REAL TIME AND EMBEDDED SYSTEMS

UNIT-I

Introduction: Introduction to embedded systems – processor and memory

organization devices and buses for device networks – device drivers and interrupt

servicing mechanism.

UNIT-II

RTOs: RTOs – programming tools – case studies – hardware – software coo

design in an embedded system.

UNIT-III

Real time systems: basic real time concepts – computer hardware – language

issues – software life cycle.

UNIT-IV

Real time specifications: design techniques – real time kernals – intertask

communication and synchronization –real time memory management.

UNIT-V

Multiprocessing system: Multiprocessing system – hardware/software

integration – real time applications.

TEXT BOOKS:

1. Raj kamal, “Embedded system Architecture, programming and

Design”, Tata Mc Grew Hill, 2003.

2. Phillip A.Laplante,”Real time systems design and Analysis, an

engineer’s Handbook”, Prentice hall of India, 2002.

REFERENCES:

1. R.J.A. Buhr, D.L. Banley, “An introduction to Real time systems:

Design to networking with C/C++”, Prentice hall International, 1999.

2. Grehan Moore and cyliax, “Real time programming” A guide to 32 bit

embedded development reading: addition Wesley-Longman, 1998.

3. Haeth stene, “Embedded system design”, Newnes, 1997.

UNIT-I

PART-A

1. What is a System?

A system is a way of working, organizing or doing one or

many tasks according to a fixed plan, program or set of rules.

A system is also an arrangement in which all its units

assemble and work together according to the plan or program

2. What is Embedded Systems?

A sophisticated system that has a computer as one of its

components. An embedded system is a dedicated computer –based

systems for an application or product.

3. Define Processor?

A processor implements a process or processes as per the

command given to it.

A program or task or thread that has a distinct memory

allocation of its own and has one or more functions or procedures

for specific job.

4. What is Interrupt controller?

A unit that controls the processor operations arising out of an

interrupt from a source.

5. What is Multiplexer?

A digital circuit that has digital inputs from multiple

channels. It sends only one channel output at a time. The channel

at the output has the same address as the channel address bits in its

input.

6. What is Demultiplexer?

A digital circuit that has digital outputs at any instance in

multiple channel. The channel that is connected is the one that has

the same address as the channel address bits in its input.

7. What is Pipe?

A data structure which is sent a byte stream from a data

source and which delivers the byte stream to the data sink.

8. Define Memory Address Register?

A register that holds the address for a memory unit for

placing it on the bus using bus interface unit.

9. Define Memory Data Register?

A register that holds the data for or from a memory unit is

called as Data Register.

10. What is Bus Interface Unit?

A unit to interconnect the internal buses with the external

buses for control address and data bits.

11. What is Program counter?

A processor registers to hold the current instructions address

to be executed after a fetch cycle on the buses.

12. Define Hash table?

A table in which keys are stored as a first column in the table

and values are stored as a second column of a table.

13. What is Serial port?

A port for read and write operations on with one bit at an

instances and where each bit of the message is separated by

constant time intervals.

14. What is Parallel port?

A port for read and write operations on multiple bits at an

instance.

15. What is Control register?

A register for bits, which controls the actions of a device. It is

for a write operation only.

16. What is a Status register?

A register for bits, which reflects the current status at the port

buffer. It is for a read operation only. The bit may not auto-reset on

device servicing.

17. Define I2c Bus?

A standard bus that follows a communication protocol and is

used between multiple ICs.It permits a system to get data and send

data to multiple compatible ICs connected on this bus.

18. Expand PCI Bus.

A standard bus used as “peripheral component Interconnect”

bus.

19. Expand CAN Bus?

A standard bus used at the control area network in

automotive electronics.

20. What is pooling?

A method by which at the end of an instruction or at the end

of an ISR, The pending in interrupts is searched by the processor to

service the one with the highest priority.

PART-B

1. What are the classifications of embedded systems?

2. How about the processor in the systems ?Explain

3. Describe the architecture of a typical micro controller with a neat

diagram?

4. Explain about the interrupts handler in an embedded system?

5. Describe about the embedded systems on chip and in VLSI circuit?

6. Explain the structural units in a processor with a neat diagram?

7. Explain about the memory devices?

8. Explain about the memory maps?

9. Describe about the device drivers?

10. Explain about the virtual devices?

11. Explain about the parallel port drivers in a system?

12. Explain about the serial port drivers in a system?

PART-C

1. Explain about the allocation of memory to program segments and

blocks and memory map of a system.

2. Explain the synchronous and asynchronous communication from

serial devices.

3. Explain the serial communication using the I2c, CAN and

advanced I/O buses between the networked multiple devices.

UNIT-II

PART A

1. What are the two modes in which processor in the system

runs?

User mode: The user process is permitted to run and use

only a subset of functions and instructions in the OS.

Supervisory mode: The OS runs privileged functions in a

protected mode.

2. What is meant by application software?

It executes as per the application run on the given system

hardware using the interfaces and the system software.

3. What is meant by kernel?

The kernel is the basic structural unit of any OS. It can be

defined as a secured unit of an OS that operates in the supervisory

mode.

4. What is the function of process management?

Process management enables process creation, activation,

running, blocking, resumption, deactivation and deletion and

maintains process structure at process control block.

5. What are the components of device manager?

Device drivers and device ISRs(device interrupt

handlers)

Resource manager for the devices

6. What is the function of device drivers?

It facilitates the use of a number of physical devices like

keyboard, display systems, disk, parallel port, network inter face

cards, network devices and virtual devices.

7. What is process manager?

A process manager creates the processer, allocates to each a

process control block manages access to resources and facilitates

switching from one process state to another. The process control

block defines the process structure for a process in a state.

8. What are the two types of file systems?

Block file system

Byte stream file system

9. What is the role of file manager?

The file manager creates, opens, reads, seeks a record writes

and closes a file. A file has a file descriptor.

10. What is Network operating system?

Network operating system is an operating system that

includes special functions for connecting computers and devices

into a local area network.

11. What is RTOS?

An RTOS is an OS for response time controlled and event

controlled processes. An RTOS is an OS for embedded systems,

as these have real time programming issues to solve.

12. What area the three alternative systems in RTOS for

responding to hardware source call?

Direct call to ISR by an interrupting source

Direct call to RTOS by an interrupting source and

temporary suspension of a scheduled task

Direct call to RTOS by an interrupting source and

scheduling of tasks as well as ISR by RTOS.

13. What are the strategies that s scheduler may adopt?

Control flow strategy

Data flow strategy

14. What are the methods by which fixed schedules may be

defined?

Simulated annealing method

Heuristic method

Dynamic programming model

15. What are the three performance metrics?

Ratio of sum of interrupt latencies

CPU load

Worst-case execution time respect to mean execution

time

16. What is meant by protection mechanism?

Protection mechanism is a mechanism at an OS to protect

against unauthorized accesses to the resources

17. What is mobile OS?

Mobile OS is an OS for mobile handheld devices, wireless

devices, palm PCs, and pocket PCs, PDAs and phones.

18. What are the two types of source files?

Processor dependent source files

Processor independent source files.

19. What is meant by service functions?

Service functions mean the functions to task, create, suspend

and resume and time setting and time retrieving functions.

20. What are the tasks of MUCOS memory functions?

Creating memory blocks at a memory address

Getting a memory block at a memory address

Querying a memory block

Putting a memory block into a partition

21. What is meant by counting semaphore?

It is a semaphore that increments when a IPC is given by a

task or a section of the task. It decrements when a waiting task

unblocks and starts running.

22. What is event flag?

It is a flag, which set on occurrence of an event and resets on

response to the event.

23. What is resource key?

A semaphore that resets on the start of execution of a critical

region code and sets on finishing.

24. What is meant by exception handling?

Executing a function on receiving a signal. Error is also

handled by using a exception handling function.

25. What is task delay?

A task wait for a minimum time defined by number of system

ticks passed as an argument to the delay functions.

26. What is adaptive control?

A control system that uses an adaptive algorithm to generate

output control signals.

27. What is protection bit?

A bit at the ROM, which the processor uses for not letting the

instructions and data in the protected part on the system bases.

28. What is Invalidation lock?

A lock, if placed in the application data files in the card, the

card becomes invalid for further use.

29. What is data acquisition system?

A system to acquire data from multiple ports and channels is

termed as data acquisition system.

30. What is meant by adaptive algorithm?

An algorithm that adjust and adapts to the parameters and

limits the changing perturbations in a control system.

31. What is meant by debugging tools?

Debugging tools are tools for debugging embedded system

hardware and software functioning.

32. What are delay zitters?

The delay Zitters mean the random variations in the delays in

retrieving or arrival of successive data sets.

33. What is edit-Test-Debug cycle?

A cycle in implementation phase in which codes are edited

tested and debugged for reported error on test.

34. What is meant by Latency?

Time taken to activate after an event or time taken in

finishing certain codes before next one starts.

35. What is performance index?

Performance index is an index to measure the desired

performance with respect to required specifications.

PART-B

1. What are the goals of OS? Explain briefly.

2. Explain process management.

3. Explain memory management.

4. Explain briefly about network operating system.

5. Explain about interrupt routines in RTOS environment.

6. Explain fixed Real Time scheduling of tasks.

7. Explain about fifteen-point strategy for synchronization between

processes, ISRs.

8. Explain about OS security issues.

9. Explain the need of a well tested and debugged real time operating

system.

10. Explain briefly about semaphore related functions.

11. Explain briefly about mailbox related functions.

12. Explain briefly about Queue Related functions.

13. Explain the use of Vxworks.

14. Explain about case definition, multiple tasks and their functions.

15. Explain about creating a list of tasks, functions and IPCs.

16. Explain about design cycle in the development phase for an

embedded system.

17. Explain briefly about simulator.

18. Explain the use of scopes and logic analyzers for system

hardware tests.

19. Explain about performance modeling.

PART-C

1. Explain in detail about real time and embedded system operating

systems.

2. Explain in detail about RTOS Task scheduling models; interrupt

latency and response time of the tasks.

3. Explain in detail about embedded Linux internals.

4. Explain in detail about use of µc/OS-II.

5. Explain in detail about use of VxWORKS.

6. Explain in detail about case study of coding for sending application

layer byte streams on a TCP/IP network using RTOS VxWORKS.

7. Explain about embedded system for an adaptive cruise control

system in a car in detail.

8. Explain in detail about an embedded system for a smart card.

9. Explain in detail about embedded system design and co-design

issues in system development process.

10. Explain in detail about uses of Target system or its emulator and

ICE.

11. Explain in detail about the use of software tools for development

of an embedded system.

12. Explain in detail about issues in embedded system design

UNIT-III

PART-A

1. What are the basic components of a computer?

Central Processing Unit

Memory

Input/output devices

2. What is Bus?

Bus is connected via a connection of transmission paths

called a bus.

3. Define power bus.

The power bus is the collection of wires used to distribute

power to the various components of the computer system.

4. Define address bus.

The address bus is the collection of wires needed to access

individual memory addresses.

5. Define Data bus.

The data bus is used to carry data between the various

components in the system.

6. What is the discrete signal?

The input / output devices of the computer for example

printer, terminals, plotters and card readers and other devices are

controlled through a signal logic line is called discrete signal .

7. What is interrupt handler return location?

The contents of the program counter are saved to a

designated memory location called the interrupt return location

8. Define failed system.

A failed system is a system that cannot satisfy one or more of

the requirements stimulated in the formal system specification.

9. Write about the types of the memory.

The memory is divided into 2 types.

Main memory which is directly accessible by the CPU.

Secondary memory that characterized by long term

storage devices such as tapes, disks, and cards.

10. Define Application programs.

Application programs are program written to solve specific

problem such as payroll preparation, inventory, and navigation.

Real time design considerations play a role in the design of certain

system program and application software.

11. What are the types of addressing modes?

Implied mode

Immediate mode

Direct mode

Indirect mode

Register direct mode

Register indirect mode

Double indirect mode

12. What is implied mode?

Implied mode instructions involve one or more specific

registers that are implicitly defined in the operation performed by

the instruction.

13. What is immediate mode?

For immediate mode instructions the operand is an integer

that is usually contained in the next address after the instruction.

It requires only two memory fetches and is thus quite fast.

14. What is direct mode?

In direct mode the operand is the data contained at the

address after specified in the address field of the instruction.

This type of instruction requires three bus cycles.

15. What is indirect mode?

Indirect mode instructions requires additional by cycles. It

needs four bus cycles.

One for instruction, another of fetch the operand field

address, a third to fetch the contents of the operand field and to

fetch the data.

16. What is Register Direct mode?

Register Direct mode instructions are similar to direct

instructions except that the operand field is a register and not an

address. This type of instructions requires one bus cycle to fetch

the instruction.

17. Which instructions are allow the memory references?

Memory references are allowed only through LOAD and

STORE instructions. The LOAD instruction moves data from the

specified memory location to the accumulator, while the STORE

instruction moves data from the accumulator to the specified

memory location.

18. What is meant by flip flop and drive line?

The semiconductor material is used to form a bitable logic

device called a flip flop.

Core memory consists of a doughnut shaped magnet through

which a thin wire called drive line passes.

19. Explain about RAM.

RAM memories may be either dynamic or static and are

denoted DRAM and SRAM respectively.

Random Access Memory is both readable and writable

memory.

20. Write about Flash memory.

A new memory technology for programmable ROMs

recently enlarged. The technology called Flash memory uses a

single transistor per bit, where as EEPROM uses two transistor per

bit.

21. Expand EEPROM and UVROM

EEPROM- Electronically Erasable Programmable Read only

Memory.

UVROM- Ultraviolet Read Only Memory.

22. What is actual parameter and formal parameter?

The named variable passed to the procedure which is function

is called actual parameter.

The dummy variable used in the definition of the procedure is

called Formal parameter.

23. What is the difference between call by value and call by

reference?

In call by value passing, the value of the actual parameter is

copied into the called procedure’s formal parameter.

In call by reference or call by address the address of the

parameter is passed by the calling routine to the called procedure

so that it can be altered there.

24. What is Recursion?

Many languages whereby provides a mechanism, called

Recursion where by a procedure can be referential.

That is it can call itself.

Ex:-

Procedure gcd (x, y: integer)

Begin

If(y=0) then

Writeln(x)

Else

Gcd(y, (x mod y))

End;

25. What is Dynamic allocation?

To dynamically allocate memory is important in the

construction and maintenance of stacks.

Dynamic allocation is time consuming it is necessary.

Ex: - The NEW statement in Pascal is used to dynamically

allocate the storage.

26. Write about Exception and Exception handler?

Certain languages provide facilities for dealing with errors

and other anomaly condition that arise during program execution.

Such situations are called Exception.

During runtime, when an exception an exception occurs a

certain code is invoked to handle it. Such code is called an

Exception handler.

27. What is Schedualability analysis?

The compile time prediction of execution time

performance is known as schedualability analysis. In design of

modern real-time languages the emphasis is on elimination those

constructs that render the language no analyzable.

28. What is water fall?

The term waterfall is used to describe the idealized motion

the each stage or phase in the life of a software product occur in time

sequence, with the boundaries between phases clearly defined.

29. What are the phases included in the software life cycle?

Concept phase

Requirements phase

Design phase

Programming phase

Test phase

Maintenance phase

30. What are functional Requirements and Non-functional

requirements?

The requirements document includes specific information

about functional requirements those system features that can be

directly tested by execution the program.

Non-functional requirements are characterized as system

features that cannot easily be tested by program execution.

31. What is detailed design phase?

The design phase is characterized by the conversion of the

requirements document to a detailed design specification is called

a Detailed design phase.

32. What are the steps involved in Maintenance phase?

Product deployment

Customer support

continuing program error correction

PART-B

1. Explain about the basic computer architecture?

2. Write about the software life cycle?

3. Explain the software development standards.

4. Write about the survey of commonly used programming

languages?

5. Briefly explain about Memory?

6. Explain about CPU with diagrams.

7. Explain about input and output devices.

8. What is addressing modes? Explain about their types.

PART-C

1. What are the Basic real time concepts? And explain it briefly.

2. Write about the Language issues briefly.

3. What are the Hardware components? Explain it briefly.

4. Briefly explain about software lifecycle.

UNIT-IV

PART-A

1. List out the difference between specification and design?

Specification: It is performed by the customer tells us what

the software is to do and environment it will function.

Design: It is performed by the system analyst or designer,

tells us how the software will do it.

2. Define CASE?

CASE means Computer-Aided Software Engineering tools, a

graphical specification, for example can immediately be converted

into code.

3. What is structure charts?

Structure charts or callings trees are a widely used

mechanism for

describing the modular decomposition of a system.

In structure charts rectangles are used to represent processes.

4. What is PDL?

PDL means Program Design Languages.

PDL is a type of high-order language that is very abstract; it

is detached from the underlying architecture of the machine.

PDL can be input into a compiler and translated into high-

order languages.

5. List out the methods for representing finite state automata?

Set theoretic method

Diagrammatic method

Matrix representation method

6. What are indexed loop?

The indexed loop construct can be used to specify that a

statement or statements is to be performed n times where n>=0.

Arbitrary label (n) {statements}

7. Define mailboxes?

Mailboxes or messages exchanges are an inter task

communication device available in many commercial full featured

operating system.

A mailbox is a mutually agreed upon memory location that

two or more tasks can use to pass data.

8. Expand SPOOL.

SPOOL is a Simultaneous Peripheral Operation On-Line.

9. What is semaphore?

A methodology for protecting critical regions was suggested

by Dijikstra and involves a special variable called semaphore.

10. What is deadlock?

When tasks are competing for the same set of two or more

serially reusable resources, then a deadlock situation or deafly

embrace may occur.

11. List out the three specific functions of operating system?

Task Scheduling

Task Dispatching

Inter task Communication

12. Define Swapping?

The simple scheme that allows the operating system to

allocate memory or two processes “simultaneously” is swapping.

13. List out the deadlock conditions.

Mutual Exclusion

Circular wait

Hold and wait

No preemption

14. Define Overlays.

A technique that allows a single program to be larger than the

allowable user space is called Overlaying.

15. What is Demand Paging?

In Demand Page systems, program segmented are permitted

to be loaded in non-contiguous memory as they are requested in

fixed size chunks called pages or page frame.

16. What is Counting Semaphore?

A second kind of semaphore called a counting semaphore or

general semaphore can be used to protect pools of resources, or to

keep track of number of free resources.

17. What is context switching?

Context switching is the process of saving and restoring

sufficient information for a real time task, so that it can be resumed

after being interrupted.

18. Define Nano-Kernel.

Simple thread of execution management. It essentially

provides only one of the three services provided by a kernel that is

it provides for task dispatching.

19. Define Leveling.

Once an overall dataflow diagram has been drawn further

detail within the process blocks is provided. The diagram is then

redrawn with the additional detail. This process is called leveling.

20. What are Petri Nets?

Petri Nets are another type of mathematical model used to

specify the operations to be performed in a multiprocessing or

multitasking environment.

PART-B

1. Discuss any four concepts in Real-Time Kernels in detail.

2. Describe the memory management process in Real-Time

Specification.

3. Explain inter process communication and synchronization.

4. Explain any two concepts in Inter task Communication and

synchronization.

5. Discuss in detail about the mailboxes.

6. Describe about the process stack management.

7. List out the Demarks Rules.

8. State about the Kernel hierarchy in detail.

9. Discuss about the Interrupt Driven Systems.

10. State about the full-featured Real-Time operating system.

PART-C

1. Discuss about the Real-Time memory management in detail.

2. Describe the Inter task Communication and synchronization in

detail.

3. Describe briefly about Real-Time Kernel.

4. Discuss about Demand Paging Mechanism.

5. Discuss about the Real-Time specification and design technique.

UNIT-V

PART-A

1. What is multiprocessing systems?

If a real-time systems has more than one processor, that

systems are called multiprocessing systems.

2. What are the types of real-time multiprocessing systems?

There are two types of real-time multiprocessing

systems. They are

Multiprocessing system use several process.

Multiprocessing system use a large number of

interdependent.

3. Define SIMD.

In both systolic and wave front processors, each processing

element is executing the same instruction but on different data.

These architectures are called SIMD.

4. Define MISD.

MISD is a process that processes only one instruction can use

data at any one time.

5. What is MIMD?

In dataflow processors and transporters, each processing

element is capable of executing numerous different instructions

and on different data.

This is called as MIMD.

6. What is Distributed Systems?

Distributed systems are a collection of interconnected self

contained processors.

Distributed systems can perform significant processing

without the co-operation of the other processors.

7. What is Von Neumann-style?

The Von Neumann-style processors provide control and

input/output, whereas the specialized processor is used as an

engine for fast execution of complex and specialized computations.

8. Define Dataflow Architecture.

Dataflow Architecture uses a large number of special

processors in a topology in which each of the processors is

connected to every other.

9. What do you mean by activity packets?

In dataflow architecture, each of the processors has its own

local memory and a counter.

Special tokens are passed between the processors

asynchronously. These special tokens are called activity packets.

10. What is meant by processing elements?

Each processor performs only one specialized operation and

has only enough local memory to perform its designated operation

and to store the inputs and outputs.

The individual processors called processing elements.

11. Define systolic.

Processing at each of the cells occurs simultaneously in

synchronization with a central clock.

The fact that each cell fires on this heart beat lends the name

systolic.

12. Give the purpose of systolic processors.

Systolic processors are fast and can be implemented in

VLSI.

They are somewhat troublesome, however in dealing with

propagation delays in the connection buses and in the availability

of inputs when the clock ticks.

13. What are Systolic processors?

Systolic processors consist of a large number of uniform

processors connected in an array topology.

14. State about the wave front processors.

Wave front processors consist of an array of identical

processors, each with its own local memory and connected in a

nearest neighbor topology.

15. Give the benefits of wave front processors.

Wave front processors are very good for computationally

intensive real time systems and are used widely in modern

real time signal processing.

Wave front architecture can cope with timing uncertainties

such as local blocking, random delay in communications, and

fluctuations in computing times.

16. Define integration.

The process of uniting modules from different sources to

form the overall system is called integration.

17. What is the goal of system integration?

System unification.

System verification.

18. What is system unification?

System unification process consists of linking together the

tested software modules drawn in an orderly fashion from the

source code library.

19. What is load module?

The loadable code is called load module.

This can be downloaded from the development

environment to the target machine.

20. Give the purpose of multimeters.

The multimeters are used to measure of voltage, current or

power and also used to validate the analog input or output into the

system.

21. What is the use of oscilloscope?

It can be used for validating interrupt integrity, discrete signal

issuance, and receipt and for monitoring clocks.

22. Explain about Logic analyzer.

It is an important tool for debugging software

particularly embedded real time systems.

It is used to capture data or event to measure individual

instruction times, or to time section of code.

23. What is patching?

The process of correcting errors in the code directly on the

target machine is called patching.

24. Define inline patch and oversized patch.

Inline patch: If the patch needed fits into the memory space

accorded to the code to be changed, then it is considered an inline

patch.

Oversized patch: If the patch requires more memory than is

currently occupied by the code to be replaced, it is considered an

oversized patch.

25. What is SAGE?

SAGE stands for Air force’s Semiautomatic Ground

Environment.

SAGE was the first real time application developed by

whirlwind team.

26. What is the use of Real-time database?

Real-time databases are used in a variety of applications,

including process control, radar systems, computer integrated

manufacturing, traffic control, virtual reality and multimedia.

27. What are the steps involved to design a real-time databases?

Designing real-time databases involves

Analyzing the system requirements to identify data.

Determining the hardware capabilities

Identifying the different data criticalities and integrity

constraints.

28. Define virtual reality.

Virtual reality systems are complex computer simulations

involving visual, audio, tactile and other feedback to entice a

person’s perceptual mechanisms into believing they are actually in

an artificial world.

29. What are the paradigms in virtual reality?

There are three paradigms in virtual reality. They are

Telepresence

Immersion

Augmented real.

PART-B

1. Discuss in detail about multiprocessing systems.

2. Explain about Non-Von Neumann Architecture.

3. Explain the goals of real-time system Integration.

4. What are the tools available in real-time systems? Explain it.

5. Discuss in detail about Real time applications.

6. Discuss in detail about virtual reality.

7. Explain about Real-time Databases.

8. Explain about Real-time UNIX.

9. Explain in detail about the languages developed to handle real-time

applications. Explain it.

PART-C

1. Explain in detail about the multiprocessing system.

2. Explain about Distributed System.

3. Explain the Real-time applications.

4. Explain about software and hardware integration.