1. Project
-> HFS
-> SFS
-> Role & Responsibility
2. Networking
###OSI Layers###
->layer 1 and 1.5
->layer 2 , ARP, STP,VLAN,Tagging,CDP,
->layer 3, IPv4/v6, ICMP, IGMP, Routing protocol
RIP,OSPF,BGP,VPN, VRRP,
->layer 5, TCP,UDP
->layer 7, SNMP,DHCP,FTP,TFTP,
->packet flow, subnet, broadcast domain , collision
domain, wireshark, tcpdump, port channel,
load balancing,telnet,ssh,
3.OS
-> Process management
-> file mangment
-> memory mangement
-> IPC
4.C
->Bitwise operators
->size of union/structure
5.DS
->Trees
->linked list
->Hashing
->sorting
6.Interview/ Tricky questions.
->sed
->grep,egrep, vim commands,gdb,disassemble*, symbol
table, stack with arguments memory,
Suggested:
-> Hackerrank
GOAL:
->CCNA,Linux.
Links:
=====
Company: verifyx technologies
1). How to extern a below variable.
Static int a = 10;
Ans.extern int a = 10;
//extern static int a = 10;
//error: multiple storage classes in declaration specifiers
2). Show mac address CLI output?
Vlan mac-address type port
Switch has 48 ports, will it get 48 entry’s ?
Ans.
https://learningnetwork.cisco.com/s/question/0D53i00000KsyzN/about-the-command-show-mac-addresstable
SW6#sh mac address-table
Mac Address Table
-------------------------------------------.
Vlan Mac Address Type Ports
---- ----------- -------- -----
All 0011.9297.ef00 STATIC CPU
All 0011.9297.ef01 STATIC CPU
All 0011.9297.ef02 STATIC CPU
3). Int a = 10;
Char *p = &a;
Print *p == ?
Ans. ‘\n’
4).can arp go to another vlan?
5).TCP/IP round trip time calcaulation?
6).where extern and static variables are stored, scoping ?
NOTE: BSS -- uninitialized data
Data -- Initialized data
7).which IPC messages (shared memory) are you used in your project?
8).what is your role in your project?
9).what project you are working?
VVDN Technologies, kochin
q).Where static variables are stored?
q).why structure padding ? how to avoid it ?
q).how can i copy 10byte of string to char a[10] ?
if not How to make it possible?
q).how can i store 25 byte character string into char *p = malloc(10) ?
If any challanges, what are they? How do we fix it ?
NOTE:strncpy
q).how do you store pointer to a int variable ?
Is it right one?
If yes, how do we access pointer address from int?
*q).in f1, we declare structure variable sv , if we pass sv to f2 how do we
Access sv in f2 to print sv data ?
q).can we pass structure variable to another function?
q).if i open mulitple google tabs in my web browser, how each tabs will
Work well particular to their individual search ?
q).server socket programming system calls? Sequence? Arguments ?
q).How to create multi threaded server programm?
q).what is the return type of fork ?
q).what is the stack size of your linux machine / linux process / thread?
ans.The process main thread stack size cannot grow larger than the set limit. The default value of this limit is 8 MB. Exceeding this limit will result in a segmentation fault and the process will be sent a SIGSEGV signal, by default killing it.
prashad@prashad-VirtualBox:~$ ulimit -a
stack size (kbytes, -s) 8192
prashad@prashad-VirtualBox:~$
q).how pthread_create works? Arguments? Who wil fill tid arg ?
ans).
int pthread_create(pthread_t *thread, const pthread_attr_t *attr,
void *(*start_routine) (void *), void *arg);
Tricky question:
------------------
q). What is the output of below program ?
#include<stdio.h>
#include<time.h>
char timestr_1[128]="\0";
char *time_con(time_t stamp) {
struct tm *t;
t = localtime(&stamp);
strftime(timestr_1, sizeof(timestr_1),"%s", t);
return timestr_1;
}
void main() {
time_t last, first;
while(1) {
first = time(NULL);
sleep(1);
last = time(NULL);
//printf("%ld\t%ld\n", first, last);
printf("%s\t%s\n",time_con(first),time_con(last));
//printf("%s\n",time_con(last));
sleep(1);
}
}
Aricent interview questions:
1.how to pass arguments between two threads in a single process ?
2.what is the mac address for multicast?
ans.
3.ARP working whole ? arp cache ?
4.Mac table ?
Ans. vlan mac_address type ports
2 aaxxxxxxxx gi0/1
5.how many mac address switch will have ?
6.unions vs structures ?
7.where we are using unions in networking ?
8.What is the purpose of LE and BE?
9.What is the purpose of padding.
10.
Arcient interview
date:28/08/19
Interviewr: samuel
1.find a size of structure without sizeof operator
Ans.
Struct emp {
Int emp_id;
Char em[_name[10];
};
(((struct emp *)(&e+1)) - ((struct emp *) &e)) ); ⇒ 1
(((char *)(&e+1)) - ((char *) &e)) ); ⇒ 16
2.how will free() work?
3.if i given hexa dump data, how your find vlan tag is there or not?
4.purpose of double pointer?
5.where we use unions/bitfields in your project ?
6.do you know ip classes ?
7.find out loop in linked list?
8.Write a program to count number of set bits in negative number, size independent
Ans.
gdb) p/t -10
$3 = 1111 1111 1111 1111 1111 1111 1111 0110
(gdb) p/t 10
$4 = 1010
9.What are all shared between two threads?
ans). Heap, data, text, ofdt
10.Write a program to corrupt stack
11.Where were using signalling mechanisum
12.How to pass signals between two threads?
13.Sso time in HA stacking ?
Ans. 6 minutes
14.what is Preimptiev schedule in algorithm.
15.What happen to child process, if I kill parent process?
16.Why padding, what if padding not there.
17.do you know function pointers, where do you use?
18.orphan process, zombie process ?
19.explain about your critical Bug fix in your project ?
20.socket system calls in client server interaction
21.lisp protocol
22.how communication happen, suppose if standby needs to update to the
Active about linkflap.
23.
Gigamon Interview Question:
Round 1:
About project
How refer global variable in local context already defined same name in local?
Static variable access
Memory map?
About data structure
Hash concept
Round 2.
About project
Set particul
WIPRO
-----
1)What is the boot sequeuce in the board
2)What are all the process comes up
3)What are all the memory leak bugs you handled
4)What is gdb, what are all command you used.
5)How to use live gdb
6)write a program to allocate memory for three dimensional array
int ***array = malloc(3*sizeof(int**));
7)Write a program to revers linked list
8)Write a program to find, the give Tree is BST or not
===================================================================================================================
TECHNICOLOR
-----------
1)unsigned func(){
if(error)
return -1;
}
2)Memory allocation, if failure happens, we will free the memory but we dont return,
next line will have strcpy even after failure
3)circular queue logic, print used bytes between read end and write end
4)strcpy for low memory allocated buffer for ex
char arr[10]
char arr1[8]
strcpy(arr, "audiopath");
strcpy(arr1, "Myvideopath");
5)Write a program to dynamically print array 3X3
6)Write a program to get maximum of two number in the given array
7)Write a recursive program to print -5 to +5
===================================================================================================================
NOKIA
-----
1)where does IOS run, i said RAM, he said that is generic answer
2)What is SFP, what is inside in it
3)how will control phy from asic (ans MDIO), what is the line name between phy and port (ans XFI, QSGMII)
4)Write a program to do merge sort linked list
===================================================================================================================
MICROCHIP
---------
1)How ping works
2)How traffic flows in Vlan for Front side stacking
3)How packet flows from one switch to switch in stacking
4)String copy question using malloc, similar to strdup
===================================================================================================================
MBIT
----
1)What is semaphore and mutex
2)what is task and thread
3)how to synchronize thread
ans). Mutex, read-write locks, conditional variables..
4)what do you think about mbit
5)Binary search for sorted arry
6)Write a program to reverse bits (user might also give how many to shift i.e he might give 3 shift, only that should go to msb)
a=11001011
output should be 11010011
7)funca(){
int *ptr;
ptr = malloc(1);
funcb(ptr);
printf("ptr value %d", *ptr);
}
8)funcb(int *ptr){
*ptr = 5;
}
===================================================================================================================
IPINFUSION
----------
1)arr a[10]=20;
2)void *ptr; ptr++;
3)double pointer to two dimensional memory
===================================================================================================================
HPE
---
1)STP
2)Trinary search
3)Circular linked list middle node delete
4)Reverse linked list
5)OS memory management
6)Tree node Deletion
7)Stack implementation using linked list or array
8)How to find start of each memory segment
9)Semaphore and Mutex difference
10)Deadlock
11)Swap two nodes of Linked list not data
12)Malloc for 2 dimensional array
13)Null pointer crash
14)#include <stdio.h>
// A structure without forced alignment
struct test1
{
unsigned int x: 5;
unsigned int y: 8;
};
// A structure with forced alignment
struct test2
{
unsigned int x: 5;
unsigned int: 0;
unsigned int y: 8;
};
int main()
{
printf("Size of test1 is %d bytes\n", sizeof(struct test1));
printf("Size of test2 is %d bytes\n", sizeof(struct test2));
return 0;
}
un on IDE
Output:
Size of test1 is 4 bytes
Size of test2 is 8 bytes
15)#include "stdio.h"
int main()
{
struct {int i; char c;} myVar = {.c ='A',.i = 100};
printf("%d %c",myVar.i, myVar.c);
return 0;
}
Ans: 100,A
16)#include <stdio.h>
#include <sys/types.h>
int main()
{
fork();
fork();
fork();
printf("hello\n");
return 0;
}
17)Your own sizeof operator
18)Reverse linked list using recursion
19)How to check Big endian , little endian
20)Binary tree, avl tre
21)Binary tree vs linked list
22)Extern
23)Why global variable TThas default value but not local variable
24)Given linked list , create two linked list one having even place element and other having odd place elements
25)Dynamic linking, static linking
26)Multiply two number using bitwise operator
27)Compilation steps.
28)Mutex semaphore
ETC....
===================================================================================================================
HARMAN
------
1)int main()
{
char *c = "Hello";
func(c);
printf("%s", c);
}
2)func (char *c)
{
c = malloc(5);
strcpy(c,"world");
}
3)reverse all bits
4)swap nibbles in bytes
5)swap two bits
6)What is process and thread
7)semaphore and mutex
8)do you know device drivers
9)interrupt context vs process context
10What is message queue
===================================================================================================================
CAMBIUMN
--------
1)Write a short C program which prints out all of the subsets
of the numbers in the range 1..23 which add up to 23
ubsets should be printed one per line with a single space
between each number. Each subset should be free of duplicates
One of the subsets might look like this:
1 2 4 16
===================================================================================================================
HCL
---
1) Introduce Yours self
2) How many % you give strong in 'c'
3) progam write
1) char ptr[] = "abcdabrtabvbab.....";
wtite How many times "ab " in the string and the
position of the the substring "ab"
2) write program for "BIT Reverse"
3) Linked List
(i) Travserse the single List and Display them
(ii) Insert at Last
4) Declare pointer to an arrays and array of pointers
5) write progarm for pointer to an arrays to point 1D arrays
6) How to dynamically allocate 2D Array using pointer to
an array and array of pointers
7) Declare pointer to functions and where you used in project
8) what is system call?
9) what is threading?
10) How to create the thread write syntax
11) what are the problems using threads
12) what is user space and kernel space ? tell there difference
13) initial stage of process
14) what is malloc,calloc and realloc? difference, and
progarm for using realloc
15) int * ptr = NULL;
int i = 0;
ptr = (int *) malloc (20) ;
for (; i < 4; ++i) {
*ptr = i+10;
++ptr;
}
free(ptr);
The above program working or not, what is your observation.
16) what is memory leak? how to find it
17) progarm Reverse the Linked List
18) segments in memory
19) program for pointer to function ?
20) Tell me Your project with skeleton structures
II round:
1) Tell me your project
2) program for pointer to function
3) how to use gdb
4) asking in my Layer 4 in project
5) difference b/w IPV4 and IPV6
======================================================================================
NISSON & HCL
---------
1)String Concepts:
Examples : strrev,strstr,strcpy,strlen,strcmp,(write a own function)
2)Data Structure :
1)Reverse a singly and doubly link list
2)Remove a duplicate node in list
3)insert a node in singly and doubly list
3)write a own function for memcpy and memcmp and memmove
4)to set a particular bit
5)to reset a particular bit
6)reverse a bit
7)sorting programs,
1)Insertion sort, selection sort like that
2)linear search, Binary search programs
8)Delete a particular node in singly and doubly link list.
9)Reverse a bits in integer.
10)Count a number of set bits.
11)write a own function for atoi and atof
12)Basic programs also
fib,factorial etc.
13)OS Concepts:
14)Diff BW process and threads,
15)fork()
16)what is a thread
-context switching
-inter process communication
-preemptive and non preemptive process
========================================================================================
CORNET
-------
1. Sock_Dgram uses Protocol
A. Ipv4, b,Ipv6
2 . void main(){
Fork(); fork();
Print(“hello”);
}
How many times print?
3.In Preprocessing which extension create a. .a, b. .i, c. .c
4. In compilicated declaration char *arr[3]; how to tell?
5.int **p;
P= (int **) malloc(5);
How to free p?
6.malloc return NULL or 0?
7.void main(){
Main();
}
Execution time which occur?
6. union val{
Int a;
Int b;
}v;
v.a =10;
v.b=20;
print the val of v.b?
8. char *p = hello;
Increment p; print the val of p?
9. What will be output if you will compile and execute the following c code?
#define x 5+2
void main(){
int i;
i=x*x*x;/* 5+2 * 5+2 * 5+2 */
printf("%d",i);
}
(A) 343
(B) 27
(C) 133
(D) Compiler error
(E) None of above
Answer : 27
10. What will be output if you will compile and execute the following ccode?
#define call(x,y) x##y
void main()
{
int x=5,y=10,xy=20;
printf("%d",xy+call(x,y));
}
(A) 35
(B) 510
(C) 15
(D) 40
(E) None of above
Answer : 40
11. int **P;
Print (sizeof(P));
Answer : P occupies 4 bytes (in 32 bit OS) or 8 bytes (in 64 bit OS)
12. in 64 bit, how many allocate for int?
13. how to handle the signal
A. signal, b.sigaction
14. IN ctrl z Press which signal appear
15. which signal not handle ?
a. kill , b.sigalram
16.which system call create new Process?
a. Clone , b.exec
17. In file stored in unix
a. block b. Inode
18.In enum Sunday 0 tues 5 fri 7 what come for sat?
19.In bubble sort feghijl how to sort?
20.IN push 1, 2, Pop 2 push 1, 2 pop 1, 2 push 2 pop 2 pop the value is
21.2, 1, 5, 4, 3 how to sort the bubble?
22. 17 left small value right big value which sort?
23.In thread, how many segment use?
24.IN mov, add which use a. op code b. c
25.assembly convert machine code
a. compiler b.interpreter
====================================================================================================================
OTHERS
------
1.file reverse
2.storage class specifiers
3.single and double link list
4.int main()
{
char str[20]="hellow";
char *const p = str;
*p = 'M';
printf("%s\n",str);
return 0;
}
5.typedef int *ptr;
ptr p1,p2;
6.enum
7.void main()
{
int i=5;
int *ptr = &i;
int *pptr = &ptr;
printf("%p%p%d\n",ptr,*pptr+1,*ptr+1);
}
8.how will you free
#define MAXROW 3
int main()
{
int **P,i,j;
p = (int **)malloc(sizeof(int p));
reuturn(0);
}
9.tcp/ip ?
10.system call?
11.tree traversal EACKFHDBG
12.bineary trea search
13.IPV6
14.Output
int main()
{
char *arr[2] = {"HELLO","BYE"};
printf("%s\n",arr[0]+1);
return 0;
}
Technicolour written test questions:
====================================
SNIPPET 1
Find 2 logical errors in the below code snippet
Searches in “table” for “index” matching “key” and returns the corresponding data
Typedef struct {
Int index;
Int data;
}item;
Int getdata(item * table , int key)
{
Int i ;
For (i =0; i< sizeof(item); i++)
{
if(table[i].index == key) break;
}
Return table[i].data;
}
Int main()
{
Item maptable[] = {{1,10},{2,20},{3,30},{4,40}};
printf(“Value of data for index %d = %d\n”, 2, getdata(maptable,2));
}
SNIPPET 2
#define Error(str) printf(“Error %s\n”, str); exit(1);
Int main()
{
Int fd;
Char str[20] = “Hello Test me”;
if(fd = open(“xx”, O_CREAT | O_RDWR)) < 0)
Error(“open failed”);
if(write(fd, str, strlen(str) < 0)
Error(“write failed”);
if(read(fd, str, strlen(str)) < 0)
printf(“file read %s”, str);
close(fd);
}
SNIPPET 4
Find 2 logical errors in the code snippet below
The purpose of send util_SendToUart is to translate \n to \r\n and send it to output using the uart driver. There can be more than one \n terminated line
In the input string.
Void util_SendToUart ( char *string, int len)
{
I = 0;
While (i <len)
{
For (j = 1; j <len; j++)
{
if(string[j] == ‘\n’)
Break;
}
String[j] = ‘\r’;
String[j+1] = ‘\n’;
}
write_uart(&string[j], j-i+2 }; //write function takes input string and
//number of characters
I = j+1;
}
SNIPPET 5
Try making the given code below and see what needs to be fixed to make it work.
Static void mpegt_SetMemSource(
Mpegt_Object2 mpegtObject2,
eMpegt_Processor processor,
Mpegt_Source2 *src2)
{
Pk_event * volatile event_p = NULL;
Ui8 path_Name[16];
switch(processor)
{
Case kMpget_AudioProcessor:
//create memory to audio path
sprint(pathname , “MPGET %s”, “Audio”);
pathName(strlen(pathName) - 1 ] = ‘\0’;
break;
Case kMpget_VideoProcessor:
//create memory to video path
sprint(pathname, “MPGET %s”, “MemSrc2Video”);
pathName(strlen(pathName) - 1] = ‘\0’;
break;
Default:
}
}
SNIPPET
What’s wrong ?
Uin32 parseHeader()
{
if(...)
Return -1;
Return 0;
}
Evdam main( char * string , void * data)
{
if(parseHeader(...) < 0)
{
HandleError();
}
Return OK;
}
SNIPPET 8
The purpose of the below function is to make
Mirafra
Written test
1.create stack using linked list
2. Fun {
fun();
}
Int main() {
fun();
}
Ans. stack overflow
3.Reverse digit 12345 to 54321 using bit operation ?
Ans.
For (b =0 ; a> 0 ;)
{
b = (b * 10 ) + a%10;
a = a/10;
}
3.a) why bit operation is fast ?
4.Array sorting?
5.find a loop in single linked list ? what is the order of search particular
element?
6.
Company: tata elxsi
Interviewr’s:
1.toggle a bit fun(a, position)
2.process vs threads?
3.const int a = 10 vs #define a 10
4.single linked list reverse
5.reverse a string using pointers and array?
6.compilation process/steps?
7.can we use global variables in threads?
8.linux boot process?
9.lipc vs ripc, what are ipc mechanism we have ?
10.fork vs exec ?
11.how arp works ? layer 2 or layer 3?
12.whar are the types of vlan?
13.how do you get 99the element in snmp out of 100?
Ans.
14.how do you communicate user level process to kernel level process?
15. Int main() }
printf(“TATA”);
fork(); fork(); fork();
}
Int main() }
fork(); fork(); fork();
printf(“TATA”);
}
16. If two threads trying to modify variable ‘a’ then how do you protect it?
17. If one thread changing variable a = 5 to 10. Then how other threads are
Getting notified when variable changed to 10?
18. What are all arguments in pthread_mutex_lock() ?
American megatrends pvt india limitied
Interviwer:
Write a socket programming, include header file also?, whole code?
Shared memory programming, whole code ?
Linked list loop find?
If you find the loop, you need to find the exact first node?
intention without thread and process, how can
Handle the multiple client”
NotE: select system call.
How system call working? purpose?
Fread and read.? We can read fread right rather than read?
Rotate the array with n positions?
How the data copy is happening from user to kernal mode?
L&T
Interviewr: arun,vishwanth
1.Swapping a single bit within a number
2.How you are executing set of statements before executing main?
Ans.pragma, attribute
3.structure given, how the size is expected and actual with padding?
4.why strcuture padding is implemented?
5.why we need virtual memory even we have 4GB RAM?
6.why pages are 4K sizes?
Ans.
Maxwell: if chunks are smaller size, it is difficult to manage memory management.
7.how the linux device driver working?
Ans.
Maxwell: copy_to_user() function copies data block from user space to
Kernal space.
8.how the modprobe() works ?
Maxwell: program to remove or add modules from the kernel.
9.
Company: Alcalent -lucent
1.what is software interrupt and hardware interrupt ?
2.
Company: Tata Elxi
1).Data types- static vs extern,
2).inline vs macros
3).Structure vs union, bitwise operators
4).Single Linked list swapping nodes
5).Thread vs process
6).Fork vs exec
7).
Company:Tata Elxi
Interview:
1).doublend queue implementation.
1.a) queue’s?
2).which datastrcture used to perform recursion?
Ans. stack
3).string palindrom recursion ?
4).project, rip ospf,ospf states?
5).hop count , ttl in rip context?
6).
company:Tata Elxi
1).virtual address
2).memory split
3).how to trigger timely event in a same process.
NOTE: timers
4)insert a node in sorted linked list.
company:Tata Elxi
0).Bitwise operation: setting bit, toggle, count 0 in number
1).Ll : insert node
2).String rever, substring
3).Which process takes time
4).Fork, vfork, exec, wait
5).Pthread_join
6).Vxworks scheduler
Company:tata elxi
1).count number of zero’s in a given number?
2).highest number of repitated character in a following string?
Input: “Welcome to tata elexsi”
3).swap/reverse a last two nodes in a single linked list?
4).which ipc mechanisum is fast? Why?
5).pipe vs named pipe?
6).where we use pipe’s?
ans).parent to child.
7).how you will debug if you found packet loss on interface?
8).scheduling algorithms? What are they?
9).what is timslice?
ans). Giving following opportunites to the process we can call it as time
slice - memory , cpu , i/o, network.
Time slice.
10).write a declaration of function pointers and where you were used in
Your porject?
11).macro vs inline?
12).orphan process vs zombie process?
13).how to overcome orphan and zombie process?
14).semaphore vs mutex?
15).deadlock?
16).how to overcome deadlock?
17).explain your project?
18).can we use pipes between two different process rather than parent to
Child ?
ans).i guess NO.
Company: gigamon
1. strtok
2. toggle m to n bits
3. process address space
4. structure vs union
5. tell about your project
6. Socket system calls
Company: Western Digital
Intervie
1. Introduce about myself
2. JD understanding
3. Previous project explanation
4. I2C protocol
5. RTOS
6. What are the storage classes
7. Static storage class
8. Why not initialised variable stored in bss
9. How bss set 0 to uninitialised variable
10. Can we apply to function?
11. Where the local variable is stored
12. Stack overflow, stack underflow
13. What happens in stack overflow like stack section into heap?
14. How to avoid stack overflow?
15. How free knows how many bytes to free?
16. Volatile qualifier
17. Where we use const?
18. Volatile const together for a variable?
19. Use case, Purpose of volatile const variable?
20. What is structure padding? Why we need it?
21. Inline Vs Macro
22. When we will use inline / Macro
23. Priority inversion
24. How to avoid priority inversion
25. Reentrant function
26. Priority inheritance
27. Watchdog Timer
Company : NEC Telephonic
1.which datastructure you are using in your project.
2. Array vs datastructure
3. What is the size of below structures?
Struc {
Char c;
Int i;
}
Struct {
Int i;
Char c;
};
4.how to eliminate padding ?
5.sockets system calls?, how you will replace accept system call with non-blocking system call?
ans). Select.
6.snmp
Company: NEC
1.Shared memory
2.Linked list reverse
3.Finding repeated characters in a string
4.Memory management
5.Vlan
6.Write a c program for storing mac address
7.How printf is implemented internally
8.How arp wrks
9.Cscope implementation internally
10.Dynamic memory allocation
11.Where the variables are stored in memory for shared memory
12.Arguments passed for shared memory
13.Tpid in vlan
14.What is default vlan
15.Why stack grows backward and heap grows forward
16.did fopen () and not did fclose() what will happen ?
17.gdb and btdecode what content the crash log will contain in both case
memory leak
18.then about project explain a traffic drop bug
19.then explain about any protocol issue
Company:gigamon
in gigamon
1st round :
1.project software level explanation on how xcvr works
2.about memory segments
3.what is used to commnicate between cpu to asic and asic to phy
4.which ipc we are using
5.socket and program
2nd round:
1.what will happen after giving gcc a.c ---- inside
2.how a.out is getting the output explain internal process and what will linux
do after giving a.out
3.after fork doing multithread, am having int a; in parent whether this
variable will copy in fork ?
4.If not what is the way to access the same variable in parent from fork
5.Then asked about Hardware arc
NEC F2F
Cumulative questions of all interviews
1.where Shared memory will attach in process address space and why?
What are the system calls you used to attach and how?
2.Linked list reverse
3.write a program to add a node in circular linked list
4.Finding repeated characters in a string
5.How printf is implemented internally
6.Memory management
7.write Vlan header and expain each bit
What is Tpid?
What is default vlan?
Can vlan 0 exists?
What is the max vlan num?
Any other vlan’s you know?
NOTE: intention is other than 802.1q vlan whether you worked.
8.How arp works
9.Cscope implementation internally
10.Dynamic memory allocation.
11.write a function for array of pointers and assign each and explain how
It works?
12.*c[] = “Welcome to NEC”;
What is the output of *--++c+1 ?
13.Where the variables are stored in memory for shared memory?
Arguments passed for shared memory
14.Why stack grows backward and heap grows forward
Siiyer: If stack goes backward heap goes forward viceversa.
15.Makefile.
16.Touched all IPC mechanisms.
17.scheduling algorithms
18.Difference between process and thread how it will store in memory segment
19.Find whether is bit set in given position if set then do reset that bit.
20.char c = 128;
c>>2 ?
How you make not to come one’s while we right shifting a variable?
21.More questions in project on how Asic and phy communicates, phy to xcvr
Communication?
22.Spanning Tree protocol?
23.How phy knows an sfp inserted
24.How to access the variable which is defined as void pointer?
Where we use void pointers?
25.what is dangling pointer ?
26.where you used volatile in your code ?
27.MACRO vs Inline?
28.what is the size of below structures?
struct {
Char c;
Int i;
}
Struct {
Short s;
Char c;
Int i;
}
Struct {
Char c;
Int i;
Short s;
}
29.what is padding? What are all the ways to eliminate?
30.write function pointer declaration? Where you used in your code?
31.Software arch of our project?
32.
Char *a="hello"
Char *b="world"
Strcat(a,b);
Printf("%d%d",a,b);
what will be the output
33.Question on *p++ and ++*p
34.In Memory map where shared mem variables store?
35.what is the purpose of socket ?
If i have 3 process in my device, in what way we will communicatie to
Each other?
36.what is daemon process?
37.how to toggle particular bit in a variable?
38.do you know trees?
39.string reverse program?
40.do you use valgrind?
41.explain process address space diagram completely?
42.fopen vs popen?
43.how fork() will work?
44.what FILE* contain?
45.what is inode?
46.what is kernel stack and user stack?
47.what is purpose of multithreading?
48.how you will use variable length array?
49. Int index = -1;
Char c[index];
Whether program compile ?
Company: sanmina,Tambaram
1. Count set bits program?
2.why padding in structure? How do you eliminate?
What if i put #pragma pack(2)
In below structure?
Struct {
Int i;
Char c;
Float f;
}
3.LE programm?
4.how do you find number of children in a particular process?
NOTE: ps command with options as linux command.
Are there any options?
5.which sockets you are used?
6.how do you communicate between threads?
HINT: interviewer told we can use message queues between threads.
7.where we use function pointers?
8.linked list loop?
9.ISR function working?
10.how do you handle interrupts?
11.what is interrupt latency?
12.if you handling one interrupt, meanwhile another interrupt comes how you
Will handle?
13.how do you design ISR’s?
14.describe pthread_create behaviour and arguments?
15.what is the priority of newly created thread?
16.how do you use static variable in another file?
17.what is volatile? Can i put const volatile a = 10; ?
18.how do you choose IPC mechanism?
19.what are the states of process?
20.fork ?
21.process vs threads?
22.why we are going threads?
23.how do you find state of a process?
24.how do you implement multithreaded server?
25.how do you debug/handle crash?
26.gdb steps?
27.how do you handle release bugs, if your timeline comes closure?
28.what if you are not able to repro issue in locally but issue observed
In customer network?
29.how do you confirm your fix not causing any trouble for other products?
30.what are the steps you followed when you got assigned with bug?
31.explain about your project?
Company: Aricent
Interviewee: BR
1.Explain DHCP full flow.?
2.What is dhcp relay and if two relay’s are there in topology what is the flow.?
3.What are all the header fields will change from dhcp client to server flow.?
4.How do you use two threads which communicates your dhcp structures.?
5.What is the other way than locking.? (Atomic variable.)
6.ospf flow.?
7.how do you debug when you get a issue from customer?
8.can we use unions in your dhcp structure?
9.int *ptr = 10; tell about this.?
10. int a[] = {10,20,30} ; int *p = a; values of ++*p; *p++;
11.write a recursive functions to find sum of number between 4 to 8?
12 implement the memmove().?
13 how do you find loop in a linked list.?
14 how do find memleak.?
15 question about display command in hdb.?
16 write logic to delete node in linked list(take care of all the possible conditions).
17 when will the mem created for structure?
Company: comcast
=====================
1.how first time ping works?
2.mutex ki semaphores ki difference
3.Linux system calls internal functionality?
4.comcast is more about linux
5.IPC and linux commands
6.shell scripting expect cheyochu
VP round
1.C, Networking, Linux, Embedded basics
2.meru btech ECE background ayite Embedded aduguthundi
3.manaki teliste chepochu ledante ledhani chepochu, just confidence check
chestundi
4.process states, compilation process.
5.generic questions kuda adugutharu
nakaite neku edho power vachesi HCL gurinchi edina jaragalante em Jaragalanukuntav ani adigaru
Company:comcast
1st round:
1.priority inversion
2.priority inheritance
3.priority ceiling
4.interrupt latency
5.process vs threads
6.why thread is lightweight ?
7.explain IPC mechanisum?
8.array of pointers?
9.declare 2D array?
10.declare function pointers?
11.int a = 10;
Int *p = &a;
++*p = ?
12.why padding? How you will eliminate?
13.set a bit?
14.pointer to an array vs array of pointers
15.
Networking:
1.how ping works ?
2.what happen when you enter url in your browser?
3.how ping utility escapes all L7,6,5,4 headers?
4.arp and proxy arp?
5.what is LSRR?
Manager round:
1.process vs threads
2.how “cat file.txt” works?
3.write multithreaded program to print 1 2 3 4 5 6 …
Eventhread should print even numbers and odd thread should print odd numbers
NOTE: using conditional variable?
4.difference between mutes vs semaphore?
5.which sockets are you using in your project?
6.how fork works?
7.
VP round:
1.What is your strength
2.What is your weakness
3.When you will happy
4.When you will sad
5.Tell about your family
6.How you will choose ipc mechanism
7.How cat command works internally
8.Explain how you will fix CFD
9.Do you have any offer
10.How much you are expecting CTC ?
11.Comcast standard
12.What ipc will use in your project
company:Comcast
1)program to find the system is little endian or big endian
2)unsigned long size in 32 bit -- what s the logic to store 64 bit data in
long ... take userdefined data type
char a = 250
char b = 255
3)program to swap num without using third var
4)thread program using mutexes and conditional var
5)define a single macro that clear the bit at given position
6)set bit at given position
7)reverse of linked list and explanation on it
8)diff b/w mutexes and threads
9)how we can find memory in linux
10)at are the types of shell in linux --- (bash,csh..etc)
11)define a fun to swap numbers and call that fun from main values before swap
and after swap in main fun
Gigamon:
----
Candidate: BR.
1st Round:
-----
1. Write a API to swap first and last bytes in a 4byte number?
2. Write a API to find the no of set bits in a given number?
3. how to you find loop in a linked list, write code.?
4. what IPC mechanisms you know.?
5. how do you communicate in threads.?
6. what are related processes.?
7. what is semaphore write how do you use it to synchronise.?
7. are Mutex and semaphore same.?
few more on C
2nd Round:
-----
1. Brief me about your self ?
2. Given a pointer to a node how will you add new node before the given pointer consider no header is given.?
3. Write a program to convert little to bigendian.?
4. how will you choose which IPC to use.?
5. Why sharedmemory better.? (as I said)
6. write a Macro to find the square of the given number or Epxression.
Discussion on Each answer Given or written.
3rd Round:
-------
1.
NUM O/P
1 1,1
2 1,2
3 1,3
4 1,4
5 2,1
6 2,2
7 2,3
8 2,4
9 3,1
10 3,2
11 3,3
12 3,4
13 4,1
... .... and so on ...
write a program which prints the outouts for the given number. Only number is given, shoud not take any array or list. need to print with logic.?
2. Program to know the no of clear bits in a given number.
3. How do you find the sizeof structure without sizeof(). Then discusion on padding and other stuff.
4. Given a position of the node, add a new node after the position.?
5. in file 1 static int a ; in file 2 extern int a ;
will this work?
why it won't work?
when will we get this error.?
how does complires know that it is not valid.?
6. char *a = "Gigamon";
char a[7] = "Gigamon"; what are these.? is both same ? what is the difference.?
7. What is DHCP, How does it works..? what is that you did in DHCP.? isn't DHCP opensource..?
8. what is STP, how does it works ..?
9. What is ARP.? Explian Working..?
10. How Many VLANs we can have in a switch.? What is the sizeof VLAN-ID.?
11. Why are you looking for a change..?
4th Round:
—----------
Managerial:
-----------
1. Brief me about yourself.
2. how is your workflow in your current job.?
3. What type work you do.?
4. what are the best moments in you work creer.?
5. write a code to print -5 to 5 using recursion..? after writing .. can you reduces the number of recursive calls.?
6. Explain me about your products.?
7. where does your products used.?
8. what is IoT.?
9. In my office I am connected with all my devices... Is it also a IoT.?
10.What is the challenging work you did.?
11.Why do you feel it has challenging.?
12.what skillset does a sustenenance engineer need.?
13.what skillset does a developer need.?
14.If a newbie is coming to IT what piece of advice you give him to become good sustenance / Develop Engineer .?
15.what is UT.? why do you need to do UT..? Does it different than what QA team is doing.?
16.Does your code tested by QA before commiting.? if QA is testing it does UT really needed.?
17.When New enhancement comes, how will you aproach.? what informantion you will give about your work plan.?
18.Why are you looking for a change.?
19 HCL has many clinets Did you tried in them.?
20.What do you do in free time.?
Questions are mostly on what we have beed said and checking the confidence.?
Company: Aricent
-----------------
1.DHCP
2.what is interrupt?
3.signal vs interrupt?
4.how you handle interrupt?
5.function pointer purpose ?
6.any L2,L3 protocol you know/worked ?
7. Write a C program for below:
Input: “hi i am suresh from india”
Output: “hi i am from india”;
8.semaphore vs mutex difference?
9.dangling pointer.
Company: Scientific games
------------------------
1.Print odd even numbers consecutively using threads one thread odd one thread even.
2.Given a tree print left view, means u stand left side and see the tree what numbers we see print those.
3.Given a linked list how to find if there is loop
4.Abt gdb.
5.How you detect mem leak
6.Img compression techniques
7.Img standards
8.How to identify data corruption
9.Producer consumer using sockets
Company” aricent
----------------
1)Converting string MAC address to integer.
2) difference between trunk and access port and vlan the header
3) how do you know the vlan is present or not
4) how to get the IP address from DHCP
5) how to allocate the memory of two structures using one malloc
6) what is function pointer and how it is used and it declaration
7) given number is 2 power or not
8) how free know how much memory need to be free
9) how rellocate will work
10) find the loop in linked list
11) IP table, arp table, mac table
12) reverse the linked list
13) find the odd count for repeated variables in the array 1 to 100 using xor
14) difference between thread and socket
15) reverse the given number bits
16) swap n node from starting and last nodes (if 2 is given then swap 2nd and last to 2nd node)
Tech Mahindra:
Thread vs process,
what are sharing between threads and process
Fork, what are actually sharing.
Segmentation fault
Netconf
Boot process
Compilation stages
Headers vlan, ethernet, STP(spanning tree protocol)
Ip table
Reverse linked list
Merge two linked list
Two linked list, will meet at one node, what is the merge node ? whole program
Delete nth node
Set, reset bit
Int a = 1111; how many ones?
Socket, client-sever model?, argument also?
UDP Vs TCP?
-Every time UDP lo IP details passing, but not in TCP after connection established
How you know VLAN is established?
Bad pointer
Dangling pointer
-if ping www.meta.com fails,can we conclude www.meta.com is not reachable ?
(what if i can www.meta.com is still reachable/load in web browser?)
q)Will router pass/forward/route broadcast address(255.255.255.255) packet ? if no, why? If yes, in which use case?
ans). Yes in this case. When we assign/config router/switch to dhcp relay, at this scenario router forwards packet to required path to get ip address.
q).What is the mistake on 127.0.0.1 loopback address?
ans). 127.0.0.1 - comes in Class A address, hence we can’t assign 127 range address to any device, so we indirectly lost some ip’s for assigning this 127 range class A address to loopback address.
Eg: ipv4 → 127.x.x.x is a loopback address, but in ipv6 → ::1 (learnt lesson by ipv4 mistake)
Tech mahindra:
—-------------
1.thread vs process
Which is faster execution
Advantages
2.how a packet is traveled from one end to another end ?
3.how ARP works ?
4.loop logic
5.how to find last 3rd node
4.global static, how do you use ?
5.”1234” , add each one in arithmetic?
6.switch vs router
7.host to host travelling ? within same subnet/other network?
8.collison , domain?
9.core dump, how do you use in your project ? how to check structure variable ?
Gdb frame?
10.
Capgemini
—---------
1.dhcp,dns packet topologie path
2.core dump, print, frame, error,signal, backtrace.how to debug, how to root cause
3.when crash issues? - double free, dangling pointer?
4.routing tables - what are fields ?
5.Mac table
6.Forwarding table
7.gdb
8.broadcast, collision domain?
9.what happened to packet when collision occur?
10.reverse linked list, loop findout
11. M to nth bit set
12.dns uses?
13.Trees?
14.array representation?
15.ip string —-> convert to num ?
16.”123456” —> 1+2+3+4+5+6?
17. C compilation steps?
18. Mac validation ?
19. Where Malloc is stored ?
20.Hash table ?
21. Cscreen
22. Hardlink vs softlink?
23. Substring program
24.3 hosts, h1, h2 – same subnet, h3 - another subnet . h1 -> h3 , h2 -> h3 how packets flow is there ?
25.Kernel concepts
26.Context switching, uboot, file system, socket, types of socket , how to determine udp/tcp socket, where you used socket, ixigia, valgrind, spirint(Traffic generator), bridge, hub, acl(with url)., igmp, arp , dhcp , dns.
27.Firewall - how linux device ?
28.Yaml, tcpdump, iptables, netfilters.
29.unicast, broadcast,multicast - example protocols
30.vlan, trunk port, how many vlans, access port
31.strings, strrev, strcpy
32.delete DLL, add a node
33.working in hcl , how many instances of i in line of string ?
34.recent challenging bug, recent core dump.
35.
Gns
—--
4.switch vs L3 switch difference ?
5.dhcp relay?
3.
Aricent
1.dynamically create memory for 2D array.
2.what is the output ?
#include <stdio.h>
int main()
{
int arr[] = {1, 2, 3, 4, 5};
int *p = arr;
++*p;
p += 2;
printf("%d", *p); //3
printf("%d", arr[0]); //2
}
3. You need to update in same linked list
i/p linked list: head -> 9->9->9->9
p/p linked list head ->1->0->0->0->0
4. Write a function in same string
i/p - bbbcccddf o/p - f
i/p - tteddffp o/p - ep
Nokia 1st round:
1.explain how osi layer works?
2.write ethernet frame formate?
3.what is vlan, how it works? add vlan field to ethernet frame and explain?
4.write a program to add contiguous memory location for double pointer?
how to set/get data?
5.single linked list palindrome?
6.how to check two linked list's are intersect ? optimized method?
7.what is icmp, why we use icmp?
Nokia 2nd round:
1.ethernet frame + vlan formate?
2.linked list add and delete?
3.function pointer declaration with example ?
4.STP,DHCP,ICMP,ARP ?
5.how come STP knows , if it receives same packet twice ?
5.watchdog, how watchdog monitor about process died ?
6.how can you debug in case a icmp packet is received at ethernet interface,
but got failed to reach ICMP layer? how will you debug ?
7.what are the types of semaphore ?
8.what are pthread call's you know ?
9.how a process and associated 3 threads occupied in process address space ?
10.static variable in a.h, 1.c and 2.c ---> a.out, how this works?
11.what is structure size? purpose of alignment ?
typedef struct sll {
int data;
sll_t * pnext;
}
12. main()
{
register int x = 5;
int *p;
p=&x;
x++;
printf("%d",*p);
}
13. p = malloc(8).
will it allocate 8 bytes or more? how 'p' knows how many bytes allocated while
free()?
Capgenmini
1.how to generate seg fault?
2.what is wild, dangling pointer?
3.array[10] ={ 1,2,3,4,5,6,7,8,9,0}
Odd index’s - odd values
Even index’s - even values
4.create 2 threads, t1 thread and t2 thread, having global array
array[10] ={ 1,2,3,4,5,6,7,8,9,0}.
So that , t1 thread first 5 indices and t2 thread read next 5 indices, write a
Program ?
5.socket system calls?
6.
Gigamon 1st round:
—-----------------
1)reverse a bits in a num?
2)printe single occurance characters only in a input string?
i/p: dummy
o/p: duy
i/p: projectjpabcd
o/p: rojetjabd
3)reverse a double linked list?
4)how pthread's communicate ?
5)i have only address of a node which you need to delete in a single linked list.
how do you delete ?
1->2->3->4->5
0x400
Date
wipro
-----
1)int a[]={1,2,3,4,,5};
printf("%d, %d, %d, %d\n",a,a+1,&a,&a+1);
2)int *p = 1000;
printf("%d, %d, %d\n",p,&p,*p);
3)func_a(int *a) {
a = malloc(sizeof(int));
*a=10;
}
main(){
int *a
func_a(a);
printf("%d", *a);
}
4)char c;
for (c=0;c<200;c++)
printf("%d ",c);
5)char arr[]="123abc27de1"; output => 151
6)in linked list head-> 1 ->0 -> 0
print output as 100 in bitwise formate
print output as 100 as a number hundred .
7)how to check palindrome or not in single linked list ?
8)height of tree?
9)binary tree vs binary search tree ?
10)n1---router----n2 , how arp works?
Gigamaon 2nd round:
—------------------
1)
a=10, and b=20;
how a can be 10 with any operators?
int t=0;
a = a^(t=a^b);
0 0 0
0 1 1
1 0 1
1 1 0
2)strcpy and strrev
3)palindrome in linkedlist ?
i/p: 12321 or ABCBA
4)semaphore vs threads
5)how do you debug packet loss once you received at interface ?
6)how ARP and ICMP works?
7)where we use RAW socket ? purpose?
8)which IPC mechanisum you used?
9)TCP socket?
10)sockets work on kernal side ?
ans)yes, whole TCP/IP stack itself is kernal.
gigamon 3rd round:
------------------
1) create 2d array(int and char also) with 2d pointer ?
2) if n=3, reverse every 3 nodes in linked list?
3) count number of Binary 1's in a number ?
4)what will be shared across threads?
5)what IPC you used in your project?
6).what is reenterant function?
7).what is rest API?
8).what is the purpose of linux sockets? how it is different to tcp/udp sockets?
9).what is race condition?when it comes?how can you overcome?
10).how two threads do execution?
11).how you debug while logic?
12).how do you debug more memory utilization bug?
gigamon managerial
4th round:
------------------
1.explain architecuture/component of your project.
2.t1 writes a, t2 prints a, t1 writes b, t3 prints b ...
a,b,c,d,e,f,g,h,i,j .....
write a sudo code for this.
3.tell about your project.
4.how cvr/process sends to cloud?
5.what is your role?
6.why you want to move from your organization?
7.what are the enhancements you worked ?
Genesys:
1st round
---------
1.array=[9,7,6,5,4,3,2,1,0]
find range(0-7)
2.shallow copy vs deep copy?
3.polymorphism types and examples?
Vocera
1str round
----------
write a string program?, take input from stdin.
i/p: " hi how are you ? "
o/p: "hi how are you ?"
int main()
{
char s[128] = " hi how are you > ? " ;
int i =0;
int min=0,max=0;
for(i =0; i<strlen(s); i++) {
if((s[i] != ' ') && (!min)) {
min = i;
}
if((s[strlen(s)-1-i] != ' ' ) && (!max)) {
max = strlen(s)-1-i;
}
if(min && max)
break;
}
for(i = min; i<=max; i++) {
printf("%c,",s[i]);
}
}
Cyient:
—------------
1)function pointer
2)priority inversion
3)dangling pointer
4)(non)reentrant
5)deadlock
6)*p++, ++p, ++*p
Wipro
—------------
1).Char *p = “135.145.155.165”;
Write a program to find sum is ?(hint: 135+145+155+165 =600)
int main() {
// Write C code here
char *ip = "135.145.155.165"; //135+145+155+165=600
printf("Hello world");
int sum = 0;
int index = 0;
char *t = NULL;
for(int i=0; i<= strlen(ip) ; i++) {
if((ip[i] == '.') || (ip[i] == '\0')) {
t = (char *)malloc(4);
memset(t, '\0',4);
index = i;
strncpy(t,(&ip[index-3]),4);
sum = sum + atoi(t);
free(t);
t = NULL;
index = i+1;
}
}
printf("sum:%d\n",sum);
return 0;
}
Or
int main () {
char str[80] = "135.145.155.165";
const char s[2] = ".";
char *token;
int sum = 0;
/* get the first token */
token = strtok(str, s);
/* walk through other tokens */
while( token != NULL ) {
printf( "# %s\n", token );
sum = sum + atoi(token);
token = strtok(NULL, s);
}
printf("sum:%d\n",sum);
return(0);
}
2).i/p: “aBcDeF”
p/p: “AbCdEf”
Write a C program?
3)what happen if we include multiple header files in .c file?
4)tell about architecture of your project?
5)int main()
{
struct node
{
int a, b, c;
};
struct node num = {3, 5, 6};
struct node *ptr = #
printf ("%d\n", *( (int*)ptr + 1 + (1)) ); //6
// *((1000)+2) = *(10008) = 6
return 0;
}
6).structure vs union?
7). Arrays vs linked list? Which one is best?
8).count no of binary 1’s in a unsingened integer a = 16?
9).how to pass a structure to a function?
10).near pointer , far pointer?
Capgemini
—------------
1).semaphore vs mutex?
2).h1–switch/router–h2 , how ping works?
3).host/switch/router who have arp table?
4).what is snmp, how it works?
5)explain calls of TCP socket client,server model?
6)count no of binary 1’s in a num?
7)who has mac table?
8)A B C …. Z AA AB AC ….AZ BA BB BC …BZ CA CB CC ….CZ
100 101 102 126 127 …………………………
Write a c program?
9)
=================================
capgemini
1st round:
--------------
Merge two sorted linked lists
struct sll { t1
int data; 1->3->5->7->NULL
sll_t *pnext; 2->4->6->8->NULL
}sll_t; t2
sll_t * merge(sll_t *head1, sll_t *head2) {
sll_t *t1= head1,*t2 =head2;
while((t1 != NULL) && (t2 != NULL)) {
if(t1->data < t2->data) {
head3 = add_At_end(head3,t1->data);
}
else {
head3 = add_at_end(head3,t2->Data);
}
t1= t1->pnext;
t2 = t2->pnext;
}
return head3;
free_sll(head1);
free_sll(head2);
}
sll_t * add_At_end(sll_t head3, int data) {
sll_t *new = (sll_t*)malloc(sizeof(sll_t));
new->Data = data;
new->pnext = NULL;
if(head3 == NULL)
{
head3 = new;
return head3;
}
sll_T *t = head3;
while(t) {
pprev = t;
t = t->pnext;
}
if(t == NULL) {
pprev->pnext = new;
}
return head3;
}
void free_sll(sll_T*head) {
sll_T *t = head;
sll_T *pprev = NULL;
while(t) {
pprev = t;
t = t->pnext;
free(pprev);
}
head = NULL;
}
-
capgemini
2nd round:
--------------
1).
unsigned long a;
a = 0xABCD1234;
Output:
0x4BCD123A
int change(int a) {
a= (a & 0x0ffffff0) | (a & 0xf0000000)>>28 | ( a& 0x0000000f)<<28;
0x0BCD1230
4 A
}
2).
[18:51] U, Balaji
a[5] = 20;
*(a+5) = 20;
[18:51] U, Balaji
a[0][5] = 20
*((*(&a+0))+5) = 20
3).priority inversion, how you eliminate priority inversion?
4).if p1 have 4 threads, p2 has 4 threads, and having 4 processor s only, then can p1 of 4 threads can run on 4 processrs?
5).ospf vs bgp?
6).how you choose hashing or tree data structure?
7).h1-r1-r2-r3-h2, how icmp packet work?
technicolour
—-----------
1.what if two(old,new) low end devices(rpi) have the same ip, the new device is assigned the same ip statically, how will the new guy know what will happen?
2.what does a.out contain?
3.structure size {
char ,
char,
int,
float
}
4.int main() {
int i = 10;
printf("&i:%u\n",&i);
}
what if we execute a.out binary in 10 terminals at same time, can we get &i value is same?
5.diff b/w rstp vs vstp?
6.h1(vlan 100)–sw–h2(vlan 200)
h1(vlan 100)–sw–h2(vlan 100)
h1(vlan 100-Access port)–sw–h2(trunk port - vlan 200)
h1(vlan 100-Access port)–sw–h2(access port vlan 200)
h1(vlan 100-trunk port)–sw–h2(trunk port -vlan 200)
h1(vlan 100)–sw-router–h2(vlan 200) , asked scenarios of various, how packet
Goes?
7.
Max linear
—-----------
Convert string hexa number to int number? i/p: “0x1a” , o/p:26
Skbuff {
…..
Int a;
…
Int b;
}
fun(&a);
//pass a’s address , print b’s address ?
Int fun(int *data) {
//print b’s address ?
}
3.what is flooding & forwarding at switch level ?
Embeddedur
—---------
First round:
1.queue vs priority queue , any example for priority queue
2.how watchdog knows which process taking time?
3.how many set bit’s in a char ?
4.check num is power of 2 or not?
5.in class A, how many host’s we can accommodate?
6.multicast ip address range?
7.TCP 3 way handshake?
8.padding? Purpose? How can we eliminate?
9.big endian vs little endian?
10.native vlan? How many vlan?
11.are you worked on 802.3 standard?
12.binary tree vs binary search tree?
13.what actually triggers watchdog? -ans). Raise signal.
14.stack corruption? Heap corruption?
15.process vs thread?
16.process address space?
17.where static variable stored - initialized/uninitilaized?
18.#define pi 3.15
Const int pi = 3.15 , what are the differences?
19. Int main() {
https://www.google.com; //ans. Interviewer told label : https , goto
Return 0;
}
What is the behaviour, what it does?
luxoft/extreme networks/dxc
Second round
—-------------
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct val {
char char_val; //1 +3padd
int int_val;
char string_val[4096];//
void *any_val;//4 or 8
}; //5008 bytes 4+4 +4096 + 4 = 4108 , 4112
int fun(void){
printf("void");
struct val new1;
struct val new2;
memset(&new1, 0, sizeof(struct val));
memset(&new2, 0, sizeof(struct val));
if((new1.char_val == new2.char_val) && (new1.int_val == new2.int_val) &&
(strcmp(new1.string_val,new2.string_val) == 0) &&
(new1.any_val == new2.any_val)) {
printf("\nnew1 and new2 are same\n");
}
//int ret = memcmp(new1.char_val, new2.char_val,sizeof(char));
//printf("\nret:%d\n",ret)
printf("\n size of void *:%d\n",sizeof(new1.any_val));
printf("\nsize of struct val :%d\n",sizeof(struct val));
char h[] = "hello";
char *w = "world"; //
*h = 'a';//error h[0] ,*(h+0) = *h
//*w = 'a';//error
//h = w;//lvalue error
w = h;//works
return 99;
}
int main()
{
printf("Hello World");
typedef int (*n)();
n a;
a = fun;
printf("a:%d",a());
return 0;
}
Incedo
—-------------
Tcp , how secure connection happens?
Arp vs rarap ?
Flooding, aging?
How many set bits in a num?
Where we use stack’s and q’s?
Sll loop finding?
H1-router–h2 , how packet forward?
Ping works?
Dhcp, who will configure lease time?
Maxlinear
2nd round:
—------------
1.vlan frame format?
1.a) TPID vs Ethernet type field in ethernet frame?
2.proxy arp, gratuitous arp?
3.mysizeof() operator?
4.int a[8] = {2,4,6,8,-1,-10,15};
What is the least positive integer?
5.IGMP?
6.write a bit field program?
7.traceroute?
8.padding, structure size?
tejas interview questions:
--------------------------
1.how packet moves from L1 to L7 layers in skbuff context?
2.what kernal stack does?
3.what is the nth postion of bit which set's in 2^n number?
eg: 32, write a program withoug loop., hint:log function
ans).
Int i =0;
Double d = 0;
if((t=d=log2(num) && (t == d)) { // num is 2^p
printf("%d. d=%lf,t=%d\n",d, t);// t is the position of set bit.
}
4.write an iterative program, not recursive, to print nodes in tree?
5.create two dimensional array and free it.
6.what is copy-on-write ?
7.static linking vs dynamic linking?
8. What happens?
main() {
foo(a,b);
}
9.linker vs loader?
NOTE: task structure/PCB, program counter, instruction pointer,... like this
interviewer expecting while explaining loader.
10.can we write a program without main function? How to write? Do we get any
error? If any compilation error? On what stage?
Luxoft Managerial round:
—----------------------
1.why stacking functionality? People are achecving diversified model without
stacking.
2.did you worked on http?
3.
Cisco
—-----------
1.abc permutations and combinations?
2.count no of set bits in a num?
3.dhcp packets exchange?
4.how dns works?
5.reverse linked list?
6.(((45*90*27) *(23*45))/(88-25)); how it is executed? What is logic?
Hint:stack or tree
7.depth/height of a tree?
8.binary tree vs BST tree?
8.BST tree vs AVL Tree? Time complexity of BST tree?
9.traceroute utility?
10.purpose of vlan’s?
11.right shift(s) even position bits in a num?
12.depth first search?
13.accessport vs trunk port?
14.what are complexities in multithreading?
15.semaphore vs mutex?
16.anagram program?
17.how balancing happens in AVL Tree?
18.vxlan ?
Hcl
—------------
1).const int *p1;
int * const p2;
difference?
2).h1–r1-r2—---h2, how ping works?
3).ttl filed? Is there any field in ipv4 header is changing/modifying while
switching packet?
4).can we ping vlan10 to vlan20?
5).Is there any way to packet forward from vlan10 to vlan20?
6).little endian to big endian?
7).offset 3, i/p:1->2->3->4->5->6->NULL
o/p:4->5->6->1->2->3->NULL
8).how we configure ip address?
9).netstat command?
10).critical section?
11).
Infinite - nagendra
22/4
—------------------
mton bits
array even [1,2,3,4,5,6,7,8,9]
2 4 6 10 1 3 5 7 9
dhcp-imp fields
snmp - commaand ivvagane internal ga em ru avthadi
idb - hwidb, sfidb. vti- virtual tunnel interface
linked list - delete duplicate nodes
msq vs semaphore
tcp,ip,udp,arp,ike
VVDN - ravi:
======------
1.diff b/w dynamic library and static library
2.hashing method and sorting with O(n) time
3.char val=255 ; printf("val=%d\n",val);
4.how to check which function is taking most of cpu time
5.how to check memory leak
6.GDB debugging steps
7.What is the architecture used to develop an application
8.IPC mechanisms used
ACL Technologies:-ravi
=================-----
1.Packet transfer b/w one system to another system in details with TCP layers
2.What happens when we change MTU size to 30 when we whether the packet transfer and whether it is valid or not
3.L2/L3 protocol used
4.how to minimize the number of iterations to rotate the values in the linked list.
5.difference b/w sizeof and strlen
6.Hashing
7.Thread and process difference
8.types of ipc mechanisms
9.types of sockets
10.C memory layout and explanation
11.Write a program to list the words in sentence based on number of entries of each word a
Wipro - ravi
—-----------
Difference between union and structres
what happpens if I access both variables at a time from an Union
Write a program using threads
what are demon process how to implemnt them
how a demon process handles signals
explain sockets and systems calls used in sockets
explain SIP protocal and 3 way calling
what is an transaction in SIP
what are uses of writing funciton in marcto
F5
1st round & Second round:
—-------------------------
0.three threads add queue, delete queue, how to write a secure code ?
1.tcp socket calls?
2.how can tcp server fixed for n number of clients?
3.what are significant fields in TCP header?
4.how windowsize works? On what basis?
5.what is timed wait phase in TCP?
I said select, this is not he expects!
6.how do we know last updated field in union structure?
If we have 100 variables inside union structure, how can we know in run time?
7.reverse words in a sentence ?
i/p: “one two three four”
o/p: “four three two one”
8.size of structure? With sizeof operator?
9.ssl handshake, ciepher algorithms, http protocol.
10.how accept() works?why accept()? We already have master socket na ?
11.IS accept() blocking call? If yes, why it is blocking?
12.structure vs union?
13.
Truminds
—------------
1).how you monitor health of threads from main thread?
Myanswer - system(pstree) , it will list ,
Other terminal, ps command monitor.
Still he is expecting other answer.
2). How do you check folder/file size is increasing from code point view?
3).how do you check how much ram/memory usage for a process from code point view?
4).count no.of words in a sentence?
5).is_intersect(phead1,phead2);
Hcl-dell
—-------
1.how you do hashing, if file has duplicate lines?
HINT: cyclical redundancy check.
2.how to find intersection of node in two linked list?
3.if ttl=0 , what happen?
HINT: icmp error msg of respective code.
4.why gratuitous arp?
5.how select waits? How can you give no of fd’s as argument?
6.tcp 3-way handshake?
7.traceroute?
8.mirror image of tree?
9.inorder in tree?
10.BST vs AVL Tree?
11.MTU?
12.in stacking, routing tables are also synced with standby?
13.when you go iterative over recursion in trees?
14.when ‘DF’ or Do not Fragment Bit will set in IPV4 header?
15.
F5
HM round
CF round
—---------
1.what are your highs and lows in your career?
2.what is +ve and -ve?
3.did you try to improve your -ve’s?
4.Hobbies?
5.any certification done?
6.any Training completed?
7.have any chance to give presentations to your team?
8.what is your Toughest Bug?
9.
F5 - raki
Technical round -1,2
-----------------------
1) TCP- 3WHK, window size, ack, syn ack,Fin
2)how system call works, how the user data processes to kernel throughout the system calls, can you elaborate more.
3)bitwise operator - nibble reverse
4) hash table related question.
we have array[15], but having 34 numbers, how i can accommodate.
raki - collision, memory, chaining - hashing techniques
5)we have repeated array elements, how to identify unique numbers in the array.
Hint: xor technique
6)
7) duplicate elements in array, how you print in correct sequence order
A[] = {1,22,333,44,555,6};
ans: 1,2,3,4,5,6
8)linked list revers, linked list merge
9)while packet travelling from client to server, how tables populate in between
10)timestamp cookie
11)Ip layer - fragment/segmentation, offset, More fragemen bit.
how we can identify it is the last packet on fragmentation
technical round-2:
------------------
1)roman number translation program
2)A1 = { 2,2,2,3,3,4,4};
A2 = { 2,2,3,3,3,4,4,4};
how do we make these two arrays as similar/unique
HINT: delete least duplicate numbers in the array.
expected ans is A1 = A2 = {2,2,3,3,4,4}
3)client & server communication procedure
4)ips communicaiton
5)server deniel of service (DOS)
tech mahindra - ravi
—--------------------
1.realtime process vs process
2.semaphore
3.optimized strcpy ?
4.process priority - algorithms ?
5.h1-....-h2 connected, but data not able to transfer successfully, any reasons?
HINT: port filtering
6.duplicate elements in array, can you print array in correct sequence order.
7)linked list reverse, merge linked list in order.
8)how packet travelling to server, and how tables are populated in between.
9)timestamp cookie
11)ip layer - fragment/segmentation, offset, last packet, More fragment bit.
how can we determine it is the last packet in that fragment.
12)
technical round-2:
1)roman number translation program
2)A1[] = {duplicates1} = {}
A2[] = {duplicates2}. how do you remove least duplicate numbers
3)client & server communication
4) ips
5)server denial of service or DOS
ACL final round questions -
====================================
1.TCP hand shake how it happens
2.what if client doesn't respond to syn ACk
3.What if server doesn't respond for syn
4.what the flags in TCP connection
5.How does VLNs works
6.how does one VLN client communicates b\w another clients in different VLN
7.What are the differnet b/w multi thread process and multi process system
8.which approuch u will take
9.If u take tasks and implemented a multi thread process and multi process system (which is effective and why )
10.what happens one thread crashes
11.what happens one process crashes
12.what heppens if threads was using mutex locks and locked shared resource and crash what happen to other threads
13.what heppens if a shared resource used by process and lockes and process crash what heppens to other process waiting for the same process
14.Explain about hashing mechanisam
15.what are the difference between shared memory and message queues, in which cases we use them
16.who will monitor process states
17.how can u reverse a byte with out any shifing operations with time complexity as 1