Question:
In your own words, describe how binary semaphores and mutexes are implemented in FreeRTOS. (Do not include counting semaphores.) In the discussion go to the level of the FreeRTOS code relevant to semaphores (i.e. your description should include code snippets from the FreeRTOS semaphore code). Be sure to cover all relevant aspects of priority-related issues and how the code supports the context switching mechanism (without going into the code-level details of how the context switching mechanism is implemented). Include a section that relates your FreeRTOS description to content from SYSC 5701 lectures.
Solution:
Semaphore is a Greek word where sema means “sign or signal” and phore means “carrier” and is said to be used as a protected variable. There are basically four types of semaphores:
1. Binary Semaphores
2. Counting Semaphores
3. Mutex
4. Recursive Mutex
In FreeRTOS, the concept of semaphore has different meaning based on the context and also its level of usage. FreeRTOS implements semaphores as to synchronize the set of tasks with the other events in system and they are implemented based on the queue mechanism.
A macro that is being defined is responsible for creating a semaphore using the standing queuing mechanism. This queue length can be either 0 or 1 based on the type and context of the semaphore being used.
The concept of Binary Semaphore and Mutex are considered to be the two different levels of implementation of the Semaphores or may be considered as two different use cases viz. Mutual Exclusion and Signaling. There, the confusion still exists on the usage and the terminology of the Mutex and Semaphores. As said, the semaphore can take different meaning based on the context level and ...
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... vSemaphoreCreateBinary( xSemaphore );
if( xSemaphore != NULL )
{
if( xSemaphoreGive( xSemaphore ) != pdTRUE )
{
// We would expect this call to fail because we cannot give
// a semaphore without first "taking" it!
}
// Obtain the semaphore - don't block if the semaphore is not
// immediately available. if( xSemaphoreTake( xSemaphore, ( portTickType ) 0 ) )
{
// We now have the semaphore and can access the shared resource.
// ...
// We have finished accessing the shared resource so can free the semaphore. if( xSemaphoreGive( xSemaphore ) != pdTRUE )
{
// We would not expect this call to fail because we must have
// obtained the semaphore to get here.
}
}
}
}
In a synchronous bus, the bus system processes are synchronized by way of a clock signal. The bus system clock is provided from the computer system clock, even though it is usually slower than the master clock. Just as an example, 0.6GHz bus systems are used in computer systems with a processor clock of over 5GHz (Matthew, 2004). Bus systems are usually slower than processors. The reason is because memory access times are generally longer than clock cycles of the processor. A bus transaction sometimes takes many clock
A state variable known as congestion window is implemented by the TCP protocol which stops the clogging of the network by regulating and putting a limit on the data that is sent on the network in turn reducing congestion, timeouts and lost packets.
In 1982 the company Johnson & Johnson, recalled 31 million bottles of Tylenol from store shelves after eight people in the United States died from cyanide-laced capsules. The recall cost Johnson & Johnson $240 million dollars and cut its profit on five billion dollars in revenue in 1982 by almost 50 percent. Although the tampering was no fault towards the company, Johnson & Johnson decided to act before it had complete information on the entirety of the unfortunate situation. As a result, the Tylenol product containers were redesigned and new tamperproof packaging was introduced. The company’s immediate response to the problem saved the Tylenol brand and won the company admiring reviews for their immediate action and their ethical and moral prowess. The move turned out to be a huge marketing coup for the company of which resulted in significant goodwill from customers (Seglin, 2000). Johnson & Johnson’s ethical practice proved to be a great guide, displaying the imperative of being both socially and ethically accountable for the lives of others.
This critical review will look at the skill of administering antipsychotic depot intramuscular injections. This skill was practised while I was on my psychiatric placement in a community setting. The setting will not be named for confidentiality reasons as set out by An Bord Altranais. According to An Bord Altranais (2008), under no circumstances may a student nurse disclose a health care facility’s identity in an assignment. Clinics were run twice a week in this particular community setting for patients with mental health problems such as schizophrenia and bipolar affective disorder to receive their depot intramuscular injections. This skill was chosen as the author was practising administering intramuscular injections almost on a daily basis but there is confusion around what is the best practice for administering depot intramuscular injections in the mental health setting.
The ten videos I watched were: Coronoa “Shoes”, Coors Light with Ice Cube, Captain Morgan, Bud Light “Swear Jar”, Bud Light “Clothing Drive”, Budweiser “Puppy Love”, Budweiser “Clydesdale Donkey”, Smirnoff with Pharrell Williams, Jose Cuervo Silver, and Patron Silver. Most of the focuses on minors were pretty obvious, but a few were hard to recognize. Ten out of the ten ads could target those under 21.
One of the main reasons this research was conducted was to understand how multitasking on your computer during class affects the student and his/her peers around them. This research is very topical, considering that technology is becoming extremely prevalent in our everyday tasks. The results of this study provided that multitasking does have consequences on the student and their peers (Sana. F., Weston, T., & Cepeda, N. J., 2013). To begin with, the study proved that learning and understanding declined when multitasking was introduced (Sana, et. al., 2013). Another thing Sana, Weston, and Cepeda (2013) found was that comprehending the material presented during lecture was also disrupted when students were sitting near another student who was multitasking.
America has evolved over the centuries, from a British colony to an international powerhouse. At one point, the U.S was considered the greatest country in the world. America always found solutions to problems, and tried to help make peace throughout the world, but now that is up to debate. Why? The answer is simple, the government. The dishonesty and bad decisions have resulted in America’s title as a superpower to waver. The government is a growing problem that may lead to the demise of America by negatively affecting political, social, and economic issues in the country.
Do you believe that because Canada is a multicultural society that there is no racism? While the idea of inclusion and buried racism is what one might hope for, the realities of Canada’s national policy when experienced is quiet opposite than the messages expressed though text and other media outlets. Canada is suppose to be a multicultural society which includes all races and cultural backgrounds, everyone is suppose to be included and accepted in our group instead there are instances of discrimination and marginalization to certain racialized groups that have entered Canada the land that is promised to be of freedom and inclusion for all. Multiculturalism is a fundamental characteristic of the Canadian heritage and identity it is what fills our national center. (Harmony 2014). Multiculturalism has been a good policy designed to give people a great impression of our country yet: The Novels Indian Horse (2012) by Richard Wagamese and Obasan (1981) by Joy Kogawa portrays acts of violence, terror, exclusion and hardship. It is observed through reading and analysis that Racism is a never-ending struggle that people of minority backgrounds who immigrate to the land of the free have to endure. Finally, Racism stifles and affects everyone negatively who is an immigrant in the Canadian society; multiculturalism is only a façade which serves to cover up the root of the problem.
Here we can say that the link between signified and signifier is essential. Signifier, is the particular term to describe the physical part that is analysed and is characterizable as an observer.... ... middle of paper ... ...
As per my own experience with an informative speech; a several years back, while taking an IT course at the Kingsborough Community College in Brooklyn, it was a part of my assignment to write and deliver an informative speech on the topic of “The Evolution of CPU”, which covered the development and history of Central Processing Unit, organized in chronological order, from the early models to the latest and most advanced products.
1. Leadership is influence, how would you influence others as a leader? I would influence others firstly, by setting an example myself. Being an example of hard work and confidence will influence others in their work. I’m also willing to help anyone with their work which will be buying first within our chapter.
Cell phones have immensely changed the way people communicate today. A cell phone can be all a person need for interaction. From a cell phone, a person can make calls, send text messages, emails, and send and also receive directions, buy things online, do online banking, listen to music and much more. Since someone can do everything with one device, there is no longer a need to go around with multiple devices about. Greek hydraulic semaphore systems were used as early as the 4th century. The hydraulic semaphores, which functioned with water filled containers and visual signals, functioned as optical telegraphs. However, they could only apply a very limited range of pre-determined messages, and as with all such visual telegraphs could only be deployed during good visibility conditions. Experiments on communication using electricity was carried out in 1729 but was not successful. The experiment was proposed by William Fothergill Cooke. In 1837, William invented a practical electric telegraph which entered commercial use in 1838 (J. B. Calvert, May 2004). The first telephone was invented in 1878 by Alexander Graham Bell. He experimented with a ‘phonautograph’, it is a machine shaped like a pen that can draw shapes of sound waves on smoked glass by tracing vibrations.
Communication is an interdependent process of sending, receiving, and understanding messages. The definition implies that the components of the communication process cannot be examined separately. Rather, the relationship exists between the sender and the receiver, as well as the environment of the communication event, must be viewed as a whole. According to this perspective, if any of the components and circumstances change (that is, the number of individuals involved in the interaction, seating arrangements, or the time of the day) the communication event is altered. Communication is an ongoing process; we never stop sending and receiving messages. As we will discover, communication is a dynamic process, a process that changes from one communication setting to the next. Although it is difficult to predict, the ways of interpreting communication, certain components are always present in the communication process.
This report will describe the two forms of data communications in terms of the physical interfaces and modes of operation. It will describe the features of data communications equipment in relation to synchronous and asynchronous communication including modems, network terminating units and sending and receiving equipment.
Computers are very complex and have many different uses. This makes for a very complex system of parts that work together to do what the user wants from the computer. The purpose of this paper is to explain a few main components of the computer. The components covered are going to be system units, Motherboards, Central Processing Units, and Memory. Many people are not familiar with these terms and their meaning. These components are commonly mistaken for one and other.