Virtualization

Virtualization:
Allow multiple Operating System instances to run concurrently on a single computer. it is a mean of seperating hardware from single Operating System.
Each guest OS is managed by virtual machine monitor (VMM). Also known as Hypervisor, because the virtulization sits between guest and hardware. It can control guest's CPU,memory storage and even allowing a guest OS to migrate from one machine to another. It is the creation of Virtual (rather than actual) version of something such as OS,Server,Storage device or N/W resources.

Why Virtualization:

• Increase manageability,security and flexibility in (H/S) IT environment
• Provide maximum system utilization by consolidating multiple environment in single server/PC
• By abstracting s/w away from underlying h/w- new usage model opens up that reduce cost, increase management, efficiency, strengthen security, while making your computing infrastructure more resilient in event of disaster.
• Reduce power and cooling requirement.

Advantage of Virtualization

• Server Consolidation
• Reduce power and cooling requirement
• Green computing
• Ease of Deployment and administration
• High availability and disaster recovery

Test case for any Object & Electric Item

Hey Friends,

We are facing so many interviews with questions like, try to write test case for pen, paper, bottle, mobile, washing machine, coffee machine, fan etc. But when they ask, we only explain whatever at that time in our mind. Here I give some tips for the answer of this question, For almost any object we can give some cases common like

1. Look and Feel: Colour, height, design, width, Material etc
2. Performance: durability, continuous perform or not
3. Usability: Easy to use, accessibility etc
4. Rigidity: How strong, how work in abnormal condition etc.
5. Configuration: how configure the machine,
6. Functionality: how it function with each switch n function
7. Security: how secure that machine or item

For example, if Pen is given, then for pen you can say:

what is the color of pen? which color ink with it? what is the material of pen either rubber, plastic ? which brand's pen? is all the spell and information on pen is proper or not? how easy to use that pen? when you write can you able to write it continuous or not ? If you through it, then it will break or not? if you hit it then also its able to write or not? how long you are able to write ? etc etc.

Hope this will help you to write or give answer of such kind of questions. If you find anything new, then please update it in comments so we can get all information at one place.

Difference between Automation Testing & Manual Testing

Hey folks,

I tried to write difference between automation and manual testing. If anyone fine any new, then wrote comments so all can get it from once place.

Automation Testing:

• Repetitive work is reduced (e.g., running regression tests, re-entering the same test data, and checking against coding standards)
• Greater consistency and repeatability (e.g., tests executed by a tool in the same order with the same frequency, and tests derived from requirements)
• Tools should have compatibility with our development or deployment
• If requirement change continuously then not suitable
• Automated tools are not OS compatible, require huge space on hard disk, ex. quality centre.
• Underestimating the time, cost and effort for the initial introduction of a tool (including training and external expertise)
• Fast,Reliable,Program reuse,Flexible
• Objective assessment (e.g., static measures, coverage)
• Ease of access to information about tests or testing (e.g., statistics and graphs about testprogress, incident rates and performance)
• Underestimating the time and effort needed to achieve significant and continuing benefits from the tool (including the need for changes in the testing process and continuous improvement of the way the tool is used)
• Underestimating the effort required to maintain the test assets generated by the tool
• Poor response from vendor for support, upgrades, and defect fixes
• Unforeseen, such as the inability to support a new platform
• Risk of suspension of open-source / free tool project

Manual Testing:

• Need lots of time
• We cannot do some kind of testing manually like performance and load testing
• It is suitable if requirement change continuously.
• Not easy to manage and track of work

Difference between TCP and UDP

Difference between TCP and UDP

There are two types of internet protocol (IP) traffic, and both have very different uses.

1. TCP(Transmission Control Protocol). TCP is a connection-oriented protocol, a connection can be made from client to server, and from then on any data can be sent along that connection.

•  Reliable - when you send a message along a TCP socket, you know it will get there unless the connection fails completely. If it gets lost along the way, the server will re-request the lost part. This means complete integrity, things don't get corrupted.
• Ordered - if you send two messages along a connection, one after the other, you know the first message will get there first. You don't have to worry about data arriving in the wrong order.
• Heavyweight - when the low level parts of the TCP "stream" arrive in the wrong order, resend requests have to be sent, and all the out of sequence parts have to be put back together, so requires a bit of work to piece together.
• Streaming: Data is read as a "stream," with nothing distinguishing where one packet ends and another begins. There may be multiple packets per read call.
• Examples: World Wide Web (Apache TCP port 80), e-mail (SMTP TCP port 25 Postfix MTA), File Transfer Protocol (FTP port 21) and Secure Shell (OpenSSH port 22) etc.

2.  UDP(User Datagram Protocol). A simpler message-based connectionless protocol. With UDP you send messages (packets) across the network in chunks.

• Unreliable - When you send a message, you don't know if it'll get there, it could get lost on the way.
• Not ordered - If you send two messages out, you don't know what order they'll arrive in.
• Lightweight - No ordering of messages, no tracking connections, etc. It's just fire and forget! This means it's a lot quicker, and the network card / OS have to do very little work to translate the data back from the packets.
• Datagrams: Packets are sent individually and are guaranteed to be whole if they arrive. One packet per one read call.
• Examples: Domain Name System (DNS UDP port 53), streaming media applications such as IPTV or movies, Voice over IP (VoIP), Trivial File Transfer Protocol (TFTP) and online multiplayer games etc

Reference: http://www.cyberciti.biz/faq/key-differences-between-tcp-and-udp-protocols/