SDE - 1

This can be done by iterative swapping using two pointers. The first pointer points to the beginning of the string, whereas the second pointer points to the end. Both pointers keep swapping their elements and go towards each other. Essentially, the algorithm simulates the rotation of a string with respect to its midpoint.
Time Complexity : O(n)

Deadlock is a situation where a set of processes are blocked because each process is holding a resource and waiting for another resource acquired by some other process.
Deadlock can arise if the following four conditions hold simultaneously (Necessary Conditions) 
Mutual Exclusion: One or more than one resource are non-shareable (Only one process can use at a time) 
Hold and Wait: A process is holding at least one resource and waiting for resources. 
No Preemption: A resource cannot be taken from a process unless the process releases the resource. 
Circular Wait: A set of processes are waiting for each other in circular form.

A thread is a path of execution within a process. A process can contain multiple threads.
There are two types of threads.
User Level Thread
Kernel Level Thread

1. The availability of more than one processor per system, that can execute several set of instructions in parallel is known as multiprocessing. The concurrent application of more than one program in the main memory is known as multiprogramming.
2. The number of CPU is more than one in multiprocessing. The number of CPU is one in multiprogramming.
3. Multiprocessing takes less time for job processing. Multiprogramming takes more time to process the jobs.
4.In multiprocessing, more than one process can be executed at a time. In multiprogramming, one process can be executed at a time.
5. Multiprocessing is economical. Multiprogramming is economical.
6.he number of users can be one or more than one in multiprocessing. The number of users is one at a time in multiprogramming.

Process life cycle in OS is one of the five states in which a process can be starting from the time it has been submitted for execution, till the time when it has been executed by the system. A process can be in any of the following states –
New state
Ready state
Running state
Waiting state
Terminated

1. Worldwide release : 
Windows 7 : October 22, 2009
Windows XP : October 25, 2001
2. Stable release : 
Windows 7 : February 22, 2011
Windows XP : April 21, 2008
3. Kernel type : 
Windows 7 : Hybrid
Windows XP : Hybrid
4. Platform support :
Windows 7 : IA-32 and x86-64
Windows XP : IA-32, x86-64 and Itanium
5. Preceded by : 
Windows 7 : Windows Vista
Windows XP : Windows 2000 , Windows ME
6. Succeeded by :
Windows 7 : Windows 8
Windows XP : Windows Vista
7. Physical Memory Limits :
Windows 7 : 2 – 192 GB depending on the version and architecture.
Windows XP : 4 GB-128 GB depending on the version and the architecture.

1. DBMS stores data as file. RDBMS stores data in tabular form.
2. Data elements need to access individually in DBMS. Multiple data elements can be accessed at the same time in RDBMS.
3. No relationship between data in DBMS. Data is stored in the form of tables which are related to each other in RDBMS.
4. In DBMS, Normalization is not present. In RDBMS, Normalization is present.
5. DBMS does not support distributed database. RDBMS supports distributed database.

An object-oriented database (OOD) is a database system that can work with complex data objects — that is, objects that mirror those used in object-oriented programming languages.
In object-oriented programming, everything is an object, and many objects are quite complex, having different properties and methods. An object-oriented database management system works in concert with an object-oriented programming language to facilitate the storage and retrieval of object-oriented data.

To count the number of different values that are stored in a given column, you simply need to designate the column you pass in to the COUNT function as DISTINCT. When given a column, COUNT returns the number of values in that column. Combining this with DISTINCT returns only the number of unique (and non-NULL) values.

A Hub is a networking device that allows you to connect multiple PCs to a single network, whereas a Switch connects various devices together on a single computer network.
A Hub operates on the physical layer, whereas Switch operates on the data link layer.
Hub uses Half-duplex cable on the other hand Switch uses Full duplex cables
Hub is a passive device while the switch is an active device
Hub uses electrical signal orbits while switch uses frame & packet

Physical Layer
The lowest layer of the OSI Model is concerned with electrically or optically transmitting raw unstructured data bits across the network from the physical layer of the sending device to the physical layer of the receiving device. It can include specifications such as voltages, pin layout, cabling, and radio frequencies.

Data Link Layer
At the data link layer, directly connected nodes are used to perform node-to-node data transfer where data is packaged into frames. The data link layer also corrects errors that may have occurred at the physical layer.
The data link layer encompasses two sub-layers of its own. The first, media access control (MAC), provides flow control and multiplexing for device transmissions over a network. The second, the logical link control (LLC), provides flow and error control over the physical medium as well as identifies line protocols.

Network Layer
The network layer is responsible for receiving frames from the data link layer, and delivering them to their intended destinations among based on the addresses contained inside the frame. The network layer finds the destination by using logical addresses, such as IP (internet protocol). At this layer, routers are a crucial component used to quite literally route information where it needs to go between networks.

Transport Layer
The transport layer manages the delivery and error checking of data packets. It regulates the size, sequencing, and ultimately the transfer of data between systems and hosts. One of the most common examples of the transport layer is TCP or the Transmission Control Protocol.

Session Layer
The session layer controls the conversations between different computers. A session or connection between machines is set up, managed, and terminated at layer 5. Session layer services also include authentication and reconnections.

Presentation Layer
The presentation layer formats or translates data for the application layer based on the syntax or semantics that the application accepts. Because of this, it at times also called the syntax layer. This layer can also handle the encryption and decryption required by the application layer.

Application Layer
At this layer, both the end user and the application layer interact directly with the software application. This layer sees network services provided to end-user applications such as a web browser or Office 365. The application layer identifies communication partners, resource availability, and synchronizes communication.

Layer 7 Application SMTP, HTTP, FTP, POP3, SNMP
Layer 6 Presentation MPEG, ASCH, SSL, TLS
Layer 5 Session NetBIOS, SAP
Layer 4 Transport TCP, UDP
Layer 3 Network IPV5, IPV6, ICMP, IPSEC, ARP, MPLS.
Layer 2 Data Link RAPA, PPP, Frame Relay, ATM, Fiber Cable, etc.
Layer 1 Physical RS232, 100BaseTX, ISDN, 11.

Tip 1 : Be sure to do your homework on the organization and its culture before the interview.
Tip 2 : Employers want to understand how you use your time and energy to stay productive and efficient. Be sure to emphasize that you adhere to deadlines and take them seriously.
Tip 3 : Talk about a relevant incident that made you keen on the profession you are pursuing and follow up by discussing your education.