The mutex (mutually exclusion) variables are used thread 
synchroniization and for protecting the shared memory(data 
segment) when multiple writes occur

The above is correct. To be more specific, a CPU might need 
to access some hardware device say I2c interface. Now if 2 
processes in running state try to acquire and use I2c for 
some data transfer, it might create problems, when one of 
them hasn't finished its operations with the device. So 
whenever some process has to make use of I2C it should lock 
upon the mutex object for I2c device. And after the 
operation gets finished it unlocks the mutex. Now some 
other process can use I2c by mutex lock.
Similarly mutex object can be used to safegaurd some other 
device resources.

ordinary OS doesnt keep any time constraints n deadlines
whereas RTOS,realtime OS keep time constrains for all
processes that it keeps track of time consumed by each event
n therefore maintains to finish tasks in specified
time..RTOS are designed n installed in systems where o/p
shud obtain in specific time..like mobile phones n all

VxWorks,QNX and some derivatives of LINUX are popular RTOS.

An RTOS is a special case of an OS. Here are few things 
which make it different.
1. The scheduler has to be pre-emptive.
2. Each task should have a priority.
3. Priority inheritance should be implemented.

write a c code.
and generate the assembly for it using
cc -S xyz.c -o xyz.S
xyz.Swill contain assembly for your c code with instructions
of the processor of your computer/hardware

www.emu8086.com
this  is the perfect site for u

You can refer www.8051projects.com...

no

NOT

Not Same

Multitasking implies time sharing, its like a single person
doing different jobs, obviously at different time slices.
Multiprocessing involves some amount of parallelism, if the
hardware supports (eg: dual core, hyper threading etc.)

not same. both are different

no both are consists of different process

CAN :- Implemented by boach
GMLAN:- Implemented for GM for vehicle network an diagnostics

in isr there is no return value but in function call there 
is return value

In function call the main program and the funtion have some 
relations but in ISR there is no need for this so there is 
no need of return value in ISR.

In case of a function call the arguments,local variables and
return address is stored in the stack where as in case of an
ISR, after executing the current instruction the context is
saved with no return value.

isr will be executed only when the system is interrupted 
whereas the function call meant for any operations to 
perform eventhough when there is no interrupt

Simply, an ISR (interrupt service routine) can be defined 
as a hardware function call. Generally, a CPU must 
immediately pay attention to a hardware interrupt call. An 
ISR is always given higher priority than a normal function 
call.

this is with reference to ARM7. The function call is made 
when cpu is in User mode(non-priveleged). 
 But an ISR is called from an Interrupt handler and cpu is 
in one of the priveleged modes. Whenever an interrupt 
occurs the control moves to a particular address in vector 
table.

regards
Achal

Here are some of the differences:
 1. Fuction call has no inputs and return args
 2. ISR is triggered by external events
 3. ISR may need special interrupt handling upon entry and  
    exit.
    i.e. IRQs masking to enable or disable interupts, 
 4. Function call and ISR stack frame are different
 5. ISR returns with an interupt return (IRET) to
    restored not only call stack context but also 
    interrupt level.

isr : is the priority oriented. all other functions are 
waiting ,to complete these routene, whenever we can call.

dont u think isr is define in particular sector of memory 
with return and all task are suspended at this time but 
function call is user define with the main program with 
return value.?

There is no comparison between function call and an ISR.
Both are used in a completely different paradigm. Hence
comparison doesn't exist.

ISR is interrupt service routine. it is seperate code 
written some where in the memory. if any  interrupt comes 
mp checks the priority of the interrupt and service it 
meanwhile the content of the progaram counter value is 
written in stack after executing isr ,execution transferred 
to main program. 
FUNCTION CALL is seperate thing. function call is seperate 
code that has to be written at the end of function . for 
example, in some programs we want to perform one operation 
repeatedly at that time we perform that operation by 
calling that function instead of writting many times.

adding to d ans-11 i wud say that....an interrupt has no 
relation with the current program or task being performed 
by the microcontroller....it is an independent task or 
program that is executed whenever the interrupt is invoked.

however, a function is a part of the program that is being 
currently executed by the microcontroller, hence it is 
local.it can be called only when the microcontroller is 
executing the program in which it is contained..or is a 
part of.

ISR has priority associate whereas function call doesn't
because of this stack structure of them are different.
If we look assembly code : function call has RET and ISR have
IRET.

In a multiplexed bus system, many devices are connected to 
a common bus. If 2 or more devices attempt to use the bus 
at the same time , then data will be lost. Thus only one 
one device must be allowed to use the bus at a time. O e 
method is to connect the devices through tri-state 
devices , which when disabled will effectively discoonect 
devices from the bus.

A device which has one input,one enable and one output line
 is called tri-state device,if two different devices wants a
common bus then tri-state device are essential to assign bus
to any one of them in bus orientation system.

Tristate also prevents loading effects caused by devices
connected on to the bus...
(adding to what has been written above)

yes we can create..

No,we can't

No we cannot create a table without primary key

No, we cannot

It's a combination of software and hardware Which are 
embedded by Kiel compiler.It 1s a device that do a specific 
task.

it is a combination of hardware and software to perform 
desired task

where the software is embedding into the hardware is called 
embedded. here software is embedded into haraware by using 
device programmer.

Embedded System is nothing but a combination of Hardware
with dedicated software designed for the specific application

Embedded System is one which performs one didicated task 
with dedicated hardware and software and over which user 
can not add and remove h/w and s/w. May be system hard or 
soft real time.

Embedded system means that the software provied the
intellengence to the electronic

embedded system is a combination of h/w n s/w for the 
execution of a desired task repeatedly...

pruthvi is right only to a certain extent.

In short, Embedded System gives intelligence to machines. 
Machines may be either electrical or electronic or 
mechanical or a combination of all.

Embedded system is nothing but that system using which we
can perform only one task.

Embedded system is one in which all hardware components
required for the system are implemented on a same platform.

pruthvi is right only to a certain extent.

In short, Embedded System gives intelligence to machines. 
Machines may be either electrical or electronic or 
mechanical or a combination of all.

Embedded system is a hardware with s/w embedded in it.it is 
used in RTOS so it is time constraint and conditions 
specified in it impossible to change

Embedded system means make any hardware compatible through
different software.Also a combination of 2 or more s/w + h/w
is called Emb.sys.

*the system which contains micro controller is called 
embedded sysyem.
*In the embedded system the software is mounted on hardware

" EMBEDDED SYSTEMS IS A SYSTEM THAT HAS EMBEDDED S/W N 
COMPUTER H/W, WHICH MAKES IT A SYSTEM DEDICATED 4 N 
APPLICATION(s), OR SPECIFIC PART OF AN APPLICATION OR 
PRODUCT OR A PART OF A LARGE SYSTEM"

Embedded system is the system of combination of both 
software & hardware which perform a specific task.

It is system which include hardware and software both and
Software is used to make the hardware working for specific
purpose.

es is a combination of s/w n h/w

Electronic devices that incorporate a computer(usually 
micro controller)within their implementation.

xor ax, ax
loop1:
        call foo
        inc al
        cmp ax, 10
        jb loop1

mov ro,#10h

here:
        acall fun
        inc   a1
        djnz  ro,here

org 00h
mov r0,#09
mov r1,#01
loop : acall func;    ; calling function in loop 9-0 times
       djnz r0,loop


func : inc r1 ; output will be in r1 register
       ret

end


if any thing plz mail to me laxman_balu@hotmail.com

Add the digits and check the sum. It would imply a 3-bit 
adder (max. value = 8 can be represented with three bits) 
and compare the result to 011.

3 input AND those 3 bits. No adder needed...

for serially arriving stream: 
use a 2 bit accumulator( S1 and S2) with outputs O1 and O2. 
Final Output will be Y = ~O1 . O2

For parallel, 
use combinational logic , probably priority encoder to
reduce  delay.

keep the number in A reg and ratate it 8 times if carry 
generates more than 3  it will indicate a non desired numer

step1: start
step2: mov the byte to accumulator
step3: intialize length = 0 , count = 0
step4: rotate acc. to right through carry.
step5: if carry = 1 , increment count
step6: increment length
step7: if length < 8 , goto step3
step8: if count = 3 , (do required action)
step9: end

Step 1:  Store the 8 bit value in a accumulator

Step 2:  Store 0x1 in a register0, initialize two counter  
with 0 i.e. store zero in a reg1 and reg2.

LOOP:
Step 3:  Check if AND operation between the value in
register0 and accumulator is set i.e. 1 
if yes, increment reg1 and reg2
If no, increment only reg2

step 4: Left shift the value of register0 by 1
step 5: if ( reg2 >=8), exit LOOP
                 if ( reg1 >= 3), show that 3 bit is set
        Else Go To LOOP



MOV XAR1, #Data
MOV XAR0, #0
MOV XAR2, #0

Loop:
TBIT *XAR1, #Count 
BF Loop1, NTC
INR *XAR0

Loop1:
INR *XAR2
MOV AL, *XAR1
CMP AL, #0x03
BF Loop3, EQ

MOV AL, *XAR2
CMP AL, #0x80
BF Loop, NEQ

Loop3:
EXIT

Sorry thr was a bit mistake. Corrected : 

MOV XAR1, #Data
MOV XAR0, #0
MOV XAR2, #0

Loop:
TBIT *XAR1, *XAR2 
BF Loop1, NTC
INR *XAR0

Loop1:
INR *XAR2
MOV AL, *XAR0
CMP AL, #0x03
BF Loop3, EQ

MOV AL, *XAR2
CMP AL, #0x80
BF Loop, NEQ

Loop3:
EXIT

I have modified it a bit,

MOVL XAR1, #Data
MOVL XAR0, #0x00
MOVL XAR2, #0x00

Loop:
TBIT *XAR1,#XAR2 
BF Loop1, NTC
INR AR0

Loop1:
INR AR2
MOV AL, *XAR0
CMP AL, @0x03
BF Action, EQ

MOV AL, *XAR2
CMP AL, @0x08
BF Loop, NEQ

Loop3:
EXIT

Action:

You fools...the question is to design a circuit
(hardware)..not writing a program.

Use a 8 bit parallel in serial out shift register. Use the
serial out bit to increment a counter(a 3 bit register), if
its one. After 8 shifts, compare the counter with 011b to
detect 3.

The first guy's got it write, every other answer is more 
complicated than needed. Also, we cannot use a 3-input AND 
like the second guy said b/c we are given 8 bits, not 3. A 
3-bit adder and a comparator is all you need.

bt y only 3 bit adder is used??

make a 4-bit adder/subtractor ( which can perform A+B and A-
B depending on value of bit say SUB..ie if SUB is 1 it will 
perform A+B ) now give A and B as inputs and make MSB of B 
as SUB bit.
suppose A=0110(6),B=1110(-2);so result will be A-B ie.,   
A+|B|=6-(-2)=8