Embedded Software Engineer

RISC (Reduced Instruction Set Computer) could carry out a few sets of simple instructions simultaneously. Fewer transistors are used to manufacture RISC, which makes RISC cheaper. RISC has uniform instruction set and those instructions are also fewer in number. Due to the less number of instructions as well as instructions being simple, the RISC computers are faster. RISC emphasise on software rather than hardware. RISC can execute instructions in one machine cycle.

CISC (Complex Instruction Set Computer) is capable of executing multiple operations through a single instruction. CISC have rich and complex instruction set and more number of addressing modes. CISC emphasise on hardware rather that software, making it costlier than RISC. It has a small code size, high cycles per second and it is slower compared to RISC.

In an operating system, there is a module called the scheduler, which schedules different tasks and determines when a process will execute on the processor. This way, the multi-tasking is achieved. The scheduler in a Real Time Operating System (RTOS) is designed to provide a predictable execution pattern. In an embedded system, a certain event must be entertained in strictly defined time.

To meet real time requirements, the behaviour of the scheduler must be predictable. This type of OS which have a scheduler with predictable execution pattern is called Real Time OS(RTOS). The features of an RTOS are

☛ Context switching latency should be short.

☛ Interrupt latency should be short.

☛ Interrupt dispatch latency should be short.

☛ Reliable and time bound inter process mechanisms.

☛ Should support kernel preemption.

Multi-threading provide lot of functionality to the system to allow more than one task can be run at a time. It allows a process to execute faster with less difficulty. But, if there any problem comes in any program or the process than the entire system comes to a halt and slows down the whole system. To control the behavior of this the preemptive multi-threading is used. The control in this case is being shifted from one process to another at any time according to the requirement provided. It allows the program to give the control to another program that is having the higher priority. It includes of many problems like giving of a control by a process half way through in execution and the preemption of the process takes place then the data will be entered as corrupted in the memory location, multi-threading keeps the synchronization that is to be performed between different components of the system and the program and try to avoid the problem mentioned above.

☛ What Source Control systems have you worked with?

☛ What is Continuous Integration? Have you used it and why is it important?

☛ Describe a software development life cycle that you've managed.

☛ How do you react to people criticizing your code/documents?

☛ Whose blogs or podcasts do you follow? Do you blog or podcast?

☛ Tell me about some of your hobby projects that you've written in your off time.

☛ What is the last programming book you read?

☛ Describe, in as much detail as you think is relevant, as deeply as you can, what happens when I type "cnn.com" into a browser and press "Go".

☛ Describe the structure and contents of a design document, or a set of design documents, for a multi-tiered web application.

☛ What's so great about <cool web technology of the day>?

☛ How can you stop your DBA from making off with a list of your users’ passwords?

☛ What do you do when you get stuck with a problem you can't solve?

☛ If your database was under a lot of strain, what are the first few things you might consider to speed it up?

☛ What is SQL injection?

☛ What's the difference between unit test and integration test?

☛ Tell me about 3 times you failed.

☛ What is Refactoring ? Have you used it and it is important? Name three common refactorings.

☛ You have two computers, and you want to get data from one to the other. How could you do it?

☛ Left to your own devices, what would you create?

☛ Given Time, Cost, Client satisfaction and Best Practices, how will you prioritize them for a project you are working on? Explain why.

☛ What's the difference between a web server, web farm and web garden? How would your web application need to change for each?

☛ What value do daily builds, automated testing, and peer reviews add to a project? What disadvantages are there?

☛ What elements of OO design are most prone to abuse? How would you mitigate that?

☛ When do you know your code is ready for production?

☛ What's YAGNI? Is this list of questions an example?

☛ Describe to me some bad code you've read or inherited lately.

☛ What's the difference between Locking and Lockless (Optimistic and Pessimistic) concurrency models?

☛ What kinds of problems can you hit with locking model? And a lockless model?

☛ What trade offs do you have for resource contention?

☛ How might a task-based model differ from a threaded model?

☛ What's the difference between asynchrony and concurrency?

☛ Are you still writing code? Do you love it?

☛ You've just been assigned to a project in a new technology how would you get started?

☛ How does the addition of Service Orientation change systems? When is it appropriate to use?

☛ What do you do to stay abreast of the latest technologies and tools?

☛ What is the difference between "set" logic, and "procedural" logic. When would you use each one and why?

The embedded system should have a function that can allow the fixing the system if anything goes wrong with it. Watchdog timer is a tool that is used in embedded system and having a long-fuse that runs several seconds. Watchdog timer includes the automated timing control that count down the number from max to 0 and when the counter reaches the zero, this WDT reset the micro-controller that gets turned off when the timer was in initial phases. Watchdog require the user to put some value before it runs out of time and reset the whole process as this can harm the data and the system. Resetting by WDT can be done when the process is half complete. Watchdog timer have the counter that is used to watch the processes that are running and if there is any issue occurs then WDT itself times out. The resetting of the system will be done to always give it the best possible way to execute the process.