any possible deadlock situation we would have to draw a graph for each and every possible combination of execution state for all threads in the system. Then, each and every one of these graphs would have to be analysed for cycles indicating circular wait. This is clearly unpractical. Instead, we modify the method of drawing resource...
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...Special Report Bundle C++Ox: The Dawning of a New Standard Contents C++0x: The Dawning of a New Standard It's been 10 years since the first ISO C++ standard, and 2009 will bring us the second. In this special report, DevX delves into the new features being discussed by the standards team. Learn how these new features will revolutionize the way you code. Overview: C++ Gets an Overhaul It's been 10 years since the first ISO C++ standard, and 2009 will bring us the second. Learn about the new features being added and how they will revolutionize the language. Easier C++: An Introduction to Concepts C++0x concepts bring the full power of the Generic Programming paradigm to C++, making templates more expressive, easier to write, and easier to use. Spectacularly poor template error messages are a thing of the past! Simpler Multithreading in C++0x The new standard will support multithreading, with a new thread library. Find out how this will improve porting code, and reduce the number of APIs and syntaxes you use. The State of the Language: An Interview with Bjarne Stroustrup C++ founding father assesses the language on the eve of its new standard. Timeline: C++ in Retrospect From its nascent pre-processor in 1979 to today's incredibly sophisticated language features and libraries, we've documented each step along the way. C++0x: The Dawning of a New Standard Overview: C++ Gets an Overhaul Overview: C++ Gets an Overhaul C++Ox: The...
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...just one flavor good enough for me, yeah me Don't gimme no crummy taste spoon I know what I need Baby, I love rocky road So weren't you gonna buy half a gallon, baby I love rocky road So have another triple scoop with me, ow They tell me ice cream junkies are all the same All the soda jerkers know my name When their supply is gone Then I'll be movin' on But I'll be back on Monday afternoon, you'll see Another truck load's comin' in for me, all for me I'm singin' I love rocky road So weren't you gonna buy half a gallon, baby I love rocky road So have another triple scoop with me, ow (oh, make it talk) When I'm all alone, I just grab myself a cone And if I get fat and loose my teeth that's fine with me Just lock me in the freezer and throw away the key Singing I love rocky road So weren't you gonna buy half a gallon, baby I love rocky road So have another triple scoop with me I love rocky road So weren't you gonna buy half a gallon, baby I love rocky road So have another triple scoop with I love rocky road So weren't you gonna buy half a gallon, baby I love rocky road So have another triple scoop with I love rocky road So weren't you gonna buy half a gallon, baby I love rocky road So have another triple scoop with...
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...car-jacking was not taken well by either of them but particularly by Jean. The car-jacking revealed racial bias or outright prejudice and lack of trust on Jeans part when a Hispanic locksmith comes to change the locks on their house because they’re car keys would give the car-jacker’s access to their house. Jean tells Rick that she thinks that the lock smith is going to have his gang come back and rob the house. She attributes him being gang affiliated due to his shaved head and multiple tattoos. Rick is passive in this conflict and his resolution is more to calm Jean than to point out her flawed way of thinking, mainly her racial bias towards the locksmith and the fact that the car-jacking was likely an isolated incident in itself. Rick’s failure is to point out to Jean her flawed way of thinking, including her racial bias towards the locksmith. Their being carjacked is scary and life altering event in itself, but it should not create permanent discord and racial tension because the carjackers where minorities. Rick fails to point out Jeans racial bias when she tells him what she thinks that locksmith, Daniel, is going to do. This is made ever more omniscient by the fact that Daniel, can hear Jean voice her fears and racial undertones to Rick while he is working on the locks. Rick’s passiveness is seemingly due to him seeking to consol his wife who has not recovered from being car-jacked and to reassure her that everything is going to be alright. He makes no effort to confront...
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... Is also great And would suffice. HOUSE FEAR by: Robert Frost (1874-1963) LWAYS--I tell you this they learned-- Always at night when they returned To the lonely house from far away To lamps unlighted and fire gone gray, They learned to rattle the lock and key To give whatever might chance to be Warning and time to be off in flight: And preferring the out- to the in-door night, They learned to leave the house-door wide Until they had lit the lamp inside. A LATE WALK by: Robert Frost (1874-1963) HEN I go up through the mowing field, The headless aftermath, Smooth-laid like thatch with the heavy dew, Half closes the garden path. And when I come to the garden ground, The whir of sober birds Up from the tangle of withered weeds Is sadder than any words. A tree beside the wall stands bare, But a leaf that lingered brown, Disturbed, I doubt not, by my thought, Comes softly rattling down. I end not far from my going forth By picking the faded blue Of the last remaining aster flower To carry again to you. THE LOCKLESS DOOR by: Robert Frost (1874-1963) T went many years, But at last came a knock, And I thought of the door With no lock to lock. I blew out the light, I tip-toed the floor, And raised both hands In prayer to the door. But the knock came again My window was wide; I climbed on the sill And descended outside. Back over the sill I bade a “Come in” To whoever...
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...use multiple threads in order to take advantage of hardware parallelism. Java is one of the first languages to make multithreading available to developers. Along with advantages of concurrent systems and multithreading, there are some challenges involved. Java has inter-process communication model which means it has set of methods for exchange of data among multiple threads and processes. It is based on shared data structures and meshes well with hardware architectures in which multiple cores share memory. However Java is susceptible to deadlocks. Deadlock is a condition under which the entire program is halted as each thread in a set attempts to acquire a lock already held by another thread in a set. Java is susceptible to deadlocks because (a) threads exchanges information by sharing variables that they lock with mutex locks and (b) the locking mechanism interacts with other language features, such as aliasing. Consider a simple banking transaction example. [pic] Figure 1: Deadlock scenario in banking transaction .In this case if there are two threads attempting to run transfer(a,b) and transfer(b,a) at the same time then deadlock is going to occur because both threads try to acquire the resources in reverse order. Once a program is deadlocked the source of deadlock is difficult to determine making it difficult to resolve the deadlock....
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...SPECIFIC SITE DUTIES Morning Guard: Commencing around 0250hrs. Rostered hours – 0300hrs to 1130hrs ½ Hour meal at approximately 0830hrs. Off duty 1130hrs after change over and briefing oncoming guard. Unlock and re-lock main gates on entry, unlock gatehouse, sign on in log book and time sheet. Ring mobile night guard let him know you are on site, ring SMC, and let them know you are on site, getting the name of the operator and logging it, disarm alarms in both Warehouse and Administration, (either set of two panels is all that is necessary). Turn all lights on as instructed, commence internal and patrol, unlock side gates and open, unlock manual lock on front sliding doors to reception. (Await Duty Manager to arrive.) When above is completed re-open main gates, (one needs to be secured open with small chain) meet and greet staff (from approximately 0400hrs on) and commence logging trucks, Toll Fast vehicles and couriers etc. Log all casual, contractor and staff, who need access cards in register, remember to issue correct card, ie: warehouse/casual card – admin/staff card/Contractors. All staff, visitor and contractor vehicles are to be searched on leaving the site ie. Boot and wheel well, glove box, consol and behind front seats. Note: This applies to all staff. Random ID checks at least once a week if possible. Bag searches when possible of outgoing staff. NOTE: DEFINATELY NO DELIVERY TRUCKS BEFORE 0700hrs ARE PERMITTED PAST SIDE GATES...
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...pare the processors’ access to printers and other I/O devices for the master/slave and the symmetric multiprocessing configurations. Give a real-life example where the master/slave configuration might be preferred. 2. Compare the processors’ access to main memory for the loosely coupled configuration and the symmetric multiprocessing configurations. Give a real-life example where the symmetric configuration might be preferred. 3. Describe the programmer’s role when implementing explicit parallelism. 4. Describe the programmer’s role when implementing implicit parallelism. 5. What steps does a well-designed multiprocessing system follow when it detects that a processor is failing? What is the central goal of most multiprocessing systems? 6. Give an example from real life of busy waiting. 7. In the last chapter, we discussed deadlocks. Describe in your own words why mutual exclusion is necessary for multiprogramming systems. 8. Compare and contrast multiprocessing and concurrent processing. Describe the role of process synchronization for both systems. 9. Describe the purpose of a buffer and give an example from your own experience where its use clearly benefits system response. 10. Consider this formula: G = (A + C2) * (E1)3 / D + B a. Show the order that a processor would follow to calculate G. To do so, break down the equation into the correct order of operations with one calculation per step. Show the formula for each step. b. Find the value of G: if...
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...Four people are selling tickets at the same time. The number of all tickets is 40. Each ticket only can be sold one time. import java.util.concurrent.locks.ReentrantLock; public class ThreadTest implements Runnable { int tickets = 40; ReentrantLock lock = new ReentrantLock(); public void run() { while (true) { lock.lock(); try { if (tickets > 0) { System.out.println(Thread.currentThread().getName() + "is selling NO."+ tickets + " ticket."); --tickets; } lock.unlock(); } catch (Exception e) { lock.unlock(); } } } } public class Demo1 { public static void main(String[] args) { ThreadTest tt = new ThreadTest(); Thread t1 = new Thread(tt); Thread t2 = new Thread(tt); Thread t3 = new Thread(tt); Thread t4 = new Thread(tt); t1.start(); t2.start(); t3.start(); t4.start(); } } result: Thread-0is Thread-0is Thread-0is Thread-0is Thread-0is Thread-0is Thread-0is Thread-0is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is Thread-3is selling selling selling selling selling selling selling selling selling selling selling selling selling selling selling selling selling selling...
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...of times that other threads are allowed to enter their critical sections, before the request is granted. Concurrent Software Systems 3 Problem Description In discussion of the critical section problem, we often assume that each thread is executing the following code. It is also assumed that (1) after a thread enters a critical section, it will eventually exit the critical section; (2) a thread may terminate in the non-critical section. while (true) { entry section critical section exit section non-critical section } Concurrent Software Systems 4 2 Solution 1 In this solution, lock is a global variable initialized to false. A thread sets lock to true to indicate that it is entering the critical section. boolean lock = false; T0: while (true) { while (lock) { ; } lock = true; critical section lock = false; non-critical section } T1: while (true) { while (lock) {...
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...Name Course Current & Emerging Technology Running a start-up company is a fairly easy task to take with basic business administrative skills. The problem start to arise when the business is showing progress and growth and expansion is imminent. At this juncture of growth, two things unfold for the business. The business earns more profits due to customer base growth, also known as economies of scale and also the business may run into difficulties in the daily running, also known as diseconomy of scale (Ordóñez et al, 2012). In Simple Gateways, growth is finally a reality and hence creeps in this diseconomy of scale. Communication is vital in any organization or company, and as such it is paramount that the communication be flawless. Communication in Simple Gateways is marred by a flawed system; this brings multiple problems to the company in terms of efficiency, accuracy and time management. Key stakeholders are affected negatively by the current inefficient system. Information is not easily disseminated between departments; this greatly hampers the progress of the company and promotes the redundancy in record keeping. Much improvement needs to be done to salvage the situation. Information should be readily available for all the stakeholders on demand. Whether it is between managers or subordinates, there should be a smooth and steady flow of information. There should be an effective system implemented for further future growth and efficiency. The current system...
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...Residential Locksmith, Cypress Residential Locksmith, Cypress has been at the forefront of serving families in Cypress with professional locksmith services year after year, for as long as we can remember. We consider the entire community Cypress as part of our cherished customers, which is why we never fail to ensure our exceptional residential services readily available to them whenever the need arises. As always, we put the community first in everything we do, because we know they expect professionalism and devotion from us. Asides from providing highly economical, low priced and budget friendly locksmith services to the residents of Cypress, other neighboring cities such as Long Beach, Anaheim, La Palma, Stanton and many others also have...
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...TAS #6 Marissa Cooney July 16, 2013 Summary: The colon zone is an area that allows for a ton of money to be brought into Panama. This is a site to hold containers and tons of merchandise with the best designer labels. It has accounted for $10 billion a year to be brought into the country. That is 7.5% of the GDP. The Panama Canal is home to the largest and most important shipping lines in the world. The canal is the cornerstone of the Panama economy. Increasing foreign investments is the goal in order to fuel the growth of the Panama economy. Real estate prices are soaring here and new commercial projects and residential communities are popping up everywhere. There is also 0% employment here because of the land-rush. Panama was recently rated number one to retire in for its quality of life, securities, health services and value for your money. Point of View: This will have much value to both Panama and US companies as imports are accounting for 45% of the Panama income brought in. The Panama Canal is welcoming more and more shipments, increasing sales to both countries. Panama is also expanding their businesses located there encouraging US companies to expand into the territory. This is very good for the US as it will increase sales and provide more income into the US. Panama companies will continue to thrive, and so will the US businesses conducting business with them. Panama is providing many opportunities for advancement, and is attracting many people to move...
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...MGT 565 | Just Cause Assignment | Stephanie Bourdo | 1/29/2013 | Section 1 – Due Process A. Arguments to support Maria was provided due process: * Maria was part of a group that was given a formal verbal warning and reminder of the policy regarding no company property other than protective gear or clothing could be in employee’s lockers. * The verbal warning/reminder ended with a statement indicating that anyone caught violating the rule would be subject to discipline, including the possibility of discharge. * There is a formal policy that is listed in the employee handbook which Maria received upon starting that states “willfully removing or unauthorized possession of property or documents of the Company will constitute just cause for disciplinary action, up to and including discharge.” * Management did not just take Cecelia’s word for the fact that Maria had company property in her locker, they actually checking and confirmed. * Maria was given an opportunity to explain herself regarding the company property in her locker. * Maria was not immediately released; she was suspended without pay while the company did a further investigation. * After the investigation resulted in understanding that company property in lockers was a common occurrence, Maria was given another chance to explain/defend her situation. B. Arguments to support that Maria was NOT provided due process: * Maria may argue that although she was given...
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...this strange at first, it became clear later as to why he used a Gorilla in the first place. The Gorilla here represents nature's voice and is a reminder that we need to look for ways to communicate with nature, first hand. This was the first eye opening aspect from the author. The second was the author's penchant for coming up with brilliant stories to derive and communicate his point to the reader. Instead of driving in his philosophies by pure theory would have been boring and heavy, but the author uses wonderful and thought provoking stories to do the same, so effectively. The first was the simple concept of food kept under lock and key. This is a practice that comes so naturally to us, but he brings out why this is a very unnatural way of things. For early man, what grew in the world belonged to everyone in the society, and to put it under lock and key is to basically create a working class who will do tasks, useful or useless, in order to earn their bread. Ishmael's (the name of the gorilla) teachings turn toward the subject of formal education, which he argues is merely a way to keep children out of the work force and is otherwise unnecessary because humans learn on their own, naturally following their own interests and picking up information necessary to operate in their culture. In tribal cultures, this information inherently includes that which is relevant to surviving in the wild by learning to hunt and gather food, as well as easily adopting their culture's values...
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