Embedded C,RTOS interview questions with answers

1) What is RTOS and why do we go for it?
     RTOS sheludes execution in a timely manner,manages system resources and provides a consistent          foundation for developing application code.
     Application code designed for RTOS could be ranging from simple digital stopwatch to complex            aircraft navigation systems.

RTOS differs from the GPOS by
  Task scheduling : RTOS like vxWorks,neclueos, uC/OSII uses a strict scheduling algorithms (like pre-     emptive scheduling) that makes the tasks meet their deadline to get the job done.
  
The sheduler decides which task run when by knowing its priorities.Whereas In a GPOS, the scheduler typically uses a "fairness" policy that offers no assurances that high-priority, time-critical tasks will execute in preference to lower-priority tasks.This policy is maintained to obtain the overall output by the desktop pc or server pc.

2) What are the different types of semaphores in vxworks RTOS? Which is the fastest?
     VxWorks supports three types of semaphores.
     1) Binary 2) mutual exclusion, and 3)counting semaphores.
     Fastest : Binary semaphore.

 3. What is priority inversion ? why priority inversion occurs?
     Tasks in RTOS's communucates between them via IPC source semphores for synchornization.
     The situation priority inversion occurs when a higher priority taks is ready to run but it is waiting for       a shared resource that is to be released by a lower priority task currently running .Now higher-                 priority task is pending on the resource and it has to wait until the lower priority task to finish.

4. What are the solutions for priority inversion ?
    1) Priority inheritance
    2) Priority ceiling

Technical Interview Questions @cdac Placements

1. Design and Gate using Mux?
2. Explain about Linking (Dynamic & Static)?
3. Write a function to insert a node in the linked list for the given position ?
4. What are the methods to find out the stability of a system?
5. How to find the stability of the system using Poles?
6. Where should we use processes & where to use thread?
7. What are the disadvantages of using array?
8. Explain the advantages of threads over processes?

HoneyWell_interview questions

1. There is a thermometer which can measure -100⁰C to 100⁰C. Test that thermometer for some values. What are those values, were would it fall?

2. What is a device driver?

3. What is ROTS, name some Rtos and difference b/w Hard Real Time OS & Soft Real Time OS?

4. What is clipper?

5. Draw the symbol of Zener diode?

6. What is flip-flop? Draw S-R flip flop?

7. What are Multivibrators, How can we make them?

8. What is Major Id – Minor Id Device Drivers?

9. What type of scheduling is done in windows?

10. What is Preemptive Scheduling?

11. Write a C-program for stack?

12. What is namespace?

13. What is function overloading?

14. What is Inline function?

15. What is header file?

16. How would static and local variables behave when Main is called recursively?

17. How Kernel works, take an example and explain?

18. Why do want to join honey well?

19. If I give you .Net & DBMS would you join ?

20. GD-Topic-Are Engineers wasting time in Management studies?

............ Submitted by Ashwin_HoneyWell_DESD_AUG_10

HoneyWell_interview questions

1. introduction your self
2. what is your rate in C,C++
3. Explain about storage classes
4. difference between break and continue
5. A=5,B=3,        C=a&bè

                  C=A||bè

                                    C=A^bè

6. He given one simple prgm tell me output

            Int i=6

If (i=5)

{ printf(“hi”)

}         

Else

{

Printf(“bye”)

}

7. Functon pointers Array of pointers
8. Difference between microprocessor and microcontroller or not how to interface ADC to microcontroller
9. what is generator, principal of generator
10. what is op-amp, Advantage of op-amp
11. design 555 timer using op-amp
12. polymophsim in C++

Mind tree interview Questions

   

1. Tell me about your self
2. Explain about 
1. Function pointers
2. call backs
3. compilation process
3. how malloc works

char *ptr  (char*)(malloc(100))

free(ptr);

                  how free knows that it has to deallocate 100Bytes

6. how sizeof(x) id implemented
7. programs related to strings

1. string reverse with out temp array
2. string copy
3. concatenate string *int & return string

         eg: “hellop”10;

                return hello10 as sting

CDAC_Patni _ Interview Questions _

1.       Difference b/w ARM & thumb mode?

2.       PC microcontroller architecture & advantages?

3.       Timing diagram for SPI protocol & Explain with EEPROM interface?

4.        Tcp/ip ,UDP Protocols ?

5.       IR, RFID, Bluetooth, Zigbee, Wi-Fi, Winmax Examples & ranges?

6.       Bus protocols: I2C, SPI, CAN & its difference?

7.       ARM series difference & applications?

8.       What is code density?

9.       What are the bits in Thumb Mode?

10.   What is a device driver?

11.   Difference b/w Linux & windows? And its advantages and disadvantages?

12.    Zigbee inbuilt Protocols? What are the companies manufacturing the zigbee with stack protocols?

13.   Explain about the Bluetooth briefly?

14.   Zigbee wireless network details & explain with home made applications?

15.   What are the difference fields in Embedded Domain?

·        Consumer electronics

·        Medical electronics

·        Automation control

·        Wireless & mobile

16.   Circular Linked List program for creating & counting the number of nodes& print?

17.   Logic of double linked list?

18.   Diff b/w OS & RTOS?

19.   What is Pre-emptive & Scheduling & IPC?

20.   What about Semaphores, Spinlocks & Mutex?