EDF uses priorities to the jobs for scheduling. It assigns priorities to the task according to the absolute deadline. The task whose deadline is closest gets the highest priority. The priorities are assigned and changed in a dynamic fashion. EDF is very efficient as compared to other scheduling algorithms in real-time systems. It can make the CPU utilization to about 100% while still guaranteeing the deadlines of all the tasks.
EDF includes the kernel overload. In EDF, if the CPU usage is less than 100%, then it means that all the tasks have met the deadline. EDF finds an optimal feasible schedule. The feasible schedule is one in which all the tasks in the system are executed within the deadline. If EDF is not able to find a feasible schedule for all the tasks in the real-time system, then it means that no other task scheduling algorithms in real-time systems can give a feasible schedule. All the tasks which are ready for execution should announce their deadline to EDF when the task becomes runnable.
embedded real time operating systems by rajkamal pdf free 11
1. Which memory storage is widely used in PCs and Embedded Systems?a) EEPROMb) Flash memoryc) SRAMd) DRAMView AnswerAnswer: dExplanation: DRAM is used in PCs and Embedded systems because of its low cost. SRAM, flash memory and EEPROM are more costly than DRAM. var adpushup = window.adpushup = window.adpushup ; adpushup.que = adpushup.que []; adpushup.que.push(function() adpushup.triggerAd("9f8aa9b5-2c42-4296-896e-70772ed1db59"); ); 2. How is the protection and security for an embedded system made?a) Security chipsb) Memory disk securityc) IPRd) OTPView AnswerAnswer: cExplanation: Intellectual property right provides security and protection to embedded systems.3. Which of the following task swapping method is a better choice in the embedded systems design?a) time sliceb) RMSc) cooperative multitaskingd) pre-emptiveView AnswerAnswer: dExplanation: The pre-emptive method of task swapping is the first choice for embedded system design because of its better system response.4. Which type of memory is suitable for low volume production of embedded systems?a) Non-volatileb) RAMc) Volatiled) ROMView AnswerAnswer: aExplanation: The devices which use non-volatile memory allow the software to be download and returned in the device. UV erasable EPROM is favorable but EEPROM is also gaining favor. Therefore, this type of memory is used in low volume production.5. Which activity is concerned with identifying the task at the final embedded systems?a) schedulingb) task-level concurrency managementc) high-level transformationd) compilationView AnswerAnswer: bExplanation: There are many design activities associated with the platforms in the embedded system and one such is the task-level concurrency management which helps in identifying the task that needed to be present in the final embedded systems.advertisement var adpushup = window.adpushup ; adpushup.que = adpushup.que []; adpushup.que.push(function () { if (adpushup.config.platform === "MOBILE") adpushup.triggerAd("e5da93a0-b61a-4789-96be-a57ebec165b0"); else if ((window.outerWidth
12. Which of the following is a traditional method for emulating the processor?a) CPU simulatorb) SDSc) ICEd) Low-level language simulatorView AnswerAnswer: cExplanation: The SDS is one of the simulation tool used in the embedded systems. CPU simulator and the low-level simulator are the other kinds of the simulator used in the embedded system design.13. Which of the following unit protects the memory?a) memory management unitb) peripheral unitc) execution unitd) bus interface unitView AnswerAnswer: aExplanation: The resources have to be protected in an embedded system and the most important resource to be protected is the memory which is protected by the memory management unit through different programming.14. Identify the standard software components that can be reused in an embedded system design?a) memoryb) application softwarec) application managerd) operating systemView AnswerAnswer: dExplanation: There are certain software components that can be reused in an embedded system design. These are the operating systems, real-time databases and some other forms of middleware.advertisement var adpushup = window.adpushup ; adpushup.que = adpushup.que []; adpushup.que.push(function () { if (adpushup.config.platform === "MOBILE") adpushup.triggerAd("21eae76a-c83f-42b0-aec5-01d590a53f37"); else if ((window.outerWidth 2ff7e9595c
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