Dynamic Host Configuration Protocol (DHCP)

Dynamic Host Configuration Protocol (DHCP) is a protocol used by networked devices (clients) to obtain the parameters necessary for operation in an Internet Protocol network. This protocol reduces system administration workload, allowing devices to be added to the network with little or no manual configurations.

Applicability: Dynamic Host Configuration Protocol is a way to manage network parameter assignment from a single DHCP server, or a group of DHCP servers arranged in a fault-tolerant manner. Even in small networks, Dynamic Host Configuration Protocol is useful because it can make it easy to add new machines to the local network.
DHCP is also recommended even in the case of servers whose addresses rarely change, so that if a server needs to be readdressed changes can be made in as few places as possible.

DHCP can be used to directly assign addresses to servers and desktop machines and through a Point-to-Point Protocol (PPP) proxy, to dialup and broadband on-demand hosts, as well as for residential Network address translation (NAT) gateways and routers.

NAT: In computer networking, network address translation is a technique of transceiving network traffic through a router that involves re-writing the source and/or destination IP addresses and usually also the TCP/UDP port numbers of IP packets as they pass through. Checksums (both IP and TCP/UDP) must also be rewritten to take account of the changes.

Common Object Request Broker Architecture (CORBA)

The Common Object Request Broker Architecture (CORBA) is a standard defined by the Object Management Group (OMG) that enables software components written in multiple computer languages and running on multiple computers to work together.It is a mechanism in software for normalizing the method-call semantics between application objects that reside either in the same address space (application) or remote address space (same host, or remote host on a network).

CORBA uses an interface definition language (IDL) to specify the interfaces that objects will present to the outside world. CORBA then specifies a “mapping” from IDL to a specific implementation language like C++ or Java.

IDL:
An interface description language or interface definition language or IDL, is a specification language used to describe a software component's interface. IDLs describe an interface enabling communication between software components that do not share a language - for example, between components written in C++ and components written in Java.

IP Address and Classes

The Internet Protocol moves data between hosts in the form of datagrams. Each datagram is delivered to the address contained in the Destination Address (word 5) of the datagram's header. The Destination Address is a standard 32-bit IP address that contains sufficient information to uniquely identify a network and a specific host on that network.
An IP address contains a network part and a host part, but the format of these parts is not the same in every IP address. The number of address bits used to identify the network, and the number used to identify the host, vary according to the prefix length of the address. There are two ways the prefix length is determined: by address class or by a CIDR address mask.
Address Classes
Originally, the IP address space was divided into a few fixed-length structures called address classes. The three main address classes are class A, class B, and class C.
1. If the first bit of an IP address is 0, it is the address of a class A network. The first bit of a class A address identifies the address class. The next 7 bits identify the network, and the last 24 bits identify the host. There are fewer than 128 class A network numbers, but each class A network can be composed of millions of hosts.
2.If the first 2 bits of the address are 1 0, it is a class B network address. The first 2 bits identify class; the next 14 bits identify the network, and the last 16 bits identify the host. There are thousands of class B network numbers and each class B network can contain thousands of hosts.
3.If the first 3 bits of the address are 1 1 0, it is a class C network address. In a class C address, the first 3 bits are class identifiers; the next 21 bits are the network address, and the last 8 bits identify the host. There are millions of class C network numbers, but each class C network is composed of fewer than 254 hosts.
4. If the first 4 bits of the address are 1 1 1 0, it is a multicast address. These addresses are sometimes called class D addresses, but they don't really refer to specific networks. Multicast addresses are used to address groups of computers all at one time. Multicast addresses identify a group of computers that share a common application, such as a video conference, as opposed to a group of computers that share a common network.
5. If the first four bits of the address are 1 1 1 1, it is a special reserved address. These addresses are sometimes called class E addresses, but they don't really refer to specific networks. No numbers are currently assigned in this range.

My understanding about com object.

com object acts as an interface between one application and another. Eg. our VB application is connected to the database through ADODB com object. This com object acts as an interface between our VB application and the database.

Virtual Sticky Notes

Hi got this information from The hindu news paper.
Now, virtual sticky notes
New York: Software that enables mobile phone users to obtain location-specific, real-time information, either actively or passively, from other users across the world has been developed by a team led by an Indian-American Professor at Duke University.
The rapid convergence of social networks, mobile phones and global positioning technology has given Duke University engineers the ability to create “virtual sticky notes” — site-specific messages that people can leave for others to pick up on their mobile phones.
Romit Roy Choudhury, Assistant Professor at Duke’s Pratt School of Engineering, said: “Every mobile phone can act as a telescope lens providing real-time information about its environment to any of the three billion mobile phones worldwide.” It will be as if every participating mobile phone works together allowing each individual access to information throughout the virtual network.

Microsoft Foundation Classes

The Microsoft Foundation Class Library, also Microsoft Foundation Classes or MFC is a library that wraps portions of the Windows API in C++ classes, including functionality that enables them to use a default application framework. Classes are defined for many of the handle-managed Windows objects and also for predefined windows and common controls.

what is registry and problems associated with it?

What Is a Windows System Registry?
The system registry is one of the most important parts of a Windows-based computer system. Not to be tampered with lightly, the registry is a system-defined database used by the Windows operating systems to store configuration information. Most Windows applications write data to the registry during installation, and system components store and retrieve configuration data through the registry. The data stored in the registry varies according to the version of Microsoft Windows.

Problems Associated With The Registry:

• Users can experience computer problems caused by system registry errors for several reasons. Problems with the computer itself will usually occur because of invalid or missing keys in the Windows registry.
• Some signs of trouble include computer system crashes, stalls, or even a noticeably slower operating speed. In most cases, problems with your registry occur from user actions mainly involving the installation or removal of software and hardware on your computer.
• If you frequently install or uninstall programs, delete startup programs, change hardware and do not remove old drivers (or have corrupted hardware drivers), delete software which was not properly uninstalled, or have installed a program with embedded spyware on your computer, then you may experience problems with your Windows system registry

Basic Network Types

Peer-to-peer Networks:
Nearly all Operating Systems come with the ability to act as some kind of a server to share resources. You can setup different computers to allow others to use its peripherals such as printers or CDROM drives, and other computers to allow others to read or write to its hard disk allowing sharing of files, while other computers may allow access to its Internet connection. When you allow workstation computers to become servers and share things in this manner, it is called a Peer-to-peer network
The Benefits of a Peer-to-peer Network:
Peer-to-peer networks are very cheap to implement because more than likely the Operating System software you have installed on your computers should have the ability to share items with other computers on the network, even though the feature may be limited.

Client-Server Networks:
The Client-Server network model usually consists of one or more server computers that provide services and information to a number of workstation computers. These services can consist of many different roles, including: file services, web services, email services, domain name lookup services, document version system services, Internet sharing services, etc. A great example of the Client-Server network model is actually the World Wide Internet. On the Internet clients, or computer with web browsers, access web sites that are hosted on servers.
The Benefits of a Client-Server Network:
1) Security is relatively easy to implement with this type of network model, since you can setup a single server computer to handle all information requests or login requests for the entire network, thus you only need one username and password for each user on the network. So if you ever need to change a password, you only need to change it at the server and the password would be changed for the entire network.
2) Information control is also fundamentally easier with this type of network model because you can have individual server computers store all the important documents of you company on a single store. In doing this you gain the ability to easily archive all the companies documents, as well as provide a secure, easy to access network store for all of your users, reducing the possibility of misplaced documents on your network.

Application-Server Network:
The final network type is the Application Server based Networks, sometimes called Terminal Server based. The idea behind this type of network is that you basically have one high-end server or mainframe, and all the network clients are "dumb terminals", meaning that none of the processing is actually done on the terminals, instead the only job the terminals have is to provide input and show the display on the monitor.
Benefits of Application-Server Networks:
The biggest benefit that this type of network provides is cost. It is very cheap to implement and maintain an Application Server based network.
The maintenance of this type of network is also very low cost, since you basically only need to maintain the one or two servers that provide the applications. Also, to lower the cost even more, you can install and use commodity software, such as Linux or BSD Unix, which can be obtained with little or no cost.

Types Of Clients

Clients are generally classified as:

Fat Client:
A fat client (also known as a thick client or rich client) is a client that performs the bulk of any data processing operations itself, and does not necessarily rely on the server. The fat client is most common in the form of a personal computer, as the personal computers or laptops can operate independently. Programming environments for rich clients include Curl, Delphi,Droplets,.Net, Java, win32 and X11.

Thin Client:
A thin client is a minimal sort of client. Thin clients use the resources of the host computer. A thin client's job is generally just to graphically display pictures provided by an application server, which performs the bulk of any required data processing. Programming environments for thin clients include JavaScript/AJAX (client side automation), ASP, JSP, Ruby on Rails, Python's Django, PHP and other (depends on server-side backend and uses HTML pages or rich media like Flash, Flex or Silverlight on client).

Hybrid client:
A hybrid client is a mixture of the above two client models. Similar to a fat client, it processes locally, but relies on the server for storage data. This approach offers features from both the fat client (multimedia support, high performance) and the thin client (high manageability, flexibility).

DIFFERENCE BETWEEN DLL AND REGISTRY

Dll stand for Dynamic Link Library. These files are used by applications to perform their specified tasks. In broad sense we can say that, these are the common files used by many applications in order to minimize ammount of disk space they consume on your hard drive and to improve memory performance.
Whereas,registry is an executable file which contains all the information about your Windows OS. This is not shared by number of applications. Every application have their own registry entries.Any change in the registry will corrupt the os.

Windows registry

The Windows registry is a directory which stores settings and options for the operating system for Microsoft Windows 32-bit versions, 64-bit versions, and Windows Mobile. It contains information and settings for all the hardware, operating system software, most non-operating system software, users, preferences of the PC, etc. Whenever a user makes changes to Control Panel settings, file associations, system policies, or most installed software, the changes are reflected and stored in the registry. The registry also provides a window into the operation of the kernel, exposing runtime information such as performance counters and currently active hardware.

COM,DCOM,DLL

COM:

Component Object Model Microsofts standard for distributed objects, an object encapsulation technology that specifies interfaces between component objects within a single application or between applications. It separates the interface from the implementation and provides APIs for dynamically locating objects and for loading and invoking them .

DCOM:

Distributed Component Object Model?Microsoft?s protocol that enables software components to communicate directly over a network in a reliable, secure, and efficient manner. DCOM is based on the DCE-RPC specification and works with both Java applets and ActiveX components through its use of the COM.

DLL:
A DLL (Dynamic Link Library) is a file that can be loaded and executed by programs dynamically. Basically it's an external code repository for programs. Since usually several different programs reuse the same DLL instead of having that code in their own file, this dramatically reduces required storage space. A synonym for a DLL would be library.The Dynamic Linked Library (DLL) is a compiled and linked collection of computer functi ons that are not immediately bound to an executable, but are called during program execution. Dynamic linking means that the data in a library is not copied into a new executable or library at compile time, but remains in a separate file on disk.

A New FireFox

Let me start my contribution to enlighten ourselves with the latest advancements in technologies with this useful article which was published in The Hindu newspaper on 19th June 2008.
Mozilla-the popular web browser has released an improved version of its Firefox(i.e)the FireFox3 on Tuesday(17th June 2008).This new version is fast(twice as fast as its predecessor),secure and is available in 50 languages. Over 15000 improvements have been done to it when compared to its predecessor which includes revolutionary smart location bar, malware protection etc.
Free downloads of this version can done from http://www.getfirefox.com
Firefox 3 is available free for computers using Windows,Linux & Macintosh operating systems.

Welcome Note

Dear Students
I extend a warm welcome to you all to join this blog not just in my capacity as your lecturer for the subject but more enthusiatically as your peer learner. So let's start sharing what we know and what we find under this vast topic "Technology Today". I hope we make our blog the most sought after and well know for it's rich and useful information content.
Let's start it girls!