Biju Patnaik University of Technology 2008 B.Tech Computer Science and Engineering Eighth Semester - EMBEDDED SYSTEMS PECS 3405 - Question Paper

Eighth Semester Examination-2008
EMBEDDED SYSTEMS
B.Tech PECS 3405
Full Marks – 70
Time: three Hours
ans ques. No. one which is compulsory and any 5 from the rest.
The figures in the right-hand margin indicate marks.
1) Answer the subsequent questions: [Marks two x 10]
a) List down different hardware and software resources in an embedded computer system.
b) Why the response time of LINUX is lower than WINDOWS operating system?
c) What are the parameters used to characterize a real time task?
d) The performance of hierarchical memory system is faster. Why?
e) Why embedded systems are realized as real time systems?
f) Distinguish ranging from hard, soft and firm real time systems.
g) Distinguish ranging from periodic, aperiodic and sporadic tasks in a RTOS.
h) List down at lowest 3 tools that support the design and development of embedded system.
i) What do you mean by release time and response time of real time tasks?
j) List down different hardware and software drivers used in an embedded system.
2)
a) Explain the relationship ranging from OS, computer hardware, system software in an embedded system with the help of a schematic diagram. [Marks 4]
b) What is a system call? discuss the uses of system call in embedded system with an example. [Marks 4]
c) The system calls are implemented as interrupt service routines. Justify. [Marks 2]
3)
a) What do you mean by interface synthesis? Illustrate how the communication time requirements are estimated using process-resource mapping and architectural inputs. [Marks 5]
b) Describe a set of native communication application program interfaces in Java for the communication ranging from Java and the system-on-chip. [Marks 6]
4)
a) What are different criteria to be considered for processor scheduling in an embedded system? discuss different kinds of processor scheduling policies with examples. Which of these is followed in LINUX OS? [Marks 5]
b) 5 batch jobs A through E, arrive at a computer center at almost the identical time. They have estimated running time of 10,6,2,4 and eight minutes. Their (externally determined) priorities are 3,5,2,1 and four respectively, with five being the highest priority. For every of the subsequent algorithms determine the mean process turn-around time, Ignore process switching overhead:
i) Round Robin
ii) Priority scheduling
iii) FCFS(run in order 10,6,2,4,8)
iv) SJF
c) For i) presume that the system is multi-programmed and that every job gets its fair share of the CPU, for (ii) through (iii) presume that only one job at a time runs, until it finishes. All jobs are completely CPU bound. [Marks 5]
a) Discuss the role of tools for the development and debugging of embedded systems. What do you mean by run-control debugging and field debugging? [Marks 4]
b) How does the response time is affected by enabling/disabling interrupts in every kernel service call in a RTOS? [Marks 3]
c) Discuss the kinds of interrupts in embedded C? [Marks 3]

6)
a) A virtual memory system has an address space of 8k words, a memory space of 4k words, and page and block sizes of 1k words. The subsequent page reference modifications occur during a provided time interval. (Only page modifications are listed, if the identical page is referenced again, it isn’t listed twice).
4 two 0 one two six one four 0 one 0 two three five 7
Determine the four pages that are resident in main memory after every page reference change if the replacement algorithm used is
i) FIFO
ii) LRU. [Marks 5]

b) Disk requests come into the disk driver for cylinders 10, 22,20,2,40,6 and 38 in that order. A seek takes six msec per cylinder moved. How much seek time is needed for
i) FCFS
ii) Closest cylinder next, and
iii) Elevator algorithm (initially moving upward).
In all cases, the arm is initially at cylinder 20. State advantages and disadvantages for every method. [Marks 5]
7)
a) Explain briefly various RTOS with examples. [Marks 4]
b) What is the primary goal of a RTOS? [Marks 2]
c) Why RR scheduling policy is improper for time sharing OS? discuss with examples.[Marks 4]
8)
a) Explain the interprocess communication mechanisms in LINUX. [Marks 4]
b) Discuss the message-based interprocess communication in embedded real-time systems and its improper OS support. [Marks 3]
c) How an optimized communication mechanism can be found using message-based interprocess communication. [Marks 3]

Earning:   Approval pending.