SAP Basis Interview Questions and Answers

SAP BASIS Interview Questions and Answers For Freshers and Experienced. Download SAP Basis Frequently Asked Questions PDF.

1.Can you kill a Job? 

Yes - SM37 - select - kill 

2.If you have a long running Job, how do you analyse? 

Use transaction SE30. 

3.What is private mode? When does user switch to private mode? 

Private mode is a mode where the heap data is getting exclusively allocated by the user and is no more shared across the system. This happens when your extended memory is exhausted. 

4.How to uncar car/sar files in a single shot? 

on Unix:    $ for i in *.SAR; do SAPCAR -xvf $i; done 

5.Which table contains the details related to Q defined in SPAM? Is there a way to revert back the Q defined? If yes, How? 

There is a "delete" button when you define the queue. If you already started the import it's no more possible since the system will become inconsistent. 

6.What is mysap? 

It's a term for all the systems that in a contract (e. g. a MySAP business suite consist of ERP2005, CRM2005, SRM2005).

7.What is ASAP? 

It's an old term for an implementation strategy. Blueprint -> prototype -> goLive (if you want to say it in one sentence). 

8.Describe how SAP handles Memory Management? 

ST02 / ST03 In general via table buffers, you could go into the whole Work Process, roll in, roll out, heap (private) memory, etc. however just as a Unix or DBA admin would know, is you look this up when needed for the exact specifics. www.allindiajobs.in

9.Using Tcode SGEN I have generated 74% job and later I have terminated the job. I wish to start generating from where it stopped I have refreshed but to no chance nothing was done. How should I further proceed so as to complete the remaining job ?

Start SGEN again and select the same you have selected before. It will popup and ask if you want to start from scratch or generate the just the remaining. 

10.When we should use Transactional RFC ? 

A "transactional RFC" means, that either both parties agree that the data was correctly transfered - or not. There is no "half data transfer". 

11.What is osp$ mean? What if user is given with this authorisation? 

OPS$ is the mechanism the <SID>adm users uses to connect to the database. 

12.What is a developer key? and how to generate a developer key? 

The developer key is a combination of you installation number, your license key (that you get from https://linkonym.appspot.com/?http://service.sap.com/licensekey) and the user name. You need this for each person that will make changes (Dictionary or programs) in the system (allindiajobs.in).

13.How to see when were the optimizer stats last time run? We are using win2k, oracle 9, sapr/3 46c. 

Assumed DB=Oracle 
Select any table lets take MARA here but you should do the same for MSEG and few others to see whether the dates match or not.Run the following command on the command prompt  :- 
select last_analyzed from dba_tables where table_name like '%MARA%'; 
This gives you a straight answer .Else you can always fish around in DB14 for seeing when the optimzer stats were updated. 

14.I would like to know the version or name of SAP that is implemented in real time? 

This is a very generic question and really depends on what you are implementing (modules). 
The history of the "R/3" is 
3.0D Basis 300 
3.0E Basis 300 
3.0F Basis 300 
3.1H Basis 310 
3.1I Basis 310 
4.0B Basis 400 
4.5B Basis 450 
4.6C Basis 460 
4.71 Basis 6.20 
4.72 Basis 6.20 
5.00 Basis 6.40 (ECC 5.0 - Enterprise Core components) 
6.00 Basis 7.00 (ECC 6.0) - actually in RampUp 
All of those have increased business functionality and interfaces to other systems (CRM, BW etc.) 

15.How should I set priority for Printing say like user, team lead, project manager? 

There's nothing like "priority" settings for spool processes. Just define more (profile parameter rdisp/wp_no_spool) processes so people don't need to wait. 

16.What is the use of Trusted system. I know that there is no need of UID and PWD to communicate with partner system. In what situation it is good to go for Trusted system ? 

E. g. if you have an R/3 system and a BW system and don't want to maintain passwords. Same goes for CRM and a lot of other systems/applications. 

17.Why do you use DDIC user not SAP* for Support Packs and SPAM? 

Do _NOT_ use neither DDIC nor SAP* for applying support packages. Copy DDIC to a separate user and use that user to apply them

18.What is the systems configuration required to implement SAP.. i.e for production,development and QAS servers the hard disk space, RAM, Processor 

This also depends on what your are implementing, how many users will work on the system, how many records in what area are created etc. 
We need a BIG database system and an even bigger application servers. 

19.Let me know if my understanding below is correct: 

1) By default the RFC destination is synchronous 
2) Asynchronous RFC is used incase if the system initiated the RFC call no need to wait for the response before it proceeds to something else. 
Yes - that's right. (allindiajobs.in)
But keep in mind, that it's not only a technical issue whether to switch to asynchronous. The application must also be able to handle that correctly. 

20.What is the use of profile paramater ztta/roll_area?

The value specifies the size of the roll area in bytes. The roll area is one of several memory areas, which satisfies the user requests of user programs. For technical reasons, however, the first 250 KB or so of a user context are always stored in the roll area, further data 
- up to the roll area limit ztta/roll_first, 
- in the extended memory, up to the limit ztta/roll_extension or if extended memory is exhausted, then 
- again in the roll area, until the roll area is full, then 
- in the local process area, up to the limit abap/heap_area_dia or abap/heap_area_total or until the address space or the swap space is exhausted. 
Followed by termination with errors like STORAGE_PARAMETERS_WRONG_SET an error code, that points to memory bottleneck Minimum data transfer with context change; however, the increase helps to avoid problems (address space, swap space, operating system paging). 


21. Where you can check system log at OS level?

Check /usr/sap/<SID>/system/logs directory or goto SAP MMC console look for "system logs" Under SID.

22. How do you check whether a system is UNICODE system or not?

Go to ->SM51 tcode and click "Release Notes" button 
or click System->Status->check UNICODE values is YES or NO under SYSTEM DATA in SAP Easy Access page or execute command "disp+work-version" at command prompt.

23. What is LUW(logical unit of work)?

A list of steps within a tcode called logical LUW.

24.What are the common transport errors?

Return code 4 --> Imported with warnings
   -Generation of program, colomns or row missing
Return code 8 --> Imported with errors
  -Syntax error
  -Program generation error
  -Dictionary activation error or method execution error
Return code 12 --> Indicates Import Cancelled
  -Program cancelled due to job
  -Import cancelled due to object missing
  -Import cancellled due to object not active
Return code 18 --> Indicates Import Cancelled
  -Due to system down while import
  -Due to user expired during import
  -Due to insufficient roles or authorization

25. How to transport users from one client to another client?

To transport users within a system(same SID) go to tcode-->SCC1 -->give source and target client -->select profile SAP_USER --> schedule in background job execution.

Note: if you want to transport from different system(SID) means we can use SCC9 or SCC8 tcode by selecting SAP_USER profile in other terms called client copy or client refresh.

26. What is "OK" code and Tcode?

OK code is used within a program to execute a function.
Tcode is "Shortcut" which helps to run a program.

27. How to check list of tcodes within a SAP system and where to look for tcode names and program values.

  -Use tcode ST11 to view table TSTC
  -Go to SE93 tcode to view or Define a tcode

28. How we can disable the "IMPORT ALL" button on STMS tcode?

Login to DC(Domain controller) STMS-->System overview -->double click on corresponding system -->go to Transport Tool tab --> add/change parameter "NO_IMPORT_ALL" set its values 1.

29. What is different between client refresh and client copy?

Copying or over writing to existing client called as client refresh.
Copying to newly created client called client copy.

30. What is the purpose of table T000?

This table contains a list of defined clients within a system where we can maintain tcode SCC4.

31. How do you create a exceptional password list?

Use USR40 table to maintain exceptional password list.

32. What is the purpose of table USR02?

USR02 table stores user logon data like usernames, encrypted password, creation date...etc

33. How can you check/tell if a transport entry is in the process of being imported?

Check table TRBAT.

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Teradata Interview Questions and Answers

Teradata Interview Questions and Answers For Freshers and Experienced Professionals. Download Teradata Frequently Asked Questions PDF.

1. How do you define Teradata?

Ans.

Give some of the primary characteristics of the same.
Teradata is basically an RDMS which is used to drive the Datamart, Datawarehouse, OLAP, OLTP, as well as DSS Appliances of the company. Some of the primary characteristics of Teradata are given below.
Is capable of running on Single-nodes, as well as multi-nodes.
Parallelism is built into the system.
Very much compatible with the standards of ANSI.
Tends to act in the same way as a server.
It is an Open System that basically executes for UNIX MR-RAS, Suse Linux ETC, WIN2K, etc.



2. What are the newly developed features of Teradata?

Ans.

Some of the newly developed features of Teradata are: –
Automated temporal analytics
Extension in the compression capabilities which allows flexible compression of data about 20 times more data than the previous version.
Customer associated innovation like tetradata viewpoint.



3. Highlight a few of the important components of Teradata?

Ans.

Some of the important components of Teradata are: –
Bynet
Access Module Processor (AMP)
Parsing Engine (PE)
Virtual Disk (vDisk)
Virtual Storage System (VSS)



4. Mention the procedure via which, we can run Teradata jobs in a UNIX environment.

Ans.

All you have to do is perform execution in UNIX in the way as mentioned below.
$Sh > BTEQ < [Script Path] > [Logfile Path] or
$Sh > BTEQ < [Script Path] TEE [Logfile Path]



5. In Teradata, how do we Generate Sequence?

Ans.

In Teradata, we Generate Sequence by making use of Identity Column



6. During the Display time, how is the sequence generated by Teradata?

Ans.

All you have to do is use CSUM.



7. A certain load is being imposed on the table and that too, every hour. The traffic in the morning is relatively low, and that of the night is very high. As per this situation, which is the most advisable utility and how is that utility supposed to be loaded?

Ans.

The most suggestible utility here has to be Tpump.
By making use of packet size decreasing or increasing, the traffic can be easily handled.



8. If Fast Load Script fails and only the error tables are made available to you, then how will you restart?

Ans.

There are basically two ways of restarting in this case.
Making the old file to run – Make sure that you do not completely drop the error tables. Instead, try to rectify the errors that are present in the script or the file and then execute again.
Running a new file – In this process, the script is executed simply using end loading and beginning statements.
This will help in removing the lock that has been put up on the target table and might also remove the given record from the fast-log table.
Once this is done, you are free to run the whole script once again.




9. Mention a few of the ETL tools that come under Teradata.

Ans.

Some of the ETL tools which are commonly used in Teradata are DataStage, Informatica, SSIS, etc.



10. Highlight a few of the advantages that ETL tools have over TD?

Ans.

Some of the advantages that ETL tools have over TD are: –
Multiple heterogeneous destinations, as well as sources can be operated.
Debugging process is much easier with the help of ETL tools owing to full-fledged GUI support.
Components of ETL tools can be easily reused, and as a result, if there is an update to the main server, then all the corresponding applications connected to the server are updated automatically.
De-pivoting and pivoting can be easily done using ETL tools.



11. What is the meaning of Caching in Teradata?

Ans.

Caching is considered as an added advantage of using Teradata as it primarily works with the source which stays in the same order i.e. does not change on a frequent basis. At times, Cache is usually shared amongst applications.




12. How can we check the version of Teradata that we are using currently?

Ans.

Just give the command .SHOW VERSION.



13. Give a justifiable reason why Multi-load supports NUSI instead of USI?

Ans.

The index sub-table row happens to be on the same Amp in the same way as the data row in NUSI. Thus, each Amp is operated separately and in a parallel manner.



14. How is MLOAD Client System restarted after execution?

Ans.

The script has to be submitted manually so that it can easily load the data from the checkpoint that comes last.



15. How is MLOAD Teradata Server restarted after execution?

Ans.

The process is basically carried out from the last known checkpoint, and once the data has been carried out after execution of MLOAD script, the server is restarted.



16. What is meant by a node?

Ans.

A node basically is termed as an assortment of components of hardware and software. Usually a server is referred to as a node.



17. Let us say there is a file that consists of 100 records out of which we need to skip the first and the last 20 records. What will the code snippet?

Ans.

We need to use BTEQ Utility in order to do this task.
Skip 20, as well as Repeat 60 will be used in the script.



18. Explain PDE.

Ans.

PDE basically stands for Parallel Data Extension. PDE basically happens to be an interface layer of software present above the operation system and gives the database a chance to operate in a parallel milieu.



19. What is TPD?

Ans.

TPD basically stands for Trusted Parallel Database, and it basically works under PDE.
Teradata happens to be a database that primarily works under PDE.
This is the reason why Teradata is usually referred to as Trusted Parallel or Pure Parallel database.



20. What is meant by a Channel Driver?

Ans.

A channel driver is software that acts as a medium of communication between PEs and all the applications that are running on channels which are attached to the clients.



21. What is meant by Teradata Gateway?

Ans.

Just like channel driver, Teradata Gateway acts as a medium of communication between the Parse Engine and applications that are attached to network clients.
Only one Gateway is assigned per node.



22. What is meant by a Virtual Disk?

Ans.

Virtual Disk is basically a compilation of a whole array of cylinders which are physical disks. It is sometimes referred to as disk Array.



23. Explain the meaning of Amp?

Ans.

Amp basically stands for Access Module Processor and happens to be a processor working virtually and is basically used for managing a single portion of the database.
This particular portion of database cannot be shared by any other Amp.
Thus, this form of architecture is commonly referred to as shared-nothing architecture.



24. What does Amp contain and what are all the operations that it performs?

Ans.

Amp basically consists of a Database Manager Subsystem and is capable of performing the operations mentioned below.
Performing DML
Performing DDL
Implementing Aggregations and Joins.
Releasing and applying locks, etc.



25. What is meant by a Parsing Engine?

Ans.

PE happens to be a kind Vproc. Its primary function is to take SQL requests and deliver responses in SQL. It consists of a wide array of software components that are used to break SQL into various steps and then send those steps to AMPs.



26.What do you mean by parsing?

Ans.

Parsing is a process concerned with analysis of symbols of string that are either in computer language or in natural language.



27. What are the functions of a Parser?

Ans.

A Parser: –
Checks semantics errors
Checks syntactical errors
Checks object existence



28.  What is meant by a dispatcher?

Ans.

Dispatcher takes a whole collection of requests and then keeps them stored in a queue.
The same queue is being kept throughout the process in order to deliver multiple sets of responses.



29. How many sessions of MAX is PE capable of handling at a particular time?

Ans.

PE can handle a total of 120 sessions at a particular point of time.



30. Explain BYNET?

Ans.

BYNET basically serves as a medium of communication between the components.
It is primarily responsible for sending messages and also responsible for performing merging, as well as sorting operations.



31. What is meant by a Clique?

Ans.

A Clique is basically known to be an assortment of nodes that is being shared amongst common disk drives.
Presence of Clique is immensely important since it helps in avoiding node failures.



32. What happens when a node suffers a downfall?

Ans.

Whenever there is a downfall in the performance level of a node, all the corresponding Vprocs immediately migrate to a new node from the fail node in order to get all the data back from common drives.



33. List out all forms of LOCKS that are available in Teradata?

Ans.

There are basically four types of LOCKS that fall under Teradata.
These are: –
Read Lock
Access Lock
Exclusive Lock
Write Lock




34.  What is the particular designated level at which a LOCK is liable to be applied in Teradata?

Ans.

Table Level – All the rows that are present inside a table will certainly be locked.
Database Level Lock – All the objects that are present inside the database will be locked.
Row Hash Level Lock – Only those rows will be locked which are corresponding to the particular row.



35. In the Primary Index, what is the score of AMPs that are actively involved?

Ans.

Only one AMP is actively involved in a Primary Index.



36. In Teradata, what is the significance of UPSERT command?

Ans.

UPSERT basically stands for Update Else Insert.
This option is available only in Teradata.



37. Highlight the advantages of PPI(Partition Primary Index)?

Ans.

PPI is basically used for Range-based or Category-based data storage purposes.
When it comes to Range queries, there is no need of Full table scan utilization as it straightaway moves to the consequent partition thus skipping all the other partitions.



38. Give the sizes of SMALLINT, BYTEINT and INTEGER?

Ans.

SMALLINT – 2 Bytes – 16 Bites -> -32768 to 32767
BYTEINT – 1 Bytes – 8 Bits -> -128 to 127
INTEGER – 4 Bytes – 32 Bits -> -2,147,483,648 to 2,147,483,647



39. What is meant by a Least Cost Plan?

Ans.

A Least Cost Plan basically executes in less time across the shortest path.



40. Highlight the points of differences between the database and user in Teradata?

Ans.

A database is basically passive, whereas a user is active.
A database primarily stores all the objects of database, whereas a user can store any object whether that is a macro, table, view, etc.
Database does not has password while the user has to enter password.



41. Highlight the differences between Primary Key and Primary Index?

Ans.

Primary index is quite mandatory, whereas Primary Key is optional.
Primary Index has a limit of 64 tables/columns, whereas Primary Key does not have any limit.
Primary Index allows duplicates and nulls, whereas Primary Key doesn’t.
Primary Index is a physical mechanism, whereas Primary Key is purely logical mechanism.



42. Explain how spool space is used?

Ans.

Spool space in Teradata is basically used for running queries.
Out of the total space that is available in Teradata, 20% of the space is basically allocated to spool space.



43. Highlight the need for Performance Tuning?

Ans.

Performance tuning in Teradata is basically done to identify all the bottlenecks and then resolve them.



44. Comment whether bottleneck is an error or not?

Ans.

Technically, bottleneck is not a form of error, but it certainly causes a certain amount of delay in the system.



45. How can bottlenecks be identified?

Ans.

There are basically four ways of identifying a bottleneck.
These are: –
Teradata Visual Explain
Explain Request Modifier
Teradata Manager
Performance Monitor



46. What is meant by a Highest Cost Plan?

Ans.

As per Highest Cost Plan, the time taken to execute the process is more, and it takes the longest path available.



47. Highlight all the modes that are present under Confidence Level?

Ans.

Low, No, High and Join are the four modes that are present under Confidence Level.



48. Name the five phases that come under MultiLoad Utility?

Ans.

Preliminary Phase, DML Phase, Data Acquisition Phase, Application Phase and End Phase.



49. Highlight the limitations of TPUMP Utility.

Ans.

Following are the limitations of TPUMP utility: –
We cannot use SELECT statement.
Data Files cannot be concatenated.
Aggregate and Exponential operators are not supported.
Arithmetic functions cannot be supported.



50. In BTEQ, how are the session-mode parameters being set?

Ans.

set session transaction BTET -> Teradata transaction mode
set session transaction ANSI -> ANSI mode
These commands will work only when they are entered before logging into the session.

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CCNA Interview Questions and Answers

CCNA Interview Questions and Answers For Freshers and Experienced. Download CCNA Frequently Asked Questions PDF.

1. What is difference between Switch & Hub?

Ans.

Switch:
Switches operate at Layer 2 Data Link Layer
Address Learning
Forward / Filter decision using MAC address
Loop Avoidance
Breakup collision domains
Switches create separate collision domains but a single broadcast domain

Hub:
Hub operates at Layer 1 Physical Layer
No Filtering
No Addressing
Hub creates single collision domain and single broadcast domain
Make forwarding to all the ports when signal is arrived   

2. What is PING utility?

Ans.

PING – Packet Internet Gopher
A utility that verifies connections to one or more remote hosts. The ping command uses the ICMP echo request and echo reply packets to determine whether a particular IP system on a network is functional. Ping is useful for diagnosing IP network or router failures.   

3. What is a VLAN? What does VLAN provide?

Ans.

VLAN – Virtual Local Area Network
Vlan is a logical grouping or segmenting a network connected to administratively defined ports on a switch, they provide Broadcast control, Security and Flexibility.


4. What is Subnetting? Why is it used?

Ans.

Used in IP Networks to break up larger networks into smaller subnetworks. It is used to reduce network traffic, Optimized network performance, and simplify management i.e. to identify and isolate network problems.   


5. Difference between the Communication and Transmission?

Ans.

Communication is the process of sending and receiving data by means of a data cable that is connected externally.
Transmission means the transfer of data from the source to the destination.   



6. What is RAID in ccna?

Ans.

A method used to standardize and categorize fault-tolerant disk systems. RAID levels provide various mixes of performance, reliability, and cost. Some servers provide three of the RAID levels: Level 0 (striping), Level 1 (mirroring), and Level 5 (striping & parity).   



7. What are 10Base2, 10Base5 and 10BaseT Ethernet LANs?

Ans.

10Base2 an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 200 meters (185mts). Known as Thinnet.

10Base5 an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 500 meters. Known as Thicknet.

10BaseT an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses two pairs of twisted-pair baseband signaling, with a contiguous cable segment length of 100 meters.  


8. What are the two types of Transmission Technology available in ccna?

Ans.

Two types of Transmission Technology available in ccna are Point – to – Point and Broadcast   



9. What is point-to-point protocol in ccna?

Ans.

An industry standard suite of protocols for the use of point-to-point links to transport multiprotocol datagrams.   




10. What are the possible ways of data exchange in ccna?

Ans.

Possible ways of data exchange in ccna are
Simplex
Half-duplex
Full-duplex   


11. What is difference between Baseband and Broadband Transmission in ccna?

Ans.

In a baseband transmission, the entire bandwidth of the cable is consumed by a single signal.

In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.   

12. What is Protocol Data Unit in ccna?

Ans.

The processes at each layer of the OSI model.
Layers----------PDU
Transport-------Segments
Network---------Packets/Datagrams
Data Link-------Frames
Physical--------Bits   




13. What are major types of Networks and explain?

Ans.

Peer-to-Peer Network
Computers can act as both servers sharing resources and as clients using the resources.


Server-based Network
Provide centralized control of network resources and rely on server computers to provide security and network administration   




14. What is Passive Topology in ccna?

Ans.

When the computers on the network simply listen and receive the signal, they are referred to as passive because they don’t amplify the signal in any way.   




15. What is the Mesh Network?

Ans.

A network in which there are multiple network links between computers to provide multiple paths for data to travel.   




16. How network Gateway is different from Routers?

Ans.

Gateway
A device connected to multiple physical TCP/IP networks capable of routing or delivering IP packets between them.

Router
It’s a layer 3 device that connects 2 different networks and routes packets of data from one network to another. It breaks up Broadcast domain as well as Collision Domain.   




17. What is the network Brouter?

Ans.

It’s a Hybrid device that combines the features of both bridges and routers.   


18. What is the network Subnet?

Ans.

A subnet is the subdivision of an IP network.   

19. What is the Frame relay, in which layer it comes?

Ans.

Frame relay is an industry standard, shared access, switched Data Link Layer encapsulation that services multiple virtual circuits and protocols between connected mechanism.
Frame relay is a packet-switched technology.   



20. What is the Terminal Emulation, in which layer it comes?

Ans.

The use of software, installed on PC or LAN server, that allows the PC to function as if it were dumb terminal directly attached to a particular type of mainframe.
Telnet is also called as terminal emulation. It belongs to application layer.   


21. What is the Beaconing?

Ans.

An FDDI frame or Token Ring frame that points to serious problem with the ring, such as a broken cable. The beacon frame carries the address of the station thought to be down.   


22. What are the NetBIOS and NetBEUI?

Ans.

NetBIOS – Network Basic Input / Output System
An application-programming interface (API) that can be used by programs on a local area network (LAN). NetBIOS provides programs with a uniform set of commands for requesting the lower-level services required to manage names, conduct sessions, and send datagrams between nodes on a network.

NetBEUI – NetBIOS Extended User Interface
An improved version of the NetBIOS protocol, a network protocol native to Microsoft Networking. It is usually used in small, department-size local area networks (LANs) of 1 to 200 clients. It can use Token Ring source routing as its only method of routing.   


23. What is the Cladding?

Ans.

A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.


24. What is the Attenuation?

Ans.

In communication weakening or loss of signal energy, typically caused by distance.   




25. What is the MAC address?

Ans.

The address for a device as it is identified at the Media Access Control (MAC) layer in the network architecture. MAC address is usually stored in ROM on the network adapter card and is unique.




26. What is the ICMP protocol?

Ans.

ICMP – Internet Control Message Protocol
It is a Network Layer Internet protocol, which can report errors and status information. We can use the ping command to send ICMP echo request messages and record the receipt of ICMP echo reply messages. With these messages, we can detect network or host communication failures and troubleshoot common TCP/IP connectivity problems.   


27. What is the difference between ARP and RARP?

Ans.

ARP – Address Resolution Protocol
The protocol that traces IP addresses to MAC addresses.

RARP – Reverse Address Resolution Protocol
The protocol within the TCP/IP stack that maps MAC addresses to IP addresses.   




28. What is the difference between TFTP and FTP application layer protocols?

Ans.

TFTP – Trivial File Transfer Protocol
A stripped down version of FTP, easy to use and fast. TFTP has no Directory browsing, no Authentication and insecure it can only send and receive files.


FTP – File Transfer Protocol
The TCP/IP protocol used for transmitting files between network nodes. FTP allows access to both Directories and files, manipulating directories, typing file contents and copying files between hosts.   




29. Explain 5-4-3 rule?

Ans.

In a Ethernet network, between any two points on the network, there can be no more than five network segments or four repeaters, and of those five segments only three of segments can be populated.   




30. What is the MAU?

Ans.

MAU – Multistation Access Unit   


31. What is the difference between routable and non- routable protocols?

Ans.

Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router.




32. What is the logical link control?

Ans.

One of two sublayers of the data link layer of OSI reference model, as defined by the IEEE 802 standard. This sublayer is responsible for error detection but not correction, flow control and framing.


33. What is the Virtual Channel?

Ans.

A logical circuit that is created by Virtual channel links. It carries data between two endpoints in a network.

The other name for Virtual Channel is Virtual Circuit.   




34. What is the Virtual Path?

Ans.

Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path.   

35. What is the multicast routing?

Ans.

Sending a message to a group multicast address is called multicasting, and its routing algorithm is called multicast routing.   



36. What is the IGP (Interior Gateway Protocol)?

Ans.

Any protocol used by an internetwork to exchange routing data within an autonomous system. E.g. RIP, IGRP and OSPF.   




37. What is OSI?

Ans.

Open System Interconnection. t was first name of 7 Layer


38. What is the default size of Frame?

Ans.

1518 bytes   




39. Which layer are called upper layer?

Ans.

a) Application Layer - 7
b) Presentation Layer – 6
c) Session Layer – 5   


40. Tell me How many reserve ports?

Ans.

0 – 1023




41. Which decision called socket base?

Ans.

IP plus port (IP on layer 3 and port on Layer 4 – In Encapsulation, socket base decision on Network Layer -Layer 3)   





42. Do you know How many types of Data?

Ans.

Voice, video, text   




43. What is segmentation and fragmentation?

Ans.

To divide data in pieces is called segmentation and divide segmentation in pieces called Fragmentation.   


44. Which layer called error detection layer?

Ans.

Data link layer   


45. What is FCS?

Ans.

Frame Check Sequence -
CRC (Cyclic Redundancy Check) algorithm runs in switch that called FCS (Frame Check Sequence)   


46. What is Encapsulation and De-encapsulation?

Ans.

To send data called encapsulation and receive data called De-encapsulation.   


47. What is BIA?

Ans.

Burn in Address other name is MAC address




48. What is Size of IPv4 MAC Address?

Ans.

48 Bits   


49. Why MAC address called Physical address?

Ans.

Because it’s not changeable


50. Who controls MAC address uniqueness and how?

Ans.

IEEE (Institute of Electrical Electronics and Engineering) Controls its uniqueness.
They divide 48 bits MAC address in two parts. (allindiajobs.in)
First 24 bits part called OUI (Organizational unique identifier) and other 24 bits are device code.   

51. How we can see MAC address from DOS Prompt?

Ans.

ipconfig/all   




52. Why IP address called logical address?

Ans.

Private IP called logical address because they are change able.   




53. What is the size of IPV4?

Ans.

32 bits   




54. What is Syntax of IPV4?

Ans.

 DOT


55. How many types of IPS?


Ans.

Three Types of IP
1- Public
2- Private
3- Special IP   


56. What are the ranges of private IPS?

Ans.

A Class = 10.0.0.0 – 10.0.0.255
B Class = 172.16.0.0 – 172.31.0.0
C Class = 192.168.0.0 – 192.168.0.255   


57. What is the difference between bus topology and HUB?

Ans.

Hub is Centralized device ( series ) .Bus topology is Decentralized device (in parallel)   





58. Is hub intelligent device?

Ans.

No; because it not use header   


59. Which protocol switch use for filling its MAC-Table?

Ans.

ARP – Address Resolution Protocol   





60. What is CAM?

Ans.

Content Address Memory. its another name of MAC address table.   




61. Which type for communication switch do?

Ans.

In case of any new event switch do broadcast, after that always do Unicast.   





62. If line down and protocol also down; in this case which layer move problem?

Ans.

Physical Layer – Layer 1   




63. If line up, but protocol down which layer should be troubleshot?

Ans.

Data link problem – Layer 2



64. On which base switches take decisions?

Ans.

Mac Address





65. How ARP brings MAC address for switch?

Ans.

Through Broadcast   




66. How many collision domains are in switch?

Ans.

Equal number of ports   




67. How many broadcast domains are in Switch?

Ans.

One   





68. What is the subnetmask of / 27 in network based and host based?

Ans.

In network based 224 { 128+64+32}and in host based 248 (128+64+64+16+8)




69. What will be the prefix length of 224 in VLSM?

Ans.

27 (carry 3 bits from host (128+64+16=224) and add in network ports (24+3=27) )   




70. How many valid IP will b in /21 in route Summarization?

Ans.

1044   




71. In which protocol you manually enable route summarization?

Ans.

OSPF   



72. In which protocol supenetting is enable by default?

Ans.

RIPv2 and EIGRP





73. What is MAC address size of IPv6?

Ans.

64 bits




74. Default Packet Size of IPv6?

Ans.

8 Bytes = 16*8 =128 bit   




75. How many fillers we can put in one IP of IPv6?

Ans.

ONE (:: called filler)




76. Which mathematically form used inIPv6?

Ans.

Hexadecimal   




77. What is quality of IPv6?

Ans.

a) Router processing will rapid because field size wills 8 bytes (but in IPv4 it was 12 byres)

b) No Fragmentation

c) No Checksum   





78. Define Network?

Ans.

Communication, Resource sharing and Media (When multiple host share their resources with each other OR when multiple devices connect with each other for resource sharing )   




79. Explain Types of communication in IPv4?

Ans.

Unicast, Multicast and Broad cast   





80. Types of communication in IPv6 ?

Ans.

Unicast, Multicast and Anycast





81. Types of Resource Sharing?

Ans.

Intranet , Extranet and Internet .


82. What is Collision?

Ans.

When signal hits each other, collision accord.   


83. Which Type of Transmission Bus Topology Support?

Ans.

Half Duplex


84. What is the difference between half duplex and full duplex?

Ans.

In half duplex, sender should b one. In full duplex, sender can be multiple.


85. Which way of communication bus topology use?

Ans.

Broadcast   




86. If there is only 2 Host in Bus Topology is that possible collision accord?

Ans.

Yes, because end terminal will not absorb signals. Signal will be bounce back and collision will accord.   




87. HUB in Star topology or Bus Topology?

Ans.

In star topology, but logically works like a bus topology.   



88. What we called 64 Bit Mac-address in IPV6?

Ans.

EUI= Enhanced universal identifier – 16 bits add in IPv6 so it’s called EUI




89. What is loop back IP in IPV6?

Ans.

1 and ping 6


90. Which command we use for ping in IPv6?

Ans.

Ping6 source IP -s Destination IP   


91. How many types of router?

Ans.

Two types

i) Modular

ii) Non-Modular   


92. When we use Router?

Ans.

For communication between different networks




93. Which works router Do?

Ans.

1- Path selection and

2- Packet Switching {frame relay}   





94. What cable called V.35?

Ans.

Serial Connectivity cable




95. How many types of Ethernet?

Ans.

4 types

i) Ethernet

ii) Fast Ethernet

iii) Gigabit

iv) 10 Giga.   



96. Which cable called roll-over?

Ans.

Console access able


97. Which cable we connect in DB-9?

Ans.

Roll over calbe


98. How many ways to access router?

Ans.

3 ways

i) Telnet (IP)

ii) AUX (Telephone)

iii) Console (cable)   






99. What is IOS?

Ans.

Internet Operating system. Its router’s operating system.   


100. Which mode called privilege mode?

Ans.

Second mode   

Read More

Citrix Interview Questions and Answers

 Citrix interview questions and answers for freshers and experienced professionals. These Citrix FAQ's are prepared by Citrix subject experts.


1. What is ICA?

Ans.

ICA – Independent Computing Architecture:

- Application publishing is supported by ICA.

- Low bandwidth is sufficient for ICA.

- Encryption is possible I ICA.

- Keyboard and Mouse inputs are present in ICA.

- ICA ensures session reliability.   

2. What is RDP – Remote Desktop Protocol?
Ans.

RDP – Remote Desktop Protocol:

- RDP works only under TCP/IP.

- RDP does not support applications to run in a browser.

- Session reliability is not ensured by RDP.   

3. What is Citrix Access Gateway?
Ans.

- CAG is a universal Secured Socket Layer Virtual Private Network appliance.

- It is a blend of best features of IPSec and SSL VPN.

- It allows easy access to the users and secure access to company.

- Any information resource can be gained by using CAG with secure, single point access, always-on features.

- Any firewall is supported for Citrix Access Gateway.

- Supports various types of applications, including IP telephony.

- Any application that is hosted on Citrix Presentation Server can be accessed in a secured manner.

4. Explain the load evaluators are supported in Citrix?

Ans.

- CPU Utilization

- Memory Utilization

- IP Range

- Page Swap

- Page Faults

- Disk Data I/O

- Context Switches

- Scheduling

- User Application Load

- Server Application Load   


5. Do you have any idea ICA file in Citrix?

Ans.

- ICA stands for Independent Computing Architecture.

- It contains published application information.

- ICA file has Windows ‘ini’ format.

- It is organized in such a way that MetaFrame Presentation Server Clients can interpret.

- ICA file will initialize a client’s session running on the server.

- The MetaFrame Presentation Server‘s clients uses the ICA protocol for input formats and addresses the input to the server for further processing.


6. Can you explain what are the differences between ICA and RDP?
Ans.

ICA – Independent Computing Architecture:

- Application publishing is supported by ICA.

- Low bandwidth is sufficient for ICA.

- Encryption is possible I ICA.

- Keyboard and Mouse inputs are present in ICA.

- ICA ensures session reliability.

RDP – Remote Desktop Protocol:

- RDP works only under TCP/IP.

- RDP does not support applications to run in a browser.

- Session reliability is not ensured by RDP.   

7. Do you know what is the limit of refresh time for Local Host Cache in Citrix?

Ans.

- LHC refresh time is 30 minutes.
- LHC can be created when IMA is stopped.   


8. Tell me how to set the refresh time?

Ans.

- User the option "dsmaint recreatelhc" or "dsmaint refreshlhc" -> restart IMA.   

9. Can you please explain how to see the LHC information?

Ans.

- The LHC information is available in the file imalhc.mdb.
- This file is available in c:\program files\citrix\independent management architecture\ directory

10. Do you know how to implement policies to streamed applications?

Ans.

- Open the application profile with Streaming Profiler.

- Move to Target and click on Edit->Target Properties.

- Move to Rules Tab.

- Add an Ignore Registry rule that is similar to the description I CTX10352.

- The GPO’s of the domain will be applied.

- Customize GPO configuration.

11. Do you have any idea about Citrix XML broker?
Ans.

- It functions as an intermediary between the farm and Web Interface.

- XML Broker receives the credentials of user from the Web Interface.

- XML Broker retrieves the applications which have user permissions to access.

- This is done by Independent Management Architecture and returns to the Web Interface.

- Once the user is authenticated, the XML broker locates the server in the farm.

- XML Broker returns the address of the service rendering server to the Web Interface.

- XMS Service functions between Web Interface and IMA service.   


12. Tell me what is Speed Screen Latency Reduction?

Ans.

- SLR is built into MetaFrame Presentation servers and ICA client systems that provides users to experience smooth typing, where the latency is high between ICA client and the server.

- Smooth typing experience is provided while writing MS Word document, where the latency is 200 / 500 or even 1000ms of latency between them.

- Speed Screen Latency Reduction provides local text echo.

- This allows characters to be appeared on the ICA client device screen.

- After pressing a key, the ICA client sends the key press code to the server.

- The server processes the key sent, places the character into the screen buffer.

- Finally it sends the latest screen image to the client device.   


13. Please tell me what is load balancing in Citrix?

Ans.

- Load balancing is a feature that distributes client requests across servers for optimum utilization of the resources.

- In a real-time scenario, the services are provided to large number of clients from a limited number of servers.

- To reduce the load on servers, the system selects certain servers.

- These servers implements certain criteria to forward incoming requests.

- There are virtual servers that identifies the server using the load balancing criteria.

- When the client connects to the server, the virtual sersver terminates the connection and initiates a new connection with the selected server.

- The load balancing feature manages the traffic from layer 4 (TCP / UDP) to layer 7(FTP,HTTP)   

14. Please explain XML Service of Citrix?

Ans.

- An interface for HTTP is provided as a service to the ICA browser.

- TCP packets are used by this XML Service.

- TCP in XML Service allows to work across many firewalls.

- The port that supports Citrix XML Service is 80.   


15. Can you please explain what is shadowing?

Ans.

- The Shadowing feature enables one user to join remotely to another user.

- One user can access the session of another user remotely.
By joining remotely, the user accessing another user, can diagnose or take technical support from the other user.   


16. How to remove a dead server from the Citrix Management Console?

Ans.

- Execute the DSVERIFY SERVERS /CLEAN /FORCE for optimizing the Data Store.

- DSVerify can run on any of the server in the farm.

- MetaFrame feature release 3 has a command line tool known as DSCHECK.

- Use the following command using DSVerify command line tool:
--- DSCHECK / CHECK

- Or right click on the ‘server in the farm’ and click ‘Remove Server from Farm’.

- Use this option when the servers no longer operational.


17. Tell me what is the use of Independent Management Architecture?

Ans.

- IMA has a data store, a database to store MetaFrame XP configuration information.

- IMA has a protocol, to transfer the changing data between MetaFrame XP servers including server load and current user connections.

- IMA verifies the connections between Citrix Presentation Server and Citrix Management Console.

- Its architecture is separated from Windows Management Architecture.

- IMA is linked with Meta Frame Common Object Model (MF-COM) services.

- These links enables to remove individual servers from Citrix Management Console.


18. Please tell us what are the services provided by Citrix?

Ans.

The services that are provided by Citrix are:

- Citrix Virtual Memory Optimization Service.

- Encryption Service.

- Citrix XTE Service.

- Independent Management Architecture.

- Citrix SMA Service (Switch Monitoring and Accessories).

- Secure Gateway Service.

- Diagnostic Facility Common Object Model (COM) Service.   


19. Tell us what is the purpose of Zones?
Ans.

- Data collector persist information about user’s session, Zones and published applications.

- A farm has subset known as Zone.

- Zone has various server members.

- One of the server members is Zone Data Collector.

- Communications is established among Zones using ZDCs.

- Zones are useful in traffic controlling.   

20. Do you know what is Citrix?

Ans.

- Citrix is an application deployment system.

- Applications are delivered to remote systems.

- Using Citrix, one can access the customized applications.

- Citrix allows users to share documents among users.

- Emails can be accessed using citrix.

- Citrix allows file transfer from home computer to office computer.   

21. Can you explain what is Local Host Cache (LHC) and what is the purpose of LHC?

Ans.

- The LHC is a name given to the MS Access database which is created on every local MPS server.

- It stores the partitions of the Data Store to keep the server function, when an outrage occurs.

- When the data store goes offline, the server will continue functioning normally

- The LHC database enables the data store functionality up to 48 hours.

- LHC will ensure the data accessibility that is pertinent locally, even though the database is not available.   

22. Can you please explain what are the ports associated with Citrix services?

Ans.

- Default ICA port is A: 1494.

- Default listening port for Citrix XML Service is 80.

- ICA : 1494.

- UDP port used for client broadcasting is 1604.

- IMA port numbers are 2512, 2513.

- CMC, SSL port number is 443.

- Server to SQL port is 1433.

- Port for Session Reliability is 2598.

- Port number for licensing is 27000.   

23. Do you know how does Citrix work?

Ans.

- To work with Citrix, install the Terminal Services of OS.

- Citrix allows multiple users to execute multiple applications on its server.

- At the time of running the applications, the screen shots are sent to the client system.

- The keyboard inputs and mouse movements are sent to the Citrix Server.

- Then the accessibility to the applications is done by client.

- Citrix will back up the applications’ data, if required by the client.   


24. Please tell us what is the need of Data Store?

Ans.

- Data Store is a database which contains all the configuration information required by the Citrix Farm.

- Changes can be made at any time to the Meta Frame Server.

- These changes are persisted in the Data Store.

- Data store will store the following information:

1. Server Configuration.
2. User Configuration.
3. Print Environment.
4. Published Application   

25. Can you please explain what are the effective uses of Citrix?

Ans.

- Users can gain access to remote systems by configuring dial up settings.

- Users can backup data on the remote drive from their workstations.

- Microsoft Outlook accessibility is faster for dialup users

- Cloud computing is made effective using Citrix

- Allows maintaining virtualization to manage virtual data centers and maintain virtual work styles.

26. What are the steps to clearing xenserver cache?

Ans.

Dnscmd ServerName /clearcache   

Read More

Datastage Interview Questions and Answers

Datastage interview questions and answers for freshers and experienced professionals. These IBM Datastage FAQ's are prepared by subject experts.
 
1) Define Data Stage?

Ans.

A data stage is basically a tool that is used to design, develop and execute various applications to fill multiple tables in data warehouse or data marts. It is a program for Windows servers that extracts data from databases and change them into data warehouses. It has become an essential part of IBM WebSphere Data Integration suite.

2) Explain how a source file is populated?

Ans.

We can populate a source file in many ways such as by creating a SQL query in Oracle, or  by using row generator extract tool etc.

3) Name the command line functions to import and export the DS jobs?

Ans.

To import the DS jobs, dsimport.exe is used and to export the DS jobs, dsexport.exe is used.




4) What is the difference between Datastage 7.5 and 7.0?

Ans.

In Datastage 7.5 many new stages are added for more robustness and smooth performance, such as Procedure Stage, Command Stage, Generate Report etc.




5) In Datastage, how you can fix the truncated data error?

Ans.

The truncated data error can be fixed by using ENVIRONMENT VARIABLE ‘ IMPORT_REJECT_STRING_FIELD_OVERRUN’.




6) Define Merge?

Ans.

Merge means to join two or more tables.
The two tables are joined on the basis of Primary key columns in both the tables.




7) Differentiate between data file and descriptor file?

Ans.

As the name implies, data files contains the data and the descriptor file contains the description/information about the data in the data files.




8) Differentiate between datastage and informatica?

Ans.

In datastage, there is a concept of partition, parallelism for node configuration.
While, there is no concept of partition and parallelism in informatica for node configuration.
Also, Informatica is more scalable than Datastage.
Datastage is more user-friendly as compared to Informatica.




9) Define Routines and their types?

Ans.

Routines are basically collection of functions that is defined by DS manager.
It can be called via transformer stage.
There are three types of routines such as, parallel routines, main frame routines and server routines.




10) How can you write parallel routines in datastage PX?

Ans.

We can write parallel routines in C or C++ compiler.
Such routines are also created in DS manager and can be called from transformer stage.




11) What is the method of removing duplicates, without the remove duplicate stage?

Ans.

Duplicates can be removed by using Sort stage. We can use the option, as allow duplicate = false.




12) What steps should be taken to improve Datastage jobs?

Ans.

In order to improve performance of Datastage jobs, we have to first establish the baselines.
Secondly, we should not use only one flow for performance testing.
Thirdly, we should work in increment. Then, we should evaluate data skews.
Then we should isolate and solve the problems, one by one. After that, we should distribute the file systems to remove bottlenecks, if any. Also, we should not include RDBMS in start of testing phase. Last but not the least, we should understand and assess the available tuning knobs.




13) Differentiate between Join, Merge and Lookup stage?

Ans.

All the three concepts are different from each other in the way they use the memory storage, compare input requirements and how they treat various records.
Join and Merge needs less memory as compared to the Lookup stage.




14) Explain Quality stage?

Ans.

Quality stage is also known as Integrity stage. It assists in integrating different types of data from various sources.




15) Define Job control?

Ans.

Job control can be best performed by using Job Control Language (JCL).
This tool is used to execute multiple jobs simultaneously, without using any kind of loop.




16) Differentiate between Symmetric Multiprocessing and Massive Parallel Processing?

Ans.

In Symmetric Multiprocessing, the hardware resources are shared by processor.
The processor has one operating system and it communicates through shared memory.
While in Massive Parallel processing, the processor access the hardware resources exclusively.
This type of processing is also known as Shared Nothing, since nothing is shared in this.
It is faster than the Symmetric Multiprocessing.




17) What are the steps required to kill the job in Datastage?
Ans.

To kill the job in Datasatge, we have to kill the respective processing ID.




18) Differentiate between validated and Compiled in the Datastage?

Ans.

In Datastage, validating a job means, executing a job.
While validating, the Datastage engine verifies whether all the required properties are provided or not.
In other case, while compiling a job, the Datastage engine verifies that whether all the given properties are valid or not.




19) How to manage date conversion in Datastage?

Ans.

We can use date conversion function for this purpose i.e. Oconv(Iconv(Filedname,”Existing Date Format”),”Another Date Format”).




20) Why do we use exception activity in Datastage?

Ans.

All the stages after the exception activity in Datastage are executed in case of any unknown error occurs while executing the job sequencer.




21) Define APT_CONFIG in Datastage?

Ans.

It is the environment variable that is used to identify the *.apt file in Datastage.
It is also used to store the node information, disk storage information and scratch information.




22) Name the different types of Lookups in Datastage?

Ans.

There are two types of Lookups in Datastage i.e. Normal lkp and Sparse lkp.
In Normal lkp, the data is saved in the memory first and then the lookup is performed.
In Sparse lkp, the data is directly saved in the database.
Therefore, the Sparse lkp is faster than the Normal lkp.





23) How a server job can be converted to a parallel job?

Ans.

We can convert a server job in to a parallel job by using IPC stage and Link Collector.




24) Define Repository tables in Datastage?

Ans.

In Datastage, the Repository is another name for a data warehouse. It can be centralized as well as distributed.




25) Define OConv () and IConv () functions in Datastage?

Ans.

In Datastage, OConv () and IConv() functions are used to convert formats from one format to another i.e. conversions of roman numbers, time, date, radix, numeral ASCII etc. IConv () is basically used to convert formats for system to understand.
While, OConv () is used to convert formats for users to understand.




26) Explain Usage Analysis in Datastage?

Ans.

In Datastage, Usage Analysis is performed within few clicks. Launch Datastage Manager and right click the job.
Then, select Usage Analysis and that’s it.




27) How do you find the number of rows in a sequential file?

Ans.

To find rows in sequential file, we can use the System variable @INROWNUM.




28) Differentiate between Hash file and Sequential file?

Ans.

The only difference between the Hash file and Sequential file is that the Hash file saves data on hash algorithm and on a hash key value, while sequential file doesn’t have any key value to save the data.
Basis on this hash key feature, searching in Hash file is faster than in sequential file.




29) How to clean the Datastage repository?

Ans.

We can clean the Datastage repository by using the Clean Up Resources functionality in the Datastage Manager.




30) How a routine is called in Datastage job?

Ans.

In Datastage, routines are of two types i.e. Before Sub Routines and After Sub Routines.
We can call a routine from the transformer stage in Datastage.




31) Differentiate between Operational Datastage (ODS) and Data warehouse?

Ans.

We can say, ODS is a mini data warehouse.
An ODS doesn’t contain information for more than 1 year while a data warehouse contains detailed information regarding the entire business.




32) NLS stands for what in Datastage?

Ans.

NLS means National Language Support.
It can be used to incorporate other languages such as French, German, and Spanish etc.
In the data, required for processing by data warehouse.
These languages have same scripts as English language.




33) Can you explain how could anyone drop the index before loading the data in target in Datastage?

Ans.

In Datastage, we can drop the index before loading the data in target by using the Direct Load functionality of SQL Loaded Utility.




34) How can one implement the slowly changing dimensions in Datastage?

Ans.

Slowly changing dimensions is not a concept related to Datastage.
Datastage is used for ETL purpose and not for slowly changing dimensions.




35) How can one find bugs in job sequence?

Ans.

We can find bugs in job sequence by using DataStage Director.




36) How complex jobs are implemented in Datstage to improve performance?

Ans.

In order to improve performance in Datastage, it is recommended, not to use more than 20 stages in every job.
If you need to use more than 20 stages then it is better to use another job for those stages.




37) Name the third party tools that can be used in Datastage?

Ans.

The third party tools that can be used in Datastage, are Autosys, TNG and Event Co-ordinator.
I have worked with these tools and possess hands on experience of working with these third party tools.




38) Define Project in Datastage?

Ans.

Whenever we launch the Datastage client, we are asked to connect to a Datastage project.
A Datastage project contains Datastage jobs, built-in components and Datastage Designer or User-Defined components.




39) How many types of hash files are there?

Ans.

There are two types of hash files in DataStage i.e. Static Hash File and Dynamic Hash File.
The static hash file is used when limited amount of data is to be loaded in the target database.
The dynamic hash file is used when we don’t know the amount of data from the source file.




40) Define Meta Stage?

Ans.

In Datastage, MetaStage is used to save metadata that is helpful for data lineage and data analysis.



41) Have you have ever worked in UNIX environment and why it is useful in Datastage?

Ans.

Yes, I have worked in UNIX environment.
This knowledge is useful in Datastage because sometimes one has to write UNIX programs such as batch programs to invoke batch processing etc.




42) Differentiate between Datastage and Datastage TX?

Ans.

Datastage is a tool from ETL (Extract, Transform and Load) and Datastage TX is a tool from EAI (Enterprise Application Integration).




43) What is size of a transaction and an array means in a Datastage?

Ans.

Transaction size means the number of row written before committing the records in a table.
An array size means the number of rows written/read to or from the table respectively.




44) How many types of views are there in a Datastage Director?

Ans.

There are three types of views in a Datastage Director i.e. Job View, Log View and Status View.




45) Why we use surrogate key?

Ans.

In Datastage, we use Surrogate Key instead of unique key. Surrogate key is mostly used for retrieving data faster.
It uses Index to perform the retrieval operation.




46) How rejected rows are managed in Datastage?

Ans.

In the Datastage, the rejected rows are managed through constraints in transformer.
We can either place the rejected rows in the properties of a transformer or we can create a temporary storage for rejected rows with the help of REJECTED command.




47) Differentiate between ODBC and DRS stage?

Ans.

DRS stage is faster than the ODBC stage because it uses native databases for connectivity.




48) Define Orabulk and BCP stages?

Ans.

Orabulk stage is used to load large amount of data in one target table of Oracle database.
The BCP stage is used to load large amount of data in one target table of Microsoft SQL Server.




49) Define DS Designer?

Ans.

The DS Designer is used to design work area and add various links to it.




50) Why do we use Link Partitioner and Link Collector in Datastage?

Ans.

In Datastage, Link Partitioner is used to divide data into different parts through certain partitioning methods.
Link Collector is used to gather data from various partitions/segments to a single data and save it in the target table.

Read More

Data Structures Interview Questions and Answers

Data Structures Interview Questions and Answers For Freshers and Experienced. Data Structures FAQ's.

1) What is data structure?
 
Data structure refers to the way data is organized and manipulated. It seeks to find ways to make data access more efficient. When dealing with data structure, we not only focus on one piece of data, but rather different set of data and how they can relate to one another in an organized manner.



2) Differentiate file structure from storage structure.

Basically, the key difference is the memory area that is being accessed. When dealing with the structure that resides the main memory of the computer system, this is referred to as storage structure. When dealing with an auxiliary structure, we refer to it as file structure.



3) When is a binary search best applied?

A binary search is an algorithm that is best applied to search a list when the elements are already in order or sorted. The list is search starting in the middle, such that if that middle value is not the target search key, it will check to see if it will continue the search on the lower half of the list or the higher half. The split and search will then continue in the same manner.



4) What is a linked list?

A linked list is a sequence of nodes in which each node is connected to the node following it. This forms a chain-like link of data storage.



5) How do you reference all the elements in a one-dimension array?

To do this, an indexed loop is used, such that the counter runs from 0 to the array size minus one. In this manner, we are able to reference all the elements in sequence by using the loop counter as the array subscript.


6) In what areas do data structures applied?

Data structure is important in almost every aspect where data is involved. In general, algorithms that involve efficient data structure is applied in the following areas: numerical analysis, operating system, A.I., compiler design, database management, graphics, and statistical analysis, to name a few.



7) What is LIFO?

LIFO is short for Last In First Out, and refers to how data is accessed, stored and retrieved. Using this scheme, data that was stored last , should be the one to be extracted first. This also means that in order to gain access to the first data, all the other data that was stored before this first data must first be retrieved and extracted.



8 ) What is a queue?

A queue is a data structure that can simulates a list or stream of data. In this structure, new elements are inserted at one end and existing elements are removed from the other end.



9) What are binary trees?

A binary tree is one type of data structure that has two nodes, a left node and a right node. In programming, binary trees are actually an extension of the linked list structures.



10) Which data structure is applied when dealing with a recursive function?

Recursion, which is basically a function that calls itself based on a terminating condition, makes use of the stack. Using LIFO, a call to a recursive function saves the return address so that it knows how to return to the calling function after the call terminates.



11) What is a stack?

A stack is a data structure in which only the top element can be accessed. As data is stored in the stack, each data is pushed downward, leaving the most recently added data on top.



12) Explain Binary Search Tree

A binary search tree stores data in such a way that they can be retrieved very efficiently. The left subtree contains nodes whose keys are less than the node’s key value, while the right subtree contains nodes whose keys are greater than or equal to the node’s key value. Moreover, both subtrees are also binary search trees.



13) What are multidimensional arrays?

Multidimensional arrays make use of multiple indexes to store data. It is useful when storing data that cannot be represented using a single dimensional indexing, such as data representation in a board game, tables with data stored in more than one column.



14) Are linked lists considered linear or non-linear data structure?

It actually depends on where you intend to apply linked lists. If you based it on storage, a linked list is considered non-linear. On the other hand, if you based it on access strategies, then a linked list is considered linear.



15) How does dynamic memory allocation help in managing data?

Aside from being able to store simple structured data types, dynamic memory allocation can combine separately allocated structured blocks to form composite structures that expand and contract as needed.



16) What is FIFO?

FIFO is short for First-in, First-out, and is used to represent how data is accessed in a queue. Data has been inserted into the queue list the longest is the one that is removed first.



17) What is an ordered list?

An ordered list is a list in which each node’s position in the list is determined by the value of its key component, so that the key values form an increasing sequence, as the list is traversed.



18) What is merge sort?

Merge sort takes a divide-and-conquer approach to sorting data. In a sequence of data, adjacent ones are merged and sorted to create bigger sorted lists. These sorted lists are then merged again to form an even bigger sorted list, which continuous until you have one single sorted list.



19) Differentiate NULL and VOID.

Null is actually a value, whereas Void is a data type identifier. A variable that is given a Null value simply indicates an empty value. Void is used to identify pointers as having no initial size.



20) What is the primary advantage of a linked list?

A linked list is a very ideal data structure because it can be modified easily. This means that modifying a linked list works regardless of how many elements are in the list.



21) What is the difference between a PUSH and a POP?

Pushing and popping applies to the way data is stored and retrieved in a stack. A push denotes data being added to it, meaning data is being “pushed” into the stack. On the other hand, a pop denotes data retrieval, and in particular refers to the topmost data being accessed.



22) What is a linear search?

A linear search refers to the way a target key is being searched in a sequential data structure. Using this method, each element in the list is checked and compared against the target key, and is repeated until found or if the end of the list has been reached.



23) How does variable declaration affect memory allocation?

The amount of memory to be allocated or reserved would depend on the data type of the variable being declared. For example, if a variable is declared to be of integer type, then 32 bits of memory storage will be reserved for that variable.




24) What is the advantage of the heap over a stack?

Basically, the heap is more flexible than the stack. That’s because memory space for the heap can be dynamically allocated and de-allocated as needed. However, memory of the heap can at times be slower when compared to that stack.




25) What is a postfix expression?

A postfix expression is an expression in which each operator follows its operands. The advantage of this form is that there is no need to group sub-expressions in parentheses or to consider operator precedence.



26) What is Data abstraction?

Data abstraction is a powerful tool for breaking down complex data problems into manageable chunks. This is applied by initially specifying the data objects involved and the operations to be performed on these data objects without being overly concerned with how the data objects will be represented and stored in memory.



27) How do you insert a new item in a binary search tree?

Assuming that the data to be inserted is a unique value (that is, not an existing entry in the tree), check first if the tree is empty. If it’s empty, just insert the new item in the root node. If it’s not empty, refer to the new item’s key. If it’s smaller than the root’s key, insert it into the root’s left subtree, otherwise, insert it into the root’s right subtree.



28) How does a selection sort work for an array?

The selection sort is a fairly intuitive sorting algorithm,, though not necessarily efficient. To perform this, the smallest element is first located and switched with the element at subscript zero, thereby placing the smallest element in the first position. The smallest element remaining in the subarray is then located next with subscripts 1 through n-1 and switched with the element at subscript 1, thereby placing the second smallest element in the second position. The steps are repeated in the same manner till the last element.




29) How do signed and unsigned numbers affect memory?

In the case of signed numbers, the first bit is used to indicate whether positive or negative, which leaves you with one bit short. With unsigned numbers, you have all bits available for that number. The effect is best seen in the number range (unsigned 8 bit number has a range 0-255, while 8-bit signed number has a range -128 to +127.




30) What is the minimum number of nodes that a binary tree can have?

A binary tree can have a minimum of zero nodes, which occurs when the nodes have NULL values. Furthermore, a binary tree can also have 1 or 2 nodes.




31) What are dynamic data structures?

Dynamic data structures are structures that expand and contract as a program runs. It provides a flexible means of manipulating data because it can adjust according to the size of the data.



32) In what data structures are pointers applied?

Pointers that are used in linked list have various applications in data structure. Data structures that make use of this concept include the Stack, Queue, Linked List and Binary Tree.



33) Do all declaration statements result in a fixed reservation in memory?

Most declarations do, with the exemption of pointers. Pointer declaration does not allocate memory for data, but for the address of the pointer variable. Actual memory allocation for the data comes during run-time.



34) What are ARRAYs?

When dealing with arrays, data is stored and retrieved using an index that actually refers to the element number in the data sequence. This means that data can be accessed in any order. In programming, an array is declared as a variable having a number of indexed elements.



35) What is the minimum number of queues needed when implementing a priority queue?

The minimum number of queues needed in this case is two. One queue is intended for sorting priorities while the other queue is intended for actual storage of data.




36) Which sorting algorithm is considered the fastest?

There are many types of sorting algorithms: quick sort, bubble sort, balloon sort, radix sort, merge sort, etc. Not one can be considered the fastest because each algorithm is designed for a particular data structure and data set. It would depend on the data set that you would want to sort.



37) Differentiate STACK from ARRAY.

Data that is stored in a stack follows a LIFO pattern. This means that data access follows a sequence wherein the last data to be stored will the first one to be extracted. Arrays, on the other hand, does not follow a particular order and instead can be accessed by referring to the indexed element within the array.



38) Give a basic algorithm for searching a binary search tree.

1. if the tree is empty, then the target is not in the tree, end search
2. if the tree is not empty, the target is in the tree
3. check if the target is in the root item
4. if target is not in the root item, check if target is smaller than the root’s value
5. if target is smaller than the root’s value, search the left subtree
6. else, search the right subtree



39) What is a dequeue?

A dequeue is a double-ended queue. This is a structure wherein elements can be inserted or removed from either end.



40) What is a bubble sort and how do you perform it?

A bubble sort is one sorting technique that can be applied to data structures such as an array. It works by comparing adjacent elements and exchanges their values if they are out of order. This method lets the smaller values “bubble” to the top of the list, while the larger value sinks to the bottom.



41) What are the parts of a linked list?

A linked list typically has two parts: the head and the tail. Between the head and tail lie the actual nodes, with each node being linked in a sequential manner.



42) How does selection sort work?

Selection sort works by picking the smallest number from the list and placing it at the front. This process is repeated for the second position towards the end of the list. It is the simplest sort algorithm.



43) What is a graph?

A graph is one type of data structure that contains a set of ordered pairs. These ordered pairs are also referred to as edges or arcs, and are used to connect nodes where data can be stored and retrieved.



44) Differentiate linear from non linear data structure.

Linear data structure is a structure wherein data elements are adjacent to each other. Examples of linear data structure include arrays, linked lists, stacks and queues. On the other hand, non-linear data structure is a structure wherein each data element can connect to more than two adjacent data elements. Examples of non linear data structure include trees and graphs.



45) What is an AVL tree?

An AVL tree is a type of binary search tree that is always in a state of partially balanced. The balance is measured as a difference between the heights of the subtrees from the root. This self-balancing tree was known to be the first data structure to be designed as such.




46) What are doubly linked lists?

Doubly linked lists are a special type of linked list wherein traversal across the data elements can be done in both directions. This is made possible by having two links in every node, one that links to the next node and other one that links to the previous node.



47) What is Huffman’s algorithm?

Huffman’s algorithm is associated in creating extended binary trees that has minimum weighted path lengths from the given weights. It makes use of a table that contains frequency of occurrence for each data element.



48) What is Fibonacci search?

Fibonacci search is a search algorithm that applies to a sorted array. It makes use of a divide-and-conquer approach that can greatly reduce the time needed in order to reach the target element.



49) Briefly explain recursive algorithm.

Recursive algorithm targets a problem by dividing it into smaller, manageable sub-problems. The output of one recursion after processing one sub-problem becomes the input to the next recursive process.




50) How do you search for a target key in a linked list?

To find the target key in a linked list, you have to apply sequential search. Each node is traversed and compared with the target key, and if it is different, then it follows the link to the next node. This traversal continues until either the target key is found or if the last node is reached.

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