US Drug Policy essays

US Drug Policy articles Q. Would the Amsterdam model be a valuable government reaction to psychedelic drug and maryjane use in this nation? Why or why not? Amsterdams coffeehouses and bistros are infamous for the endured trade of hashish and maryjane. This model goes totally against the ethical standards basic the United States sedate approach. The United States sedate arrangement remains by the zero resilience rules. Our medication culture doesn't trust in any such thing as an utilization of an illicit medication, just maltreatment. All in all, why arent the Dutch looking the same number of medication related issues as we seem to be? Is a more free enterprise way to deal with drugs the appropriate response? We arent winning the war on drugs. Obviously the illicit medication use and medication related issues have expanded in the United States. I feel that the Amsterdam model may act a valuable government reaction to drug and cannabis use in the United States. We have had a go at everything from stricter disciplines to spending more dollars on tranquilize avoidance programs. The counter medication law has prompted the criminalization of more medications and the detainment of more medication clients. The expense of preclusion of medications is getting pricier consistently. Lester Grinspoon and James Bakalar expressed, The capture of in excess of 300,000 individuals per year on pot charges contributes the stopping up of courts and the congestion of detainment facilities. Administrative, state, and nearby governments currently spend almost ten billion dollars per year on sedate implementation and several millions more to house and feed street pharmacists and clients in neighborhood, state an d bureaucratic prisons(80). The medication related issues are expanding as opposed to diminishing. Isnt it time that we looked for a superior option in contrast to battling the war on drugs. I am not saying that authorizing all medications is the arrangement. I certainly dont accept that authorizing all medications would work in our general public. I dont feel that our general public is sufficiently adult to deal with the responsib... <!

Role of Global Mncs in Governance

Question: Examine about theRole of Global MNCs in Governance. Answer: Presentation: In the period of globalization, the spread of tasks of worldwide companies has become remarkable which has prompted humongous riches age. Such is the limit of riches age of these organizations that they overshadow the absolute GDP of a large group of countries including some greater countries. It is assessed that the MNCs create a deals in overabundance of USD 28 trillion yearly and give direct work to more than 70 million individuals internationally. Because of this tremendous spread and riches creation, there emerges the requirement for them to ensure their business advantages which requires aberrant impedance in administration through intrigue with lawmakers and other powerful partners (Cutler, 2003). It is basic that the manufacturing of implied associations with MNCs serves the administration well particularly in immature and creating countries. This is on the grounds that the majority of these countries are offered with rich mineral assets and other factor enrichments however come up short on the imperative capital, innovation and the board to abuse these assets. Subsequently, the national governments leave the line to give these MNCs an empowering domain in order to boost them for setting shop. In any case, simultaneously, the administration winds up surrendering its self-sufficiency by giving up to the benefit making goals of these organizations. In the guise of bringing advancement, these MNCs request charge credits and assurances from the administration with respect to security from nationalization (Detomasi, 2015). There are visit intercessions in the strategy circle which are custom fitted according to these requirements particularly with respect to work guideline. Simult aneously, there are unfriendly ramifications for the household businesses, work and furthermore the nearby condition. Consequently, while these nations expect that they are picking up, there are really not increasing much as the drawn out impacts negative impacts are basically covered up (Cutler, 2003). In the created world, the job of government has subsided since the time Thatcherism has picked up predominance and privatization has increased a strong hold. This outcomes in even fundamental administrations being privatized for the sake of productivity. Notwithstanding, in specific cases, an imposing business model is made which in conspiracy with government officials is misused because of which the purchasers need to pay utility charges that are nonsensically high. An a valid example is that of Enron which has built up a virtual restraining infrastructure on vitality exchanging business the US and consequently could control the power costs by utilizing political contacts (Gourevitch Shinn, 2005). From the abovementioned, it might appear that MNC will in general maltreatment their capacity so as to serve their inclinations. Through the guide of CSR (Corporate Social Responsibility) quantifies, these MNC can conceivably go about as change operators particularly for the poor countries (Detomasi, 2015). In any case, there is no precluding that on account from securing their financial force, MNC would keep on going about as noteworthy players in the administration. The essential methodology is to guarantee that responsibility of utilization of this force is improved through worldwide measures by including buyer mindfulness. Likewise, the state guideline component should be reinforced in order to restore sufficient balanced governance to forestall maltreatment of intensity (Abbott Snidal, 2009). References Abbott, KW Snidal, D 2009, Strengthening global guideline through transnational new administration, Vanderbilt Journal of Transnational Law,vol. 42, no.2, pp. 501578 Cutler, C 2003, Private force and worldwide position: Transnational dealer law in the worldwide political economy, fourth ed., Cambridge University Press, Cambridge Detomasi, D 2015, The Multinational Corporation as a Political Actor: Varieties of Capitalism Revisited, Journal of Business Ethics, Vol. 128, No.3, pp.685-700 Gourevitch, PA Shinn, J 2005, Political force corporate control: The new worldwide legislative issues of corporate administration. third ed., Princeton University Press, Princeton

Hancock, John

Hancock, John Hancock, John, 1737â€"93, political leader in the American Revolution, signer of the Declaration of Independence, b. Braintree, Mass. From an uncle he inherited Boston's leading mercantile firm, and naturally he opposed the Stamp Act (1765) and other British trade restrictions. In 1768 his ship Liberty was seized as a smuggler and confiscated by the crown. A riot ensued, and later the ship was burned. Hancock was hailed as a martyr and elected (1766) to the legislature, where he joined Samuel Adams in advocating resistance to England. In 1775, Gen. Thomas Gage issued a warrant for their arrest, but they escaped. Hancock was a member (1775â€"80, 1785â€"86) and president (1775â€"77, 1785â€"86) of the Continental Congress. His name appears first (and largest) on the Declaration of Independence, and the term John Hancock is often used to mean a signature. He was governor of Massachusetts (1780â€"85, 1787â€"93). See biographies by L. Sears (1912, repr. 1972), W. T. Baxter (1945 ), H. S. Allan (1948), and F. Wagner (1964). The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved. See more Encyclopedia articles on: U.S. History: Biographies

My Writing Style And Writing - 890 Words

Writing was never a known weakness of mine. However, I could never confidently call it a strength. Throughout the course of this semester, my writing style has evolved and I have rid my writing of many habitual mistakes. I have learned to appreciate writing much more, and enjoy the moments where my mind meets words on a paper. Creativity has always been one of my strong suits, but through this course I catered my creativity to compose a variety of essays and speeches. Likewise, public speaking is something that I did not struggle with in the past, yet the structure of the class required a video speeches which was fairly new to me. All in all, I have been able to identify and modify gaps in my composition of writing and speech as a result of this course. In high school, I took both AP English Language and AP English Literature. These courses prepared me well for college composition courses, but left me in the dark regarding the personal style development in writing and writing patterns. I was trapped in the high school, five-paragraph essay form that constricted my thoughts for so long. Discourse 300 enabled me to move past the form and explore new ways to compose writing. This in turn has made my thoughts more complex and concise. I have learned to sustain a logical argument in a much more organized manner and justify it as well. My writing was finally rid of all the â€Å"fluff† and â€Å"padding† that was a necessity in high school to reach a word count. Another improvement I madeShow MoreRelatedMy Writing And Writing Style Essay1300 Words   |  6 Pagesbutterfly, my writing style transformed from something mediocre to something quite exceptional. In high school, even when I took advanced placement English and Lit erature courses, I was never good at writing. My writing would lack structure, reasoning, syntax, and a well-defined thesis statement. My inadequate grades on writing assignments lowered my self-esteem, so I assumed I would never enjoy writing papers because I believed I could never improve. However, since attending a university my writing styleRead MoreMy Writing Style Of Writing905 Words   |  4 PagesThroughout this class I have learn many different writing styles. We used APA form of writing to type our paper and essay. I have also learned that it’s good to take your time and spend more time thinking about what to write, other than just righting a paper right off back. I have learned that it’s not a good idea to write a paper on the day it’s done, that’s more like a ruff daft. My teacher have helped me understand different point of writing. Which all writing deal with an ethos, pathos and logos, eitherRead More My Writing Style1718 Words   |  7 PagesWhenever I get a writing assignment for class, it seems like a chore. 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My writing skills have only gotten betterRead MoreMy Personal Writing Style1549 Words   |  7 Pagespeople speak around 16000 words a day (Huynh). On the other hand, writing is a more formal and concise way of communication than speaking. However, a person need to practice in order to write well. Throughout years, its writing habit developed, writing style progressed, and writing content varied. In this essay, I would reflect on my own writing process now, how my writing progressed throughout three years in PRISMS, and On Writing. Writing starts with thinking about a prompt. I think about what I wantRead More My Writing Style Essay1173 Words   |  5 PagesMy Writing Style We all have a style, and it would seem that I wouldnt know another style, better than I know my own. However, I really wasnt aware that every circumstance causes me to change my style accordingly. It seems that we are all just actors and actresses, playing various social roles, and yet we think we are being our self. There were times when I was really nervous, perhaps before a job interview or meeting new people, and my mom would say , dont be nervous, just go and beRead MoreMy Writing Style And Skills900 Words   |  4 Pagesme about how I formulate ideas and outlines to my papers and visual works. My writing style and skills have gone through many changes throughout English 150 but by far there have been three areas where I have seen the most improvement. How I compose and formulate my works, using certain resources and how I integrated them into my paper, how I edit those works, and how well I use the advice and guidance from my peers to help me revise or complete my works. Composing and formulating to me should beRead MoreMy Personal Writing Style1334 Words   |  6 Pagesown writing styles, and they choose it depends on the situation. I am a college student, so I have opportunities to write academic writings such as essays and e-mails. I am young, so I use informal writing styles such as slang and abbreviation words. I use both Japanese and English. English is not my native language, so I usually use Japanese more often than English. I worked at the restaurant when I was a high school student in Japan, so I have variable acquaintance. I learned that my writing styleRead MoreMy Writing Style And Abilities994 Words   |  4 PagesFinal Essay Within being enrolled for EN11, as well as EN12, I believe that I have made significant improvements in my writing style and abilities. From the first semester, I struggled with choosing one side of the argument or assignment, focusing on such topic and being more specific about it, rather than incorporating a more general idea of both sides that could be taken. By the end of the semester, I believe I had made noteworthy progress of keying into one idea and focusing on the major detailedRead MoreMy Writing Style Of The Professor961 Words   |  4 Pagesmost thing that I like with this class is the teaching style of the professor. The professor made the course very interesting, because when I came to the Tuesday class, I can learn the knowledge from the Asian American history, and when I went to the Thursday class, I can listen to my classmates’ opinion. This is what I like about the teaching style of the professor. I can actually learn things from the class, and I also can discuss with my classmates about the article. In this letter, I will discuss

Psychological Disorders and Treatment - 993 Words

Tatiana Saunders PS124: Psychological Disorders and Treatment Prof: Marjorie Vandemark Kaplan University Everyone has a personality with character traits, but when these traits are rigid and self-defeating, they may interfere with functioning and even lead to psychiatric symptoms. A psychological disorder is describe as any disturbance of emotional equilibrium, as manifested in maladaptive behavior and impaired functioning, caused by genetic, physical, chemical, biological, psychological, or social and cultural factors. Schizophrenia is a disease that strikes people in their prime. It does not matter who you are, you can be diagnosis with schizophrenia. Many people all over the world are affected by bipolar disorders. There are two†¦show more content†¦The majority of patients with bipolar disorder will experience significant symptoms before the age of twenty-five years the disorder is complicated by co-occurring alcohol or substance abuse. While treating my client Bobby Lopez for about three months he has shown little signs of improvement, He started out with another therapist and was reassigned to me for a further study. Bobby stated that he started feeling down and didn’t really want to come out his house at times he would push his wife of three years away just because his mood was unstable, Bobby recently had a child who just turned 3 months he has had no interaction with playing or taking care of his child due to his mood. Before Bobby came to see a therapist he was drinking very heavily and would drink for sunrise to sundown to bypass the time and to make himself feel better. As we have been working on his drinking in order to help him to improve his mood disorder. The main goals of humanistic therapy in Bobby case is to find out how he will perceive himself here and now and how he can recognize growth, self-direction and responsibilities. This method is optimistic and attempts to help individuals recognize their strengths by offering a non-judgmental, understanding experience. Bobby since his treatment has become a better father to his wife and his child, he has also gained a job and his mood is gotten a lot better. I also still her Bobby onceShow MoreRelatedPsychological And Psychological Treatment Of Psychological Disorders1709 Words   |  7 Pagesefficacy of psychological (non-pharmacological) interventions for psychological disorder? Discuss with reference to difficulties in measuring the effects of psychological treatment. The purpose of this essay is to discuss the different theoretical approaches in the treatment of psychological disorder with the help of psychological treatments. Furthermore I will be discussing the difficulties faced in measuring the effects of psychological treatment. Psychotherapy is the term used for psychological treatmentsRead MoreUnderstanding And Treatment Of Psychological Disorders3783 Words   |  16 PagesThe definition, understanding and treatment of psychological disorders have changed over time. In the dark ages or mid-evil times, people who behaved abnormally were quickly labelled as being mad or being possessed by spirits. The individuals were often held in isolation with their treatments being very cruel and harsh. In the eighteenth century, a French physician named Philippe Pinel challenged the cruel treatment methods and promoted a gentler and more humane approach. According to the AmericanRead MoreTreatments For Psychological Disorders And Behavioral Therapy1978 Words   |  8 Pages2015 Treatments for Psychological Disorders One out of three Americans appear to have needed mental-health treatment at some point within the past two years, according to a study done by Napa Chapter. Mental-health treatments, otherwise known as ‘therapies’, have become an increasingly common practice among the American people. The cause being the increase in the diagnosing of mental-health disorders. With the number of new, and the increasingly common disorders, a number of therapy treatments haveRead MorePsychodynamic Therapy948 Words   |  4 PagesAlthough CBT is the most widely practiced psychological therapy for treating anxiety disorders, there are also a number of others, such as psychodynamic therapy (PDT). PDT focuses on helping the patient to become aware of repressed desires and emotions, as well as the hidden meanings in their thoughts and actions, in order to help manage their disorder (Psychotherapy - NHS Choices, 2015). In the treatment of anxiety, research has shown that PDT is significantly more effective than control conditionsRead MorePsy 496 Week 2 Assignment Methodological Issues Article Review1104 Words   |  5 PagesImplications for research and research training. Practice-based evidence: Back to the future. Psychological treatments: Putting evidence into practice and practice into evidence. Write a three- to four-page article review in which you discuss methodological issues unique to psychological research and analyze basic applied psychological research relevant to the treatment of mental disorders. In your paper, you will discuss the topics of evidence-based practice and practice-based evidenceRead MoreAttention Deficit Hyperactivity Disorder ( Adhd )1734 Words   |  7 PagesAustralian figures of a burden of the disease show that mental health problems occur in approximately 14% of young people aged 4–17 years, and 27 % in the 18–24-year-old age range. Most mental disorders, for example, attention deficit hyperactivity disorder(ADHD), anxiety disorder, mood disorder, psychotic disorder, begin during youth 12–24 years of age, although they are often first detected later in life (Lawrence et al. 2015). Poor mental health is related to other health and development concerns inRead MoreOnline Psychological Intervention: A Feasible Measure to Red uce Treatment Barriers1003 Words   |  5 PagesOnline psychological intervention: A feasible measure to reduce barriers to treatment People with mental disorders often find it hard to access psychological treatment. Common barriers to treatment include limited accessibility, unable to afford treatment, fear of what others might think or say, and not knowing where to go for help (Olfson et. al., 2000). Among these barriers, fear of what others might think or say is particularly prominent for people with social anxiety disorder. People withRead MorePsy 496 Week 2 Assignment Methodological Issues Article Review1114 Words   |  5 PagesImplications for research and research training. Practice-based evidence: Back to the future. Psychological treatments: Putting evidence into practice and practice into evidence. Write a three- to four-page article review in which you discuss methodological issues unique to psychological research and analyze basic applied psychological research relevant to the treatment of mental disorders. In your paper, you will discuss the topics of evidence-based practice and practice-based evidenceRead MoreThe Effectiveness of Medicine in Physiological Disorders Essay995 Words   |  4 PagesPhysiological disorders are characterized as mental disorders. Any abnormality bizarre reactions concerning behavioral or mental state that occurs frequently and that is eventually affecting the person’s life, is considered a psychological disorder. People who suffer from mental disorders have difficulties relating, socializing, communicating, and building relationships because of their mental state. There is a huge variety of psychological disorders. Some are more dangerous for the person and canRead MoreEssay Anxiety Disorders1302 Words   |  6 PagesAnxiety Disorders Anxiety is a normal reaction to stressful situations that helps in the coping process for individuals. On some occasions, anxiety may become so severe that it impairs the ability to cope and can create psychosocial impairment. High levels of anxiety that interfere with daily activities and social interaction are considered a psychiatric disorder. Anxiety disorders are treatable and can have profound effects on the psychosocial aspect of the individuals life. This paper will

Prevention Of Pressure Ulcer Health And Social Care Essay Free Essays

Pressure ulcers, or bed sores, or have been impacting worlds for ages, and turn toing the overall bar of force per unit area ulcers is now a outstanding national health care issue. Despite of all the progresss in medical specialty, surgery, nursing attention, force per unit area ulcers still remains a major cause of mortality. Pressure sore is a common job among old people and those who are immobilise or limited activity like post-operative and other bedfast patients. We will write a custom essay sample on Prevention Of Pressure Ulcer Health And Social Care Essay or any similar topic only for you Order Now ( Bergstorm, 2005 ) Many surveies province that aged are prone for force per unit area ulcer throughout the universe and its going a important issue ( Nakagami et al. , 2007 ) . Pressure ulcer can be defined as a type of hurt that affects countries of the tegument or implicit in tissue of the organic structure due to application of excessively much force per unit area on it. ( Grey et al 2006 ) It develops as a consequence of tissue mortification of the tegument over the bony prominence, due to the obstructor of the blood vass flow caused by the application continual force per unit area on it. ( Lyder, 2003 ) The entire outgo for the bar of force per unit area ulcer is well less when compared to its intervention ( Lapsley H M and Vogels R, 1996 ) . It can do terrible frailty and high health-care outgo. The estimated one-year disbursal for the bar and intervention of force per unit area ulcers has been expected about ?1.4 to ?2.1 billion in the United Kingdom and is measured as a monolithic economic job ( Bennet et al. , 2004 ) . After malignant neoplastic disease and cardio vascular disease, force per unit area ulcers are the 3rd most money devouring disease ( Schoonhoven et al. , 2002 ) Harmonizing to European Pressure Ulcer Advisory Panel ( EPUAP ) the happening rates of force per unit area ulcers are runing from 8-23 % . In acute attention infirmaries in the western states the reported prevalence has wide-ranging between 9-22 % . Bettering the criterion of force per unit area ulcer attention could ini ¬Ã¢â‚¬Å¡uence the estimated one-year outgo and quality of life ( Tannen A et al. , 2004 ) . Harmonizing to Whittington et Al ( 2000 ) the prevalence of 15 % of force per unit area ulcers are recorded on admittance, whereas for the 60 % of the persons there was no specific information about the presence or absence of the force per unit area ulcers. In another survey, it is clear that 12.8 % have already had the frailty on their admittance. Harmonizing to Rycroft-Malone, ( 2000 ) A force per unit area ulcers can develop at any country of the organic structure, but normally occurs over cadaverous prominences. ( Murdoch, 2002 ; Jones, 2001 ) The countries can supposed to develop force per unit area sores are sacrum, heels, cubituss and dorsum of the caput. The visual aspect of force per unit area sore is really fast and therefore the early appraisal and stairss to forestall is really necessary ( George and Malkenson, 2008 ) . Pressure strength and continuance are the two chief factors for the force per unit area ulcer formation because of force per unit area. Pressure strength is the volume of external force per unit area applied on internal tissues whereas continuance is the sum of external force is sustained by internal tissues ( Cullum et al. , 2000 ) Harmonizing to NICE guidelines ( 2003 ) the hazard factors act uponing to develop force per unit area ulcer in an single includes intrinsic hazard factors and extrinsic hazard factors. The intrinsic hazard factors such as decreased mobility or stationariness, centripetal damage, acute unwellness, degree of consciousness, extremes of age, vascular disease, terrible chronic or terminal unwellness, old history of force per unit area harm, malnutrition and desiccation. And extrinsic hazard factors are force per unit area, shear, and clash. Shear is defined as the applied force that can do an opposite, parallel skiding gesture in the planes of an object. The sum of force per unit area exerted has got a direct affect on Shear. ( Pieper B, 2007, Nix DP, 2007 ) . Clash is defined as a superficial, mechanical force directed against the cuticle, ensuing in increased susceptibleness to ulceration ( Pieper B. , 2007 ) . Pressure ulcers are classified harmonizing to different phases as defined by the National Pressure Ulcer Advisory Panel ( NPUAP ) . Originally there were merely four phases, but in February 2007 these phases were revised and two more classs such as deep tissue hurt and unstageable were added to it. Phase IA -Redness of a localised country, normally over a cadaverous prominence. Darkly pigmented tegument may non hold seeable blanching ; as its coloring material may differ from the environing country. Phase IIA – loss of partial thickness corium demoing as a shallow unfastened ulcer with a ruddy or tap lesion bed, without any gangrene. It may besides show as or open or ruptured serum filled blisters. Phase IIIA – The bed of hypodermic fatA may be seen but bone, musculus or sinews are non exposed. Slough may be present but does non cover the deepness of tissue loss. Phase IVA – exposure of bone, sinew or musculus. Slough or may be present on some parts of the lesion bed. UnstageableA – Loss of the thickness of the tegument in which in which the base of the ulcer is covered by gangrene ( xanthous, tan, grey, green or brown ) in the lesion bed. Deep tissue InjuryA – Purple or maroon localised country of discolored tegument or blood-filled blister due to damage of implicit in soft tissue due to force per unit area. The country may be preceded by tissue that is house, painful, and mushy compared to next tissue. ( NPUAP 2007 ) To forestall the formation of force per unit area sores nurses are following a assortment of steps such as hazard appraisal and hazard appraisal tools, altering the place of the bedfast patients on a regular basis, inspecting the force per unit area country on a regular basis and while making personal attention, using unctions or picks over the force per unit area countries, supplying comfy mattresses such as air bed, H2O mattress for the bedridden and immobilise patients, puting pillows under the topographic points prone to organize force per unit area ulcer for the vulnerable peoples, maximise nutritionary position, etc. However the efficiency of all these methods is in treatment and statement. This essay study will collate all the assorted available literatures sing the bar of force per unit area ulcer and suggest the better and good pattern to forestall the formation of force per unit area sore among the high hazard people. The criterion of nursing attention is really of import for the bar and direction of force per unit area ulcers. The lovingness of patients, who are at hazard with force per unit area ulcer, is the chief challenge for nurses ( Sinclair et al. , 2004 ) . Harmonizing to Lewis M et Al 2003 the first measure nurses should do out is the hazard appraisal of patients and it is better to place the patient at hazard in the early phases, so we can forestall the force per unit area sores. It consists of degree of mobility, nutritionary position, degree of consciousness and neurological position, incontinency, centripetal damage, complete patient history, and physical and psychosocial scrutiny measuring mental position and cognitive ability. To back up health professionals there are assessment graduated tables to place the patients at hazard. Harmonizing to Walker D K et Al 2010 tegument attention and wet are indispensable to forestall force per unit area sore. Keeping skin unity is of import for the patient`s at hazard. Furthermore inordinate of wet and waterlessness can breakdown the skin`s opposition. Wherever wet is present, it is of import to clean the part exhaustively. Patients identified at hazard should be bathed one time a twenty-four hours. PH balanced cleansing agent is used to protect the tegument from wet and waterlessness, it is a natural protection mechanism of a tegument. When cleansing the skin day-to-day or in the presence of wet, it is necessary non to utilize utmost force or clash. Eventhough wet can non be controlled, usage skin barriers to protect tegument from wet. Dry tegument besides needs to be prevented by utilizing a pH-balanced moisturizer. The surveies conducted by saleh et Al, ( 2008 ) and Lindergren et al. , ( 2002 ) evidenced that usage of hazard appraisal graduated table is successful in foretelling the formation of force per unit area sore ( Decubitus Ulcer ) .The surveies substantiated the function of hazard appraisal graduated tables and their utility in the bar and direction of force per unit area sores. Harmonizing to Lindergren et al. , 2002 states the dependability of hazard rating graduated table in the anticipation of force per unit area sore formation. However, the alteration conducted by saleh et Al. ( 2008 ) , argues about the decrease in the happening of clinical acquired force per unit area tonss through the regular application of hazard appraisal graduated tables. Their acquisition besides states that opinion of clinical appraisal is besides same valuable as associate with the sensing of force per unit area sore through hazard appraisal graduated table. In add-on, Defloor and Grypdonck, ( 2004 ) besides stated that appraisal tools have a critical function for the bar of force per unit area sore. There are many restrictions for the hazard appraisal tools which may take to supply incorrect positive consequences. The dependability, specificity and feeling of the graduated table are influenced by the preventative method applications. Nurses are utilizing a assortment of hazard appraisal tools based on practical experience they acquired. The hazard appraisal tools are assessed by agencies of numerical tonss. The variables like degree of continency, medicines and nutritionary position will give an mean mark for the hazard patients ( Whitening, N. L. , 2009 ) . Braden graduated table is the universally used hazard appraisal graduated table which includes the variables like centripetal perceptual experience, activity, mobility, wet and the nutritionary position. The hazard appraisal graduated table works in such a manner that every bit shor tly as the patient admitted in the infirmary two measure rating is carried out within the first six hours. The two stairss include the skin appraisal and the hazard appraisal to place the possibility of formation of force per unit area sore ( O ‘ Neil, 2004 ) . Frequent rating and appraisal should be done in every consequent rating at every 12 hours on patients who are at high hazard.In the same manner patients who are at low hazard besides needs to be evaluate often to detect or to place any new hazard factors and supplying suited preventative steps ( O ‘ Neil, 2004 ) . The most normally used tool measuring the force per unit area sore in U.K is the Waterlow force per unit area ulcer hazard appraisal tool. And it is user friendly and recommended by the nurses in U.K. Pancorbo-hidalgo et Al. ( 2006 ) , suggests that the Waterlow force per unit area ulcer hazard appraisal tool has good force per unit area sore thinking ability and sensitiveness which may ensue to acquire incorrect positive consequences. With the waterlow force per unit area ulcer hazard assessment tool among the seven assessment surveies conducted by pancorbo-hidalgo, P.L. et Al. ( 2006 ) they got merely few findings with corrects values. Bergstorm et Al. ( 2001 ) agrees that hazard appraisal is done by graduated tables like Braden graduated table or the Norton graduated table in the infirmaries which is more dependable. However there is no universally accepted hazard appraisal tool to be adopted to forestall force per unit area sore. Besides this, the use of the hazard appraisal tools has their ain bounds in clinical systems. Alternatively, Saleh et Al. ( 2008 ) argues that medical opinion is successful as hazard appraisal tools to find the suited to be delivered. Nevertheless, Pancorbo-Hidalgo et Al, ( 2006 ) Braden and Norton graduated tables were noticed to be good once more at hazard computation than the scientific opinions. On the other manus, harmonizing to NICE guidelines ( 2003 ) hazard appraisal tools can merely be used as an aide-memoire and should non replace clinical judgement. Normal supply of O and foods are indispensable for the tissues, to keep wellness. ( Gottrup 2004 ) . When patients sitting or lying, the force per unit area signifier peculiar portion of the organic structure consequences in the lessening of O causes force per unit area sore ( Defloor 2005 ) . The survey conducted by Kaitani et al. , 2010, Vanderwee et al. , 2007 and Pearson et al. , 2010 reveals the importance of altering the place for the bed ridden or immobilise patient in forestalling force per unit area sore happening. Their surveies evidenced the effectivity of shifting in regular intervals among the vulnerable patients. Repositioning is considered as an effectual control method against force per unit area sores ( decubitus ulcer ) . Harmonizing to Vanderwee et al. , ( 2007 ) the effectivity of force of force per unit area greater in sideway place. He besides suggested that supine place is the comfy place to cut down the consequence of force per unit area on the bony prominence . The experiment conducted by Vanderwee et Al. ( 2007 reveals that more regular repositioning does non really diminish the happening of force per unit area sore. But he recognizes that turning of patients is an effective preventative method. The incidence of force per unit area ulcer is more in patients who are lying down in side manner place. The hazard has been reduced when the patients are lying down in supine place. On the other manus the survey conducted by Peterson et Al. ( 2010 ) argues that the effectivity of shifting is less or non dependable even though it is done by any experient nurse. And he found that after keeping an appropriate force per unit area below 33 millimeter of Hg cut down the incidence of force per unit area ulcer. He states that by making this there is still opportunity of happening force per unit area sore in the hazard countries. While turning the patient they are non droping the all countries prone to coerce consequence with the tegument. Even though the standard methods for forestalling force per unit area sores are maintained the tegument dislocation go oning as the hazard countries are non relieved from force per unit area. The survey conducted by Kaitani et Al. ( 2010 ) evidenced that patients enduring from force per unit area sore have done merely a fewer alteration of placement and turning. In their surveies they states that they did n’t noticed any patient s with force per unit area sore who has been changed their place often in a regular intervals. From the findings of Hobbs ( 2004 ) besides reveals that there is no diminution of incidence in force per unit area sore in the infirmary due to the everyday repositioning on older people. Similarly Peterson et al 2010 found that still the incidence of force per unit area ulcer are increasing in the clinical scenes where standard turning of patients has already been done. In EPUAP guidelines ( 2009 ) , suggests that shifting is an effectual method which will diminish the extent and happening of force per unit area over susceptible points like sacrum, heels, cubituss and dorsum of the caput bony prominences. However, there was no research survey conducted by any research workers to cipher the clip spread needed to turn the patient that means there is no grounds of turning intervals from any old surveies or researches. It is really of import to inspect the support surface while making shifting. Patient must be repositioned in regularity after inspecting the tissue viability, call uping degree, medical status and rating of skin unity. It is besides subjected by the supportive surface So shifting can cut down the incidence of force per unit area sore to an extent. In infirmaries and wellness attention places it is suggested that shifting to be done in every 4 hours and by the usage of air mattress the incidence of the happening of force per unit area sore can be prevented. Many of the patient ‘s feels really discomfort while turning often, to avoid frequent turning force per unit area cut downing support surfaces can be used to alleviate force per unit area. Importantly force per unit area alleviating support surface devices has critical function in the bar of force per unit area. Harmonizing to Cullum et al. , 2001 it is divided into two, low tech devices and high tech devices. Low tech devices are soothing support surface to distribute the organic structure weight over an country whereas high devices are jumping support surface where inflatable cells consecutively inflate and deflate. Harmonizing to Lewis M, et Al ( 2003 ) if the patients holding a moderate to high possibility of developing force per unit area sore, dynamic support surfaces include a big cell jumping force per unit area mattress, a low air loss or air fluidized bed, or other force per unit area redistributing systems can be recommended. In a survey conducted by Nixon et Al ( 2006 ) found that in operating tabular arraies, specialized froth mattress sheathings are effectual to cut down the incidence of postoperative force per unit area sores while in other scenes, specialized froth and sheathings were the lone surfaces that were invariably better to standard infirmary mattresses in cut downing incidence of force per unit area ulcers. To diminish the contact between bony prominences and support surfaces, pillows and froths are used. In add-on to that for cut downing the clash and shearing harm, raising devices such as slide sheets, slings or arms can be used to travel the patients. On the other manus, it is ill-defined about the grounds for the advantages of higher-specification changeless low-pressure and alternating-pressure support surfaces for forestalling force per unit area sores. However, there is clinical grounds of a difference in hazard of developing force per unit area ulcers when utilizing high-specification froth mattresses, compared to standard infirmary mattresses. ( Nice 2005 ) Decisions for force per unit area alleviating device should find at hazard appraisal. It must include degree of hazard, comfort, patient`s penchants, general wellness and timing of the surgery. . The surveies conducted by Holm et Al. ( 2007 ) and Ferguson et Al. ( 2000 ) evidenced the significance of nutrition in force per unit area ulcer bar. This survey suggests that older people are largely affected due to coerce ulcer. This is because of their less skin unity and low nutritionary position. The nutritionary position of the aged people is normally related with the degree of consumption of nutrient and fluids along with assorted nursing intercession methods ( Holm et al. , 2007 ) . Management of force per unit area sore and its intervention closely related with the clients nutritionary position. The people with less nutritionary position have a high hazard of happening of force per unit area ulcer. The nutritionary position of the patient has to be assessed by the nurse ab initio. Adequate measure of proteins, Calories, minerals, vitamins and fluids are necessary to keep the tegument unity and lesion healing publicity ( Ferguson et al. , 2000 ) . The promotion and direction of force per unit area sore extremely influenced by their nutritionary position. For making an successful preventative steps it is indispensable to carried out with proper nutritionary rating techniques and planning ( Ferguson et al. , 2000 ) .pressure sore and nutritionary position are closely related to each other and are straight relative to each other.patients who are with less nutritionary position or malnourished are likely to be more prone to develop force per unit area sore ( Thomas, 1997 ) .To cut down the incidence both dietitians and nurses should work jointly. To measure the nutritionary position of the patient and the degree of undernourishment and proper planning and intercessions to be done to better the position if unequal ( Ferguson et al. , 2000 ) .According to EPUAP ( 2009 ) recommendation every wellness attention system should make testing and rating trials of the nutritionary degree of the vulnerable people who are at hazard of force per unit area sore. Pressure sore in bulk instances are preventable and governable. A targeted control step is far better than indicating on handling antecedently recognized force per unit area sores. Preventive steps to fraudulences ( force per unit area ) sore saves clip and money. By making an effectual preventative techniques can besides understate the loss of energy and decrease in the work burden over the wellness attention bringing force ‘s and staffs chiefly nurses. Bergstrom N. , Braden B. , Kemp M. , Champagne M. A ; Ruby E. ( 1998 ) Predicting Pressure ulcer hazard. A multisite survey of the prognostic cogency of the Braden graduated table. Nursing Research. 47 ( 5 ) , p.261-26 Bergstrom N, Braden B. A prospective survey of force per unit area sore hazard among institutionalised elderly. J Am Geriatric S Bennett G, Dealey C, Posnett J. The cost of force per unit area ulcers in the UK. Age Ageing 2004 ; 33:230-5 Cullum N, Nelson EA, Nixon J ( 2000 ) Pressure sores. Clinical Evidence: 979-98 Defloor, T. and Grypdonck, M. F. ( 2004 ) Validation of force per unit area ulcer hazard appraisal graduated tables: a review. Journal of Advanced Nursing. 48 ( 6 ) , p. 613-621. Defloor T, De Bacquer D, Grypdonck MH. The consequence of assorted combinations of turning and force per unit area cut downing devices on the incidence of force per unit area ulcers. International Journal of Nursing Studies 2005 ; 42 ( 1 ) :37-46. European Pressure Ulcer Advisory Panel and National Pressure Ulcer Advisory Panel ( 2009 ) force per unit area Ulcer Prevention Quick Reference Guide. NPtJAP, Washington DC. Ferguson, M. , Cook, A. , Rimmasch, H. , Bender, S. and Voss, A. ( 2000 ) Pressure ulcer direction: the importance of nutrition. MEDSURG Nursing, 9 ( 4 ) . Gottrup F. ( 2004 ) Oxygen in lesion healing and infection. World Journal of Surgery ; 28 ( 3 ) :312-5. Gray, J.E.Enoch, S.Harding, K.G. ( 2006 ) ABC of wound healing.Pressure ulcers.British medical journal.332.p.472-476 Holm, B. , Mesh, L. , and Ove, H. ( 2007 ) . Importance of nutrition for aged individuals with force per unit area ulcers or a exposure of force per unit area ulcers: a systematic reappraisal. Australian Journal of Advanced Nursing, 25 ( 1 ) , p. 77-84. Jones I, Tweed C, Marron M ( 2001 ) A Pressure country attention in babies and kids: Nimbus Paediatric System.A Br J NursA 10 ( 12 ) : 789-95. Kaitani, T. , Tokunaga, K. , Matsui, N. and Sanada, H. ( 2010 ) . Hazard factors related to the development of force per unit area ulcers in the critical attention scenes. Journal of Clinical Nursing, 19, 414-421. Lewis, M. , Pearson, A. , Ward, C. ( 2003 ) Pressure ulcer bar and intervention: Transforming research findings into consensus based clinical guidelines. International Journal of Nursing Practice, 9, p.92-102. Lindgren, M. , Unosson, M. and Krantz, A. M. ( 2002 ) A hazard appraisal graduated table for the anticipation of force per unit area sore development: dependability and cogency. Journal of Advanced Nursing. 38, p.190-199. Lyder, C. , Yu C, Stevenson, D. , Mangat, R. , Empleo- Frazier, O. , Emerling, J. and McKay J. Validating the Braden Scale for the anticipation of force per unit area ulcer hazard in inkinesss and Latino/Hispanic seniors: a pilot survey ( 1998 ) . Ostomy Wound Manage. 44 ( 3A ) p.42S-49S. Murdoch V ( 2002 ) A Pressure attention in the pediatric attention unit.A Nursing standardA 17 ( 6 ) : 71-6 National Institute for Clinical Excellence. ( 2003 ) Pressure ulcer bar. Clinical guideline 7. Nix DP. Support surfaces. In: Bryant R, Nix D, eds. Acute A ; Chronic Wounds: Current Management Concepts. 3rd erectile dysfunction. St Louis MO: Mosby ; 2007:235-248. Nixon, J. , Nelson, E.A. , Cranny, G. , Iglesias, C.P. , Hawkins, K. , Cullum, N.A. , Philips, A. , Splisbury, K. , Dorgerson, D.J. , Mason, S.,2006b. Pressure alleviating support surfaces: a randomized rating. Health Technology Assessment 10 ( 22 ) Nakagami G. , Sakai K. , Matsui N. , Sanada H. , Kitagawa A. , Tadaka E. and Sugama J. ( 2008 ) Validation and finding of the feeling country of the KINOTEX detector to develop a new mattress with an interface pressure-sensing system. Life science National Pressure Ulce Advisory Panel ( NPUAP ) ( 2007, February ) .A Pressure ulcer definition and phases. Retrieved 4/13/2007, fromA hypertext transfer protocol: //www.npuap.org Pancorbo-Hidalgo, P. L. , Garcia-Fernandez, F. P. , Lopez-Medina, I. M. and Alvarez- Nieto, C. ( 2006 ) Risk appraisal graduated tables for force per unit area ulcer bar: a systematic reappraisal. Journal of Advanced Nursing. 54, p. 94-110. Peterson, J. M. , Schwab, W. , Oostrom, V. H. J. , Gravenstein, N.and Caruso, J. L. ( 2010 ) . Consequence of turning on skin-bed interface in healthy grownups. Journal of advanced Nursing, 66 ( 7 ) , p. 1556-1564. Pieper B. Mechanical forces: force per unit area, shear, and clash. In: Bryant R, Nix D, eds. Acute A ; Chronic Wounds: Current Management Concepts. 3rd erectile dysfunction. St Louis, MO: Mosby ; 2007:205-234. Rycroft-Malone J and McInnes EA ( 2000 ) Pressure ulcer hazard appraisal and prevention-technical study London, A Royal College of Nursing Saleh, M. , Anthony, D. and Parboteeah, S. ( 2009 ) . The impact of force per unit area ulcer hazard appraisal on patient results among hospitalised patients. Journal of Clinical Nursing. 18, p. 1923-1929 Schoonhoven, L. , Haalboom, J, R, E. , Bousema, M, T. , Algra, A. , Grobbee, D, E. , Grypdonck, M, H. , Buskens, E. ( 2002 ) Prospective cohort survey of everyday usage of hazard appraisal graduated tables for anticipation of force per unit area ulcers. BMJ, 325, p.1-5. Sinclair, L. , Berwiczonek, H. and Thurston, N. ( 2004 ) Evaluation of an grounds based instruction plan for force per unit area ulcer bar. Journal of Wound, Ostomy, and Continence Nursing. 31 ( 1 ) , p. 43-50. Tannen A, Dassen T, Bours G, Halfens RJG. A comparing of force per unit area ulcers prevalence: concerted informations aggregation in the Netherlands and Germany. Int J Nurs Stud 2004 ; 41:607-12 Thomas, D. R. The function of nutrition in bar and healing of force per unit area ulcers. ( 1997 ) . Clinical Geriatric Medicine. 13, p. 497-511. Vanderwee, K. , Grypdonck, M. and Defloor, T. ( 2007 ) Non-blanchable erythema as an index for the demand for force per unit area ulcer bar: a randomized-controlled test Journal of Clinical Nursing.16, p.325-335. Walker D K, Sell S V, Kindred C. ( 2010 ) Pressure Ulcer Prevention Utilizing Unlicensed Assistive Personnel Crit Care Nurs Vol. 33, No. 4, pp. 348-355 Whitening, N.L. ( 2009 ) Skin appraisal of patients at hazard of force per unit area ulcers. Nursing Standard. 24 ( 10 ) , p.40-44. Whittington, K. , Patrick, M. , Roberts, J, L. ( 2000 ) A national survey of force per unit area ulcer prevalence and incidence in ague attention infirmaries. Journal of Wound, Ostomy and Continence, 27, p. 209-215. How to cite Prevention Of Pressure Ulcer Health And Social Care Essay, Essay examples

Memory system free essay sample

Assume that 32 bits of data are transferred in parallel. If a 133-MHz clock is used, how much time does it take to transfer: (a) 32 bytes of data (b) 64 bytes of data What is the latency in each case? 5. 5 Criticize the following statement: â€Å"Using a faster processor chip results in a corresponding increase in performance of a computer even if the main memory speed remains the same. † 5. 6 A program consists of two nested loops — a small inner loop and a much larger outer loop. The general structure of the program is given in Figure P5. 1. The decimal memory addresses shown delineate the location of the two loops and the beginning and end of the total program. All memory locations in the various sections, 17–22, 23–164, 165–239, and so on, contain instructions to be executed in straight-line sequencing. The program is to be run on a computer that has an instruction cache organized in the direct-mapped manner (see Figure 5. We will write a custom essay sample on Memory system or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page 15) and that has the following parameters: Main memory size 64K words Cache size 1K words Block size 128 words START 17 23 165 Inner loop executed 20 times Outer loop executed 10 times 239 1200 END 1500 Figure P5. 1 A program structure for Problem 5. 6. Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl 362 CHAPTER 5 †¢ THE MEMORY SYSTEM The cycle time of the main memory is 10? s, and the cycle time of the cache is 1? s. (a) Specify the number of bits in the TAG, BLOCK, and WORD ? elds in main memory addresses. (b) Compute the total time needed for instruction fetching during execution of the program in Figure P5. 1. 5. 7 A computer uses a small direct-mapped cache between the main memory and the processor. The cache has four 16-bit words, and each word has an associated 13-bit tag, as shown in Figure P5. 2a. When a miss occurs during a read operation, the requested word is read from the main memory and sent to the processor. At the same time, it is copied into the cache, and its block number is stored in the associated tag. Consider the following loop in a program where all instructions and operands are 16 bits long: LOOP 13 bits 0 16 bits Tag Data Add (R1)+,R0 Decrement R2 BNE LOOP 054E A03C 2 05D9 4 10D7 6 (a) Cache (b) Main memory Figure P5. 2 Cache and main memory contents in Problem 5. 7. Assume that, before this loop is entered, registers R0, R1, and R2 contain 0, 054E, and 3, respectively. Also assume that the main memory contains the data shown in Figure P5. 2b, where all entries are given in hexadecimal notation. The loop starts at location LOOP = 02EC. (a) Show the contents of the cache at the end of each pass through the loop. (b) Assume that the access time of the main memory is 10? and that of the cache is 1? . Calculate the execution time for each pass. Ignore the time taken by the processor between memory cycles. 5. 8 Repeat Problem 5. 7, assuming only instructions are stored in the cache. Data operands are fetched directly from the main memory and not copied into the cache. Why does this choice lead to faster execution than when both instructions and data are written into the cache? Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl PROBLEMS 5. 9 363 A block-set-associative cache consists of a total of 64 blocks divided into 4-block sets. The main memory contains 4096 blocks, each consisting of 128 words. (a) How many bits are there in a main memory address? (b) How many bits are there in each of the TAG, SET, and WORD ? elds? 5. 10 A computer system has a main memory consisting of 1M 16-bit words. It also has a 4K-word cache organized in the block-set-associative manner, with 4 blocks per set and 64 words per block. (a) Calculate the number of bits in each of the TAG, SET, and WORD ? elds of the main memory address format. (b) Assume that the cache is initially empty. Suppose that the processor fetches 4352 words from locations 0, 1, 2, . . . , 4351, in that order. It then repeats this fetch sequence nine more times. If the cache is 10 times faster than the main memory, estimate the improvement factor resulting from the use of the cache. Assume that the LRU algorithm is used for block replacement. 5. 11 Repeat Problem 5. 10, assuming that whenever a block is to be brought from the main memory and the corresponding set in the cache is full, the new block replaces the most recently used block of this set. 5. 12 Section 5. 5. 3 illustrates the effect of different cache-mapping techniques, using the program in Figure 5. 19. Suppose that this program is changed so that in the second loop the elements are handled in the same order as in the ? rst loop, that is, the control for the second loop is speci? ed as for i := 0 to 9 do Derive the equivalents of Figures 5. 20 through 5. 22 for this program. What conclusions can be drawn from this exercise? 5. 13 A byte-addressable computer has a small data cache capable of holding eight 32-bit words. Each cache block consists of one 32-bit word. When a given program is executed, the processor reads data from the following sequence of hex addresses: 200, 204, 208, 20C, 2F4, 2F0, 200, 204, 218, 21C, 24C, 2F4 This pattern is repeated four times. (a) Show the contents of the cache at the end of each pass through this loop if a directmapped cache is used. Compute the hit rate for this example. Assume that the cache is initially empty. (b) Repeat part (a) for an associative-mapped cache that uses the LRU replacement algorithm. (c) Repeat part (a) for a four-way set-associative cache. 5. 14 Repeat Problem 5. 13, assuming that each cache block consists of two 32-bit words. For part (c), use a two-way set-associative cache. Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl 364 CHAPTER 5 †¢ THE MEMORY SYSTEM 5. 15 How might the value of k in the interleaved memory system of Figure 5. 25b in? uence block size in the design of a cache memory to be used with the system? 5. 16 In many computers the cache block size is in the range of 32 to 128 bytes. What would be the main advantages and disadvantages of making the size of cache blocks larger or smaller? 5. 17 Consider the effectiveness of interleaving with respect to the size of cache blocks. Using calculations similar to those in Section 5. 6. 2, estimate the performance improvement for block sizes of 16, 8, and 4 words. Assume that all words loaded into the cache are accessed by the processor at least once. 5. 18 Assume a computer has L1 and L2 caches, as discussed in Section 5. 6. 3. The cache blocks consist of 8 words. Assume that the hit rate is the same for both caches and that it is equal to 0. 95 for instructions and 0. 90 for data. Assume also that the times needed to access an 8-word block in these caches are C1 = 1 cycle and C2 = 10 cycles. (a) What is the average access time experienced by the processor if the main memory uses interleaving? Assume that the memory access parameters are as described in Section 5. 6. 1. (b) What is the average access time if the main memory is not interleaved? (c) What is the improvement obtained with interleaving? 5. 19 Repeat Problem 5. 18, assuming that a cache block consists of 4 words. Estimate an appropriate value for C2 , assuming that the L2 cache is implemented with SRAM chips. 5. 20 Consider the following analogy for the concept of caching. A serviceman comes to a house to repair the heating system. He carries a toolbox that contains a number of tools that he has used recently in similar jobs. He uses these tools repeatedly, until he reaches a point where other tools are needed. It is likely that he has the required tools in his truck outside the house. But, if the needed tools are not in the truck, he must go to his shop to get them. Suppose we argue that the toolbox, the truck, and the shop correspond to the L1 cache, the L2 cache, and the main memory of a computer. How good is this analogy? Discuss its correct and incorrect features. 5. 21 A 1024 ? 1024 array of 32-bit numbers is to be â€Å"normalized† as follows. For each column, the largest element is found and all elements of the column are divided by this maximum value. Assume that each page in the virtual memory consists of 4K bytes, and that 1M bytes of the main memory are allocated for storing data during this computation. Suppose that it takes 40 ms to load a page from the disk into the main memory when a page fault occurs. (a) How many page faults would occur if the elements of the array are stored in column order in the virtual memory? (b) How many page faults would occur if the elements are stored in row order? (c) Estimate the total time needed to perform this normalization for both arrangements (a) and (b). Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl PROBLEMS 365 5. 22 Consider a computer system in which the available pages in the physical memory are divided among several application programs. When all the pages allocated to a program are full and a new page is needed, the new page must replace one of the resident pages. The operating system monitors the page transfer activity and dynamically adjusts the page allocation to various programs. Suggest a suitable strategy that the operating system can use to minimize the overall rate of page transfers. 5. 23 In a computer with a virtual-memory system, the execution of an instruction may be interrupted by a page fault. What state information has to be saved so that this instruction can be resumed later? Note that bringing a new page into the main memory involves a DMA transfer, which requires execution of other instructions. Is it simpler to abandon the interrupted instruction and completely reexecute it later? Can this be done? 5. 24 When a program generates a reference to a page that does not reside in the physical main memory, execution of the program is suspended until the requested page is loaded into the main memory. What dif? culties might arise when an instruction in one page has an operand in a different page? What capabilities must the processor have to handle this situation? 5. 25 A disk unit has 24 recording surfaces. It has a total of 14,000 cylinders. There is an average of 400 sectors per track. Each sector contains 512 bytes of data. (a) What is the maximum number of bytes that can be stored in this unit? (b) What is the data transfer rate in bytes per second at a rotational speed of 7200 rpm? (c) Using a 32-bit word, suggest a suitable scheme for specifying the disk address, assuming that there are 512 bytes per sector. 5. 26 The seek time plus rotational delay in accessing a particular data block on a disk is usually much longer than the data ? ow period for most disk transfers. Consider a long sequence of accesses to the 3. 5-inch disk given as an example in Section 5. 9. 1, for either Read or Write operations in which the average block being accessed is 8K bytes long. (a) Assuming that the blocks are randomly located on the disk, estimate the average percentage of the total time occupied by seek operations and rotational delays. (b) Repeat part (a) for the situation in which the disk accesses have been arranged so that in 90 percent of the cases, the next access will be to a data block on the same cylinder. 5. 27 The average seek time and rotational delay in a disk system are 6 ms and 3 ms, respectively. The rate of data transfer to or from the disk is 30 Mbytes/sec and all disk accesses are for 8 Kbytes of data. Disk DMA controllers, the processor, and the main memory are all attached to a single bus. The bus data width is 32 bits, and a bus transfer to or from the main memory takes 10 nanoseconds. (a) What is the maximum number of disk units that can be simultaneously transferring data to or from the main memory? (b) What percentage of main memory cycles are stolen by a disk unit, on average, over a long period of time during which a sequence of independent 8K-byte transfers takes place? Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl 366 CHAPTER 5 †¢ THE MEMORY SYSTEM 5. 28 Given that magnetic disks are used as the secondary storage for program and data ? les in a virtual-memory system, which disk parameter(s) should in? uence the choice of page size? 5. 29 A tape drive has the following parameters: Bit density 2000 bits/cm Tape speed 800 cm/s Time to reverse direction of motion 225 ms Minimum time spent at an interrecord gap 3 ms Average record length 4000 characters Estimate the percentage gain in time resulting from the ability to read records in both the forward and backward directions. Assume that records are accessed at random and that on average, the distance between two records accessed in sequence is four records. Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl Chapter 5 – The Memory System 5. 1. The block diagram is essentially the same as in Figure 5. 10, except that 16 rows (of four 512 ? 8 chips) are needed. Address lines A18? 0 are connected to all chips. Address lines A22? 19 are connected to a 4-bit decoder to select one of the 16 rows. 5. 2. The minimum refresh rate is given by 50 ? 10? 15 ? (4. 5 ? 3) = 8. 33 ? 10? 3 s 9 ? 10? 12 Therefore, each row has to be refreshed every 8 ms. 5. 3. Need control signals Min and Mout to control storing of data into the memory cells and to gate the data read from the memory onto the bus, respectively. A possible circuit is Read/Write circuits and latches Min D Din Q D Mout Clk Q Dout Clk Data 5. 4. (a) It takes 5 + 8 = 13 clock cycles. Total time = Latency = 13 = 0. 098 ? 10? 6 s = 98 ns (133 ? 106 ) 5 = 0. 038 ? 10? 6 s = 38 ns (133 ? 106 ) (b) It takes twice as long to transfer 64 bytes, because two independent 32-byte transfers have to be made. The latency is the same, i. e. 38 ns. 1 Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl 5. 5. A faster processor chip will result in increased performance, but the amount of increase will not be directly proportional to the increase in processor speed, because the cache miss penalty will remain the same if the main memory speed is not improved. 5. 6. (a) Main memory address length is 16 bits. TAG eld is 6 bits. BLOCK eld is 3 bits (8 blocks). WORD eld is 7 bits (128 words per block). (b) The program words are mapped on the cache blocks as follows: Start 0 1024 17 Block 0 127 128 23 1151 1152 165 Block 1 255 239 1279 256 1200 1280 Block 2 383 1407 384 1408 Block 3 511 1500 1535 End 512 Block 4 639 640 Block 5 767 768 Block 6 895 896 Block 7 1023 Hence, the sequence of reads from the main memory blocks into cache blocks is Block : 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 0, 1, 0, 1, 0, 1, . . . , 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 2, 3 Pass 1 Pass 2 Pass 9 Pass 10 2 Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl As this sequence shows, both the beginning and the end of the outer loop use blocks 0 and 1 in the cache. They overwrite each other on each pass through the loop. Blocks 2 to 7 remain resident in the cache until the outer loop is completed. The total time for reading the blocks from the main memory into the cache is therefore (10 + 4 ? 9 + 2) ? 128 ? 10 ? = 61, 440 ? Executing the program out of the cache: Outer loop ? inner loop = [(1200 ? 22) ? (239 ? 164)]10 ? 1? = 11, 030 ? Inner loop = (239 ? 164)200 ? 1 ? = 15, 000 ? End section of program = 1500 ? 1200 = 300 ? 1 ? Total execution time = 87, 770 ? 5. 7. In the rst pass through the loop, the Add instruction is stored at address 4 in the cache, and its operand (A03C) at address 6. Then the operand is overwritten by the Decrement instruction. The BNE instruction is stored at address 0. In the second pass, the value 05D9 overwrites the BNE instruction, then BNE is read from the main memory and again stored in location 0. The contents of the cache, the number of words read from the main memory and from the cache, and the execution time for each pass are as shown below. After pass No. Cache contents 005E 1 Time MM accesses Cache accesses 4 0 40 ? 2 2 22 ? 1 3 13 ? 7 5 75 ? BNE 005D Add 005D Dec 005E 2 BNE 005D Add 005D Dec 005E 3 BNE 00AA 10D7 005D Add 005D Dec Total 3 Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl 5. 8. All three instructions are stored in the cache after the rst pass, and they remain in place during subsequent passes. In this case, there is a total of 6 read operations from the main memory and 6 from the cache. Execution time is 66 ? . Instructions and data are best stored in separate caches to avoid the data overwriting instructions, as in Problem 5. 7. 5. 9. (a) 4096 blocks of 128 words each require 12+7 = 19 bits for the main memory address. (b) TAG eld is 8 bits. SET eld is 4 bits. WORD eld is 7 bits. 5. 10. (a) TAG eld is 10 bits. SET eld is 4 bits. WORD eld is 6 bits. (b) Words 0, 1, 2,  ·  ·  ·, 4351 occupy blocks 0 to 67 in the main memory (MM). After blocks 0, 1, 2,  ·  ·  ·, 63 have been read from MM into the cache on the rst pass, the cache is full. Because of the fact that the replacement algorithm is LRU, MM blocks that occupy the rst four sets of the 16 cache sets are always overwritten before they can be used on a successive pass. In particular, MM blocks 0, 16, 32, 48, and 64 continually displace each other in competing for the 4 block positions in cache set 0. The same thing occurs in cache set 1 (MM blocks, 1, 17, 33, 49, 65), cache set 2 (MM blocks 2, 18, 34, 50, 66) and cache set 3 (MM blocks 3, 19, 35, 51, 67). MM blocks that occupy the last 12 sets (sets 4 through 15) are fetched once on the rst pass and remain in the cache for the next 9 passes. On the rst pass, all 68 blocks of the loop must be fetched from the MM. On each of the 9 successive passes, blocks in the last 12 sets of the cache (4 ? 12 = 48) are found in the cache, and the remaining 20 (68 ? 48) blocks must be fetched from the MM. Time without cache Time with cache 10 ? 68 ? 10? = 1 ? 68 ? 11? + 9(20 ? 11? + 48 ? 1? ) = 2. 15 Improvement factor = 5. 11. This replacement algorithm is actually better on this particular †large† loop example. After the cache has been lled by the main memory blocks 0, 1,  ·  ·  ·, 63 on the rst pass, block 64 replaces block 48 in set 0. On the second pass, block 48 replaces block 32 in set 0. On the third pass, block 32 replaces block 16, and on the fourth pass, block 16 replaces block 0. On the fourth pass, there are two replacements: 0 kicks out 64, and 64 kicks out 48. On the sixth, seventh, and eighth passes, there is only one replacement in set 0. On the ninth pass there are two replacements in set 0, and on the nal pass there is one replacement. The situation is similar in sets 1, 2, and 3. Again, there is no contention in sets 4 through 15. In total, there are 11 replacements in set 0 in passes 2 through 10. The same is true in sets 1, 2, and 3. Therefore, the improvement factor is 10 ? 68 ? 10? = 3. 8 1 ? 68 ? 11? + 4 ? 11 ? 11? + (9 ? 68 ? 44) ? 1? 4 Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl _ _ 5. 12. For the rst loop, the contents of the cache are as indicated in Figures 5. 20 through 5. 22. For the second loop, they are as follows. (a) Direct-mapped cache Contents of data cache after pass: Block position 0 j =9 i =1 i =3 i =5 i =7 i =9 A(0,8) A(0,0) A(0,2) A(0,4) A(0,6) A(0,8) 1 2 3 4 _ A(0,9) A(0,1) A(0,3) A(0,5) A(0,7) A(0,9) 5 _ 6 7 (b) Associative-mapped cache Contents of data cache after pass: Block position 0 A(0,8) A(0,8) A(0,8) A(0,6) 1 A(0,9) A(0,9) A(0,9) A(0,7) 2 A(0,2) A(0,0) A(0,0) A(0,8) 3 A(0,3) A(0,3) A(0,1) A(0,9) 4 A(0,4) A(0,4) A(0,2) A(0,2) 5 A(0,5) A(0,5) A(0,3) A(0,3) 6 A(0,6) A(0,6) A(0,4) A(0,4) 7 A(0,7) A(0,7) A(0,5) A(0,5) j =9 i =0 i =5 i =9 5 Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl _ _ (c) Set-associative-mapped cache Contents of data cache after pass: Block position 0 1 A(0,9) A(0,3) A(0,7) A(0,7) 2 A(0,6) A(0,0) A(0,4) A(0,8) 3 Set 0 A(0,8) A(0,2) A(0,6) A(0,6) A(0,7) A(0,1) A(0,5) A(0,9) j =9 i =3 i =7 i =9 0 Set 1 1 2 3 _ In all 3 cases, all elements are overwritten before they are used in the second loop. This suggests that the LRU algorithm may not lead to good performance if used with arrays that do not t into the cache. The performance can be improved by introducing some randomness in the replacement algorithm. 5. 13. The two least-signi cant bits of an address, A1? 0 , specify a byte within a 32-bit word. For a direct-mapped cache, bits A4? 2 specify the block position. For a set-associative-mapped cache, bit A2 speci es the set. (a) Direct-mapped cache Contents of data cache after: Block position 0 Pass 1 Pass 2 Pass 3 Pass 4 [200] [200] [200] [200] 1 [204] [204] [204] [204] 2 [208] [208] [208] [208] 3 [24C] [24C] [24C] [24C] 4 [2F0] [2F0] [2F0] [2F0] 5 [2F4] [2F4] [2F4] [2F4] 6 [218] [218] [218] [218] 7 [21C] [21C] [21C] [21C] Hit rate = 33/48 = 0. 69 6 Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl _ _ _ (b) Associative-mapped cache Contents of data cache after: Block position 0 Pass 2 Pass 3 Pass 4 [200] [200] [200] [200] 1 [204] [204] [204] [204] 2 [24C] [21C] [218] [2F0] 3 [20C] [24C] [21C] [218] 4 [2F4] [2F4] [2F4] [2F4] 5 [2F0] [20C] [24C] [21C] 6 [218] [2F0] [20C] [24C] 7 _ Pass 1 [21C] [218] [2F0] [20C] Hit rate = 21/48 = 0. 44 (c) Set-associative-mapped cache Contents of data cache after: Block position 0 Pass 3 Pass 4 [200] [200] [200] [200] 1 [208] [208] [208] [208] 2 [2F0] [2F0] [2F0] [2F0] [218] [218] [218] [218] 0 [204] [204] [204] [204] 1 [24C] [21C] [24C] [21C] 2 [2F4] [2F4] [2F4] [2F4] 3 Set 1 Pass 2 3 Set 0 Pass 1 [21C] [24C] [21C] [24C] Hit rate = 30/48 = 0. 63 7 Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl _ _ _ 5. 14. The two least-signi cant bits of an address, A1? 0 , specify a byte within a 32-bit word. For a direct-mapped cache, bits A4? 3 specify the block position. For a set-associative-mapped cache, bit A3 speci es the set. (a) Direct-mapped cache Contents of data cache after: Block position 0 1 2 _ 3 Pass 1 Pass 2 Pass 3 Pass 4 [200] [200] [200] [200] [204] [204] [204] [204] [248] [248] [248] [248] [24C] [24C] [24C] [24C] [2F0] [2F0] [2F0] [2F0] [2F4] [2F4] [2F4] [2F4] [218] [218] [218] [218] [21C] [21C] [21C] [21C] Hit rate = 37/48 = 0. 77 (b) Associative-mapped cache Contents of data cache after: Block position 0 1 2 3 Pass 1 Pass 2 Pass 3 Pass 4 [200] [200] [200] [200] [204] [204] [204] [204] [248] [218] [248] [218] [24C] [21C] [24C] [21C] [2F0] [2F0] [2F0] [2F0] [2F4] [2F4] [2F4] [2F4] [218] [248] [218] [248] [21C] [24C] [21C] [24C] Hit rate = 34/48 = 0. 71 8 Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl _ _ _ (c) Set-associative-mapped cache Contents of data cache after: Block position 0 Set 0 1 0 Set 1 1 Pass 1 Pass 2 Pass 3 Pass 4 [200] [200] [200] [200] [204] [204] [204] [204] [2F0] [2F0] [2F0] [2F0] [2F4] [2F4] [2F4] [2F4] [248] [218] [248] [218] [24C] [21C] [24C] [21C] [218] [248] [218] [248] [21C] [24C] [21C] [24C] Hit rate = 34/48 = 0. 71 5. 15. The block size (number of words in a block) of the cache should be at least as large as 2k , in order to take full advantage of the multiple module memory when transferring a block between the cache and the main memory. Power of 2 multiples of 2k work just as ef ciently , and are natural because block size is 2k for k bits in the †word† eld. 5. 16. Larger size †¢ fewer misses if most of the data in the block are actually used †¢ wasteful if much of the data are not used before the cache block is ejected from the cache Smaller size †¢ more misses 5. 17. For 16-word blocks the value of M is 1 + 8 + 3 ? 4 + 4 = 25 cycles. Then Time without cache = 4. 04 Time with cache In order to compare the 8-word and 16-word blocks, we can assume that two 8-word blocks must be brought into the cache for each 16-word block. Hence, the effective value of M is 2 ? 17 = 34. Then Time without cache = 3. 3 Time with cache 9 Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl Similarly, for 4-word blocks the effective value of M is 4(1+8+4) = 52 cycles. Then Time without cache = 2. 42 Time with cache Clearly, interleaving is more effective if larger cache blocks are used. 5. 18. The hit rates are h1 = h2 = h = 0. 95 for instructions = 0. 90 for data The average access time is computed as 2 tave = hC1 + (1 ? h)hC2 + (1 ? h) M (a) With interleaving M = 17. Then tave = 0. 95 ? 1 + 0. 05 ? 0. 95 ? 10 + 0. 0025 ? 17 + 0. 3(0. 9 ? 1 + 0. 1 ? 0. 9 ? 10 + 0. 01 ? 17) = 2. 0585 cycles (b) Without interleaving M = 38. Then tave = 2. 174 cycles. (c) Without interleaving the average access takes 2. 174/2. 0585 = 1. 056 times longer. 5. 19. Suppose that it takes one clock cycle to send the address to the L2 cache, one cycle to access each word in the block, and one cycle to transfer a word from the L2 cache to the L1 cache. This leads to C2 = 6 cycles. (a) With interleaving M = 1 + 8 + 4 = 13. Then tave = 1. 79 cycles. (b) Without interleaving M = 1 + 8 + 3 ? 4 + 1 = 22. Then tave = 1. 86 cycles. (c) Without interleaving the average access takes 1. 86/1. 79 = 1. 039 times longer. 5. 20. The analogy is good with respect to: †¢ relative sizes of toolbox, truck and shop versus L1 cache, L2 cache and main memory †¢ relative access times †¢ relative frequency of use of tools in the 3 storage places versus the data accesses in caches and the main memory The analogy fails with respect to the facts that: †¢ at the start of a working day the tools placed into the truck and the toolbox are preselected based on the experience gained on previous jobs, while in the case of a new program that is run on a computer there is no relevant data loaded into the caches before execution begins 10 Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl †¢ most of the tools in the toolbox and the truck are useful in successive jobs, while the data left in a cache by one program are not useful for the subsequent programs †¢ tools displaced by the need to use other tools are never thrown away, while data in the cache blocks are simply overwritten if the blocks are not agged as dirty 5. 21. Each 32-bit number comprises 4 bytes. Hence, each page holds 1024 numbers. There is space for 256 pages in the 1M-byte portion of the main memory that is allocated for storing data during the computation. (a) Each column is one page; there will be 1024 page faults. (b) Processing of entire columns, one at a time, would be very inef cient and slow. However, if only one quarter of each column (for all columns) is processed before the next quarter is brought in from the disk, then each element of the array must be loaded into the memory twice. In this case, the number of page faults would be 2048. (c) Assuming that the computation time needed to normalize the numbers is negligible compared to the time needed to bring a page from the disk: Total time for (a) is 1024 ? 40 ms = 41 s Total time for (b) is 2048 ? 40 ms = 82 s 5. 22. The operating system may increase the main memory pages allocated to a program that has a large number of page faults, using space previously allocated to a program with a few page faults. 5. 23. Continuing the execution of an instruction interrupted by a page fault requires saving the entire state of the processor, which includes saving all registers that may have been affected by the instruction as well as the control information that indicates how far the execution has progressed. The alternative of re-executing the instruction from the beginning requires a capability to reverse any changes that may have been caused by the partial execution of the instruction. 5. 24. The problem is that a page fault may occur during intermediate steps in the execution of a single instruction. The page containing the referenced location must be transferred from the disk into the main memory before execution can proceed. Since the time needed for the page transfer (a disk operation) is very long, as compared to instruction execution time, a context-switch will usually be made. (A context-switch consists of preserving the state of the currently executing program, and †switching† the processor to the execution of another program that is resident in the main memory. ) The page transfer, via DMA, takes place while this other program executes. When the page transfer is complete, the original program can be resumed. Therefore, one of two features are needed in a system where the execution of an individual instruction may be suspended by a page fault. The rst possibility 11 Introduzione allarchitettura dei calcolatori 2/ed Carl Hamacher, Zvonko Vranesic, Safwat Zaky Copyright  © 2006 The McGraw-Hill Companies srl is to save the state of instruction execution. This