Windows Troubleshooting

Hello i am writing this post about troubleshooting guide of windows so let you will learn about troubleshooting of windows.

This videos tutorial about windows troubleshooting instructed by Mr Mark Russinovich. Mark is master of Windows troubleshooting. Mark will show you step by step how he solved several system and windows application problems on windows. Mark also shows that how you can use MDT(Microsoft Debugging Tools) and also own system internals tools including Process Explorer and Process Monitor to solve system crashes process hangs security vulnerabilities DLL conflicts permissions problems registry misconfiguration network hangs and file system issues and also many more issues. Microsoft use these tools on daily basis Product Support and it have been used solve several types of desktop and several issues.

Wmv | Wmv3 | 960x560 | 560kbps | 48kbps 44100hz | 400 MB

Part 1
Part 2
Part 3
Part 4

If link will dead comment here i will upload again here.

Java Script & Ajax for Dummies

Hello friends i am sharing this post about leaning of Java Script and Ajax and learn how to use these powerful tools together and build Web sites that work.

If anyone want to build web pages that offer some valued to your visitors AJAX and java script are top tools for the job. Even if any one new to web programming, this book helps you create sites any designer will admire. With easy to understand steps and an emphasis on free tools you'll be able to jump right into building a site using the same techniques as the pros
In this book you will get.

� How to choose a test browser
� How to discuss string concatenation with a straight face
� Tips for debugging your code
� How to add useful information to a dropdown list
� Why AJAX connections should be asynchronous
� The exciting possibilities of the jQuery library
� How to use the Aptana editor
� Online resources for javascript programmers

Click here.

Now you can access any Wireless network

Hello friends i am writing this post about Wireless network that how you can use any wireless network
As we know wireless networks are everywhere they are widely available cheap and very easy to setup. As my own experience to avoid the hassle of setting up a wired network i chose to get wireless. After getting my wireless network i was enjoying wireless freedom then i began thinking about security of wireless .
How secure is my wireless network for this purpose i research on internet for many days reading articles gathering information and participating on message boards and forums. I soon came to the realization that the best way for me to understand the security of my wireless network would be to test it myself. Some peoples said it was easy few said it was hard.
How a wireless network works!
A wireless local area network (WLAN) is the linking of 2 or more computers with Network Interface Cards (NICs) through a technology based on radio waves. All devices that can connect to a wireless network are known as stations. Stations can be access points (APs), or clients.
Access points are base stations for the wireless network. They receive and transmit information for the clients to communicate with.
The set of all stations that communicate with each other is referred to as the Basic Service Set (BSS). Every BSS has an Identification known as a BSSID, also known as the MAC address, which is a unique identifier that is associated with every NIC.
For any client to join a WLAN, it should know the SSID of the WLAN; therefore, the access points typically broadcast their SSID to let the clients know that an AP is in range.
Data streams, known as packets, are sent between the Access Point, and it�s clients. You need no physical access to the network or its wires to pick up these packets, just the right tools. It is with the transmission of these packets that pose the largest security threat to any wireless network.
Wireless Encryption
The majority of home and small business networks are encrypted using the two most popular methods:

1.  WEP
2.  WPA

WEP. Wired Equivalent Privacy  comes in 3 different key lengths: 64, 128, and 256 bits, known as WEP 64, WEP 128, and WEP 256 respectively. WEP provides a casual level of security but is more compatible with older devices; therefore, it is still used quite extensively. Each WEP key contains a 24 bit Initialization Vector (IV), and a user-defined or automatically generated key; for instance, WEP 128 is a combination of the 24 bit IV and a user entered 26 digit hex key. ((26*4)+24=128)
WEP also comes in WEP2 and WEP+, which are not as common and still as vulnerable as the standard WEP encryption.
WPA � WiFi Protected Access � comes in WPA and WPA2, and was created to resolve several issues found in WEP. Both provide you with good security; however, they are not compatible with older devices and therefore not used as widely. WPA was designed to distribute different keys to each client; however, it is still widely used in a (not as secure) pre-shared key (PSK) mode, in which every client has the same passphrase.
To fully utilize WPA, a user would need an 802.1x authentication server, which small businesses and typical home users simply cannot afford. WPA utilizes a 48 bit Initialization Vector (IV), twice the size of WEP, which combined with other WEP fixes, allows substantially greater security over WEP.
Packets and IVs
It�s all in the packets. The bottom line is � while you may be able to employ several security features on your WLAN � anything you broadcast over the air can be intercepted, and could be used to compromise the security on your network. If that frightens you, start stringing wires throughout your home.
Every encrypted packet contains a 24 or 48 bit IV, depending on the type of encryption used. Since the pre-shared key is static and could be easily obtained, the purpose of the IV is to encrypt each packet with a different key. For example, to avoid a duplicate encryption key in every packet sent, the IV is constantly changing. The IV must be known to the client that received the encrypted packet in order to decrypt it; therefore, it is sent in plaintext.
The problem with this method is that the Initialization Vectors are not always the same. In theory, if every IV was different, it would be nearly impossible to obtain the network key; this is not the case. WEP comes with a 24 bit IV; therefore, giving the encryption 16 million unique values that can be used. This may sound like a large number, but when it comes to busy network traffic, it�s not.
Every IV is not different; and this is where the issues arise. Network hackers know that all the keys used to encrypt packets are related by a known IV (since the user entered WEP part of the key is rarely changed); therefore, the only change in the key is 24 bits. Since the IV is randomly chosen, there is a 50% probability that the same IV will repeat after just 5,000 packets; this is known as a collision.
If a hacker knows the content of one packet, he can use the collision to view the contents of the other packet. If enough packets are collected with IV matches, your network�s security can be compromised.
The Setup
My wireless network was powered by a Linksys WRT54G v6 wireless router; It is well known that this model is the most widely used wireless router. Out of the box, the Linksys router came with 1 CD which was nothing more than a visual step by step, what you should do to connect it.
A few things concern me with this router. There was no part in the setup that allowed me, or even told me to change my router�s default password. To change the password, I had to go into the router�s web-based setup utility; this was accessible via the IP address 192.168.1.1 in my Internet browser. The default username and password was admin. If someone was able to compromise the security on my network, they could have easily done this for me; and locked me out of my own network. Sure, I could have performed a hard reset on the router, but I�d have little luck without the Internet or any documentation to help.
If you�re looking to find your default username and password, there is quite a comprehensive list located at www.phenoelit.de My advice is to change this immediately, for it may save you some trouble down the road.
Being my first time, I decided to go easy; I set my router up with a basic WEP 64 encryption; it required a 10 digit hex key. I entered the key into the 2 other computers in my home, and I was ready to start.
Hardware
Out of everything I�ve experienced over the last couple weeks, this was the hardest obstacle, by far. I started with a Dell Latitude C610 notebook with a Linksys WPC54GS Wireless-G notebook adapter (Broadcom chipset) running Windows XP Pro; looking back, it was a bad choice.
When selecting hardware, be warned, not all network cards are the equal. It turns out that nearly 99% of the software used to crack network keys are not compatible with notebook cards that have a Broadcom chipset; the ones that were just didn�t work.
9 out of every 10 articles I read boasted the Orinoco Gold PCMCIA network card by Lucent was the absolute best pick and most compatible will all the good software. A trip to E-Bay, $30 later, and I was ready.
The software we will be using is strictly dependent on the chipset of the WNIC, and unfortunately, the operating system. Your best approach would be to research what software you will be using, and then find a card based on the chipset the software is compatible with.
There are many types of chipsets; too many, in fact, to mention. Linux-wlan.org has an unbelievably comprehensive list of WNICs and their corresponding chipset.
All the best programs are made for Linux; windows is certainly a drag when it comes to WLAN penetrating software, but if you don�t have Linux, don�t be too concerned.
It may be in your best interest to invest in a wireless card that has an external antenna jack. The Orinoco Gold WNIC I purchased has one, but since I�m compromising my own network in a short range, it won�t be necessary.
The Software
There are hundreds of applications you can use to do a variety of things with wireless networks. The largest list of software, that I came across, can be found at Wardrive.net. The term �wardriving� is more commonly used for this practice, and involves driving around neighborhoods to look for wireless networks. I refuse to use this term because that is not what I am doing; I am sitting in my home testing the vulnerabilities of my own network.
Let it be known, that it is not illegal to use software to detect the presence of wireless networks; however, if you crack the network and start �stealing� bandwidth, you could be in a world of trouble. Especially if you�re in Singapore.
Once I received my Orinoco card, I began re-installing software which did not previously work with my Linksys card. It was a nightmare; Windows XP kept getting in the way, software that had been moded to run on windows required daunting tasks for installation, some programs simply didn�t work, some required special run time modules to be installed.
After nearly 48 hours of time-wasting, aggravating, disappointment; I came across the answer. A small penguin shone a beam of light upon my browser and blessed me; I found Auditor.
(2/6/07 - The link is currently not working, but you can obtain Auditor through any Torrent service.)
Auditor Security Collection is a self booting Linux-based CD that comes pre-loaded with all the best security software for auditing a system. It comes in a .ISO file that can be downloaded from remote-exploit.org; the ISO image file is roughly 649 Mb, and can be burned to a CD or DVD using most CD/DVD writing utilities.
It was truly amazing; a simple check in the Bios of the laptop to set the boot order to CD/DVD first, a slip of the Auditor CD, and a press of the power button was all it took. I was ready. Be not afraid of this Linux-based CD; everything is laid out on a GUI and all commands have �shortcuts� linking to them on a desktop similar to a windows environment.
Auditor Security Collection does not touch a single file on your hard drive. All files used and saved in the ASC are stored in your notebook�s RAM; once you remove the CD and reboot, everything is exactly as it was.
Detecting my wireless network
If you�ve come this far, believe me, you�re doing well. The first step is to find the network you want to penetrate. As there are a variety of apps that allow you to do this, we will be focusing in on the 2 most popular: Netstumbler, and Kismet.
Netstumber - is a widely popular tool used for detecting 802.11a/b/g wireless networks. The latest version is Netstumbler 0.4.0, and will run in Windows XP. For compatible hardware and requirements, you can check the read me on the Netstumbler forums; or you could just try it. I�d like to point out that many sources have said the Linksys WPC54G/S WNIC does not work with Netstumbler; however, I have been able to make it work by launching the program, then removing and re-inserting the WNIC. The Orinoco Gold works fine with Netstumbler.
Kismet � does a little more than just detecting networks. Aside from providing every detail about a network except the encryption key, Kismet is a packet sniffer and intrusion detection system; we�ll get into sniffing packets a little later.
For this demonstration, we�ll be using the pre-loaded Kismet on the Auditor Security Collection. After inserting and booting the Auditor CD, I was ready to make sure everything was working properly.
From this point, the first thing that needed to be done was to ensure the wireless card was recognized by Auditor; to do this, you will have to venture into the dark world of the command prompt. In Auditor, the command prompt can be reached by clicking on the little black monitor icon located at the bottom of your screen.
Simply typing in iwconfig will allow you to see all the wireless extensions configured on the machine. If you see a screen full of data next to a WLAN0 or ETH0, you�re ready to continue to the next step; otherwise, you will see a list of �no wireless extensions� messages.
Next, you will need to start the Kismet program. You�ll initially be prompted to enter a destination to save data to; you can just select the �desktop� and continue. When Kismet loads, you will see a black screen with green text showing all the wireless networks within you signal range.
Kismet will give you all the information you need to start cracking. Pressing �s� on your keyboard will bring up a �Sort Network� dialogue box. From there you can press any of the desired sorting methods. This step is important as it allows you to select a particular wireless network on a list to view more details. Select your network with the arrow keys and press enter.
You will then be looking at nearly all your network details such as name, ssid, server IP, bssid, etc� Most are not relevant in this case, but you should write down a few things:

1. BSSID
2. Channel #
3. Encryption method

Pressing �x� in Kismet will return you to the previous screen. re-select your target WLAN; then press �SHFT+C� to bring up a list of associated clients to the Access Point. Write down the MAC address of all clients as it will prove useful.
Capturing packets
While you may have not been aware, at this point, Kismet has also been capturing packets. This is the bread and butter of cracking any wireless encryption; without data to process you have nothing.
Capturing packets, also known as packet sniffing, is the process of intercepting and logging traffic passing over a network. As information is sent and received over your wireless network, the software captures every packet to allow you to analyze and decode it.
Capturing network traffic can be a timely process; especially if it is a slow network. With no-one on any computers in my home, I generally capture around 3,000 packets within 5 minutes; with users on the other 2 computers, this number is substantially greater. Don�t get confused, it�s not the packet itself that we want; but rather the IVs in the packets.
The programs we will be using to sniff packets are Kismet and Airodump (part of the Aircrack Suite). We�ve already touched Kismet, so lets take a look at Airodump.
Before running Airodump, you must configure your wireless interface to go into �monitor� mode; the methods to achieve this require you to go back to the command prompt (konsole).
For most WNICs, you would use the command:
iwconfig mode monitor
And in some instances would have to set the channel number on your WNIC to match that of the target access point:
iwconfig channel #
Note that you will have to replace with the network interface specific to your machine. Using an Orinoco Gold card, my network interface was eth0; but on most machines, it is wlan0 or ath0. So you may have to adjust those commands accordingly. You can find out for sure by simply typing iwconfig.
I should also point out that putting the Orinoco Gold card in �monitor� mode had a different command altogether:
iwpriv eth0 monitor 2 1
Once your in monitor mode, you�re ready to run Airodump. The command used to start Airodump is:
airodump

[mac filter]

can be anything you wish; Airodump will put a .cap extension on the end of the name. The mac filter is used to only capture packets from a specific access point. For instance, I used:
airodump eth0 george 00:18:f8:65:fe:41
to capture packets just from my access point - where 00:18:f8:65:fe:41 is the BSSID of the AP.
Airodump looks similar to Kismet, but there are no selectable objects on the screen; it gets right down to it, capturing packets and storing them in the .cap file as defined in the command. You�ll notice Airodump keeps a running count of all the packets captured, and better yet, shows you the number of IVs collected.
The waiting game
The hard truth is that you will need to collect nearly 150,000 IVs to crack a 64 bit WEP key, and around 600,000 IVs to crack a 128 bit WEP key. This number varies, but is mostly dependent on how luck you are. If you watch the IV count in Airodump, you�ll notice that, under normal circumstances, they do not rise rapidly.
This can cause a problem; particularly if you�re as impatient as I am. Let�s take a look at some ways we can speed up this process.
Until now, we�ve been using a method known as a passive attack. A passive attack is basically doing nothing other than passively capturing packets until you have achieved enough data to perform the crack.
Most access points need their client to re-associate after a certain period of time to confirm their connection; therefore, the AP will send out an Address Resolution Protocol (ARP) packet. The ARP packet is unique in that is always addressed to the MAC address FF:FF:FF:FF:FF:FF, usually has a size of 68 bytes, and has the ToDS flag set.
We can use this information to implement an ARP replay attack. For this method, we will be using Aireplay (part of the Aircrack Suite). Aireplay can be used to actually re-send packets that it has received.
Leave Airodump running, and open a new command window. The command we�ll be using for Aireplay is:
aireplay -i -m 68 -n 68 -d ff:ff:ff:ff:ff:ff -b 00:18:f8:65:fe:41 eth0
The -i tells Aireplay to capture packets on the fly; the -m 68 and -n 68 tells aireplay that you only want it to replay packets that are 68 bytes. The -d and -b are the destination MAC address and AP MAC Address(BSSID) respectively. This is the criteria that is defined for our ARP packet, which is usually associated with an IV.
Alternatively, you may have already captured one of these packets. You can have Aireplay check the .cap file from Airodump with the -f switch:
aireplay -f george.cap -m 68 -n 68 -d ff:ff:ff:ff:ff:ff -b 00:18:f8:65:fe:41 eth0
In either case, If Aireplay finds a match to our specifications, it will show you the details of the packet and ask if you would like to replay it. If the details look exactly as shown below, press �y� for yes.
FromDS = 0, ToDS = 1
BSSID =
Src. MAC =
Dst. MAC = ff:ff:ff:ff:ff:ff
Aireplay will then begin to replay the packet; if you�ve found a winning packet, you will notice your packet and IV count in Airodump rise extremely quick. If not, only the packet count in Airodump will rise; If this be the case, press CTRL+C to abort the operation, restart aireplay, and try again.
It has been noted that some routers will detect this erratic behavior and block the MAC address of the WNIC you are using. Adding a -x switch followed by a �replay per second #� will slow down the rate at which Airplay replays these packets.
If your lucky enough, you will have collected enough IVs in little time. For me, it took 28 minutes including booting up, writing down the network specs, and typing all those lengthy commands.
There are other methods such as Dueth attacks which force the clients off the AP, causing them to have to re-associate; but these methods require a second computer.
The crack
Two of the most popular programs used for actually cracking the WEP key are Airsnort and Aircrack. Airsnort can be used with the .dump files that Kismet provides; and Aircrack can be used with the .cap files that Airodump provides.
Airsnort can be used on it�s own without any other software capturing packets; although, it has been reported to be extremely unstable in this state, and you should probably not chance loosing all your captured data. A better method would be to let Airsnort recover the encryption key from your Kismet .dump file. Kismet and Airsnort can run simultaneously.
For this demonstration, we�ll be using Aircrack. You can use Airodump to capture the packets, and Aircrack to crack the encryption key at the same time.
With Airodump running, open a new command window and type:
aircrack -f 3 -n 64 -q 3 george.cap
The -f switch followed by a number is the fudgefactor; which is a variable that the program uses to define how thoroughly it scans the .cap file. A larger number will give you a better chance of finding the key, but will usually take longer. The default is 2.
The -n switch followed by 64 represents that you are trying to crack a WEP 64 key. I knew because it was a setup; In the real world there is no way to determine what WEP key length a target access point is using. You may have to try both 64 and 128.
The -q 3 switch was used to display the progress of the software. It can be left out altogether to provide a faster crack; although, if you�ve obtained enough unique IVs, you should not be waiting more than a couple minutes.
A -m switch can be used, followed by a MAC address, to filter a specific AP�s usable packets; this would come in handy if you were collecting packets from multiple APs in Airodump.
Aircrack recovered my WEP 64 key within 1 minute using 76,000 unique IVs; the whole process took around 34 minutes.
The same experiment was repeated with WEP 128 and it took about 43 minutes. The reason it was not substantially longer is because I simply let Airplay replay more packets. Sometimes you can get lucky and capture an ARP Request packet within a few minutes; otherwise, it could take a couple hours.
After I had access to the network, many doors opened up. Aside from having access to the Internet, I was able to use Networkview � a network discovery tool � to obtain my network�s workgroup name. From there, I had access to all the shared files on my drives.
While I�m no expert in the subject, I can at least assume that many horrible things could happen if the wrong hands were to obtain my WLAN encryption key.
The conclusion
Always use WPA or WPA2 encryption when possible. If your using WPA with a pre-shared key, use a strong password; hackers can use dictionary attacks, and they will be quite effective if you have an easy password. You may want to use a strong password generator like the one at grc.com.
If your access point supports it, you may want to consider disabling wireless SSID broadcast; however, this may raise some issues with the APs clients recognizing it. (Kismet will still recognize it)
Many routers will allow you to filter what clients can access the network; this is known as Wireless MAC Filtering. If you know the MAC address of the clients you are using, you can enter them into your configuration utility as �Permit ONLY�. This is not a 100% effective method; MAC addresses can be cloned to match the AP�s associated clients, but it does provide you with a slightly higher level of security. (there is a utility on Auditor to allow you to do this)
By default, your router may be set to mixed mode; this allows 802.11b and 802.11g devices to access your network. If you use only 802.11g devices, set your router to G-ONLY. Had my router been set this way, I would have never been able to do any of this. The Orinoco Gold card is 802.11b, and is obviously not compatible with a 802.11g network. Many 802.11g cards are not supported by the software we�ve used in this tutorial, but few are. While your at it, please change your default router username and password.
While I haven�t tried my hand at cracking a WPA encryption, the methods are similar when the WLANs use pre-shared keys (psk); I do plan on trying it, and I will surely write an update to let you know how/if it was done.

Introduction to Internet

By the turn of the century, information, including access to the Internet, will be the basis for personal, economic, and political advancement. The popular name for the Internet is the information superhighway. Whether you want to find the latest financial news, browse through library catalogs, exchange information with colleagues, or join in a lively political debate, the Internet is the tool that will take you beyond telephones, faxes, and isolated computers to a burgeoning networked information frontier.
The Internet supplements the traditional tools you use to gather information, Data Graphics, News and correspond with other people. Used skillfully, the Internet shrinks the world and brings information, expertise, and knowledge on nearly every subject imaginable straight to your computer.


What is the Internet?

The Internet links are computer networks all over the world so that users can share resources and communicate with each other. Some computers, have direct access to all the facilities on the Internet such as the universities. And other computers, eg privately-owned ones, have indirect links through a commercial service provider, who offers some or all of the Internet facilities. In order to be connected to Internet, you must go through service suppliers. Many options are offered with monthly rates. Depending on the option chosen, access time may vary.
The Internet is what we call a metanetwork, that is, a network of networks that spans the globe. It's impossible to give an exact count of the number of networks or users that comprise the Internet, but it is easily in the thousands and millions respectively. The Internet employs a set of standardized protocols which allow for the sharing of resources among different kinds of computers that communicate with each other on the network. These standards, sometimes referred to as the Internet Protocol Suite, are the rules that developers adhere to when creating new functions for the Internet.
The Internet is also what we call a distributed system; there is no central archives. Technically, no one runs the Internet. Rather, the Internet is made up of thousands of smaller networks. The Internet thrives and develops as its many users find new ways to create, display and retrieve the information that constitutes the Internet. 

History & Development of the Internet:

In its infancy, the Internet was originally conceived by the Department of Defense as a way to protect government communications systems in the event of a military strike. The original network, dubbed ARPANet (for the Advanced Research Projects Agency that developed it) evolved into a communications channel among contractors, military personnel, and university researchers who were contributing to ARPA projects.
The network employed a set of standard protocols to create an effective way for these people to communicate and share data with each other.
ARPAnet's popularity continued to spread among researchers, and in the 1980's the National Science Foundation, whose NSFNet, linked several high speed computers, took charge of the what had come to be known as the Internet.
By the late 1980's, thousands of cooperating networks were participating in the Internet.
In 1991, the U.S. High Performance Computing Act established the NREN (National Research & Education Network). NREN's goal was to develop and maintain high-speed networks for research and education, and to investigate commercial uses for the Internet.
The rest, as they say, is history in the making. The Internet has been improved through the developments of such services as Gopher and the World Wide Web.
Even though the Internet is predominantly thought of as a research oriented network, it continues to grow as an informational, creative, and commercial resource every day and all over the world.



Who Pays for the Internet?

There is no clear answer to this question because the Internet is not one "thing", it's many things. No one central agency exists that charges individual Internet users. Rather, individuals and institutions who use the Internet pay a local or regional Internet service provider for their share of services. And in turn, those smaller Internet service providers might purchase services from an even larger network. So basically, everyone who uses the Internet in some way pays for part of it.



2-what makes the internet work?

The unique thing about the Internet is that it allows many different computers to connect and talk to each other. This is possible because of a set of standards, known as protocols, that govern the transmission of data over the network: TCP/IP (Transmission Control Protocol/Internet Protocol). Most people who use the Internet aren't so interested in details related to these protocols. They do, however, want to know what they can do on the Internet and how to do it effectively.



The Client/Server Model:

The most popular Internet tools operate as client/server systems. You're running a program called a Web client. This piece of software displays documents for you and carries out your requests. If it becomes necessary to connect to another type of service--say, to set up a Telnet session, or to download a file--your Web client will take care of this, too. Your Web client connects (or "talks") to a Web server to ask for information on your behalf.

The Web server is a computer running another type of Web software which provides data, or "serves up" an information resource to your Web client.

All of the basic Internet tools--including Telnet, FTP, Gopher, and the World Wide Web--are based upon the cooperation of a client and one or more servers. In each case, you interact with the client program and it manages the details of how data is presented to you or the way in which you can look for resources. In turn, the client interacts with one or more servers where the information resides. The server receives a request, processes it, and sends a result, without having to know the details of your computer system, because the client software on your computer system is handling those details.
The advantage of the client/server model lies in distributing the work so that each tool can focus or specialize on particular tasks: the server serves information to many users while the client software for each user handles the individual user's interface and other details of the requests and results.



The Use of Local Clients:

Every computer should be equipped with basic client software packages that allow you to perform functions such as electronic mail, Telnet, Gopher, and FTP.



Electronic mail on the internet:

Electronic mail, or e-mail, is probably the most popular and widely used Internet function. E-mail, email, or just mail, is a fast and efficient way to communicate with friends or colleagues. You can communicate with one person at a time or thousands; you can receive and send files and other information. You can even subscribe to electronic journals and newsletters. You can send an e-mail message to a person in the same building or on the other side of the world.



How does E-mail Work?

E-mail is an asynchronous form of communication, meaning that the person whom you want to read your message doesn't have to be available at the precise moment you send your message. This is a great convenience for both you and the recipient.

On the other hand, the telephone, which is a synchronous communication medium, requires that both you and your listener be on the line at the same time in order for you to communicate (unless you leave a voice message). It will be impossible to discuss all the details of the many e-mail packages available to Internet users.
Fortunately, however, most of these programs share basic functionality which allow you to:
*send and receive mail messages
*save your messages in a file
*print mail messages
*reply to mail messages
*attach a file to a mail message



Reading an Internet Address:
To use Internet e-mail successfully, you must understand how the names and addresses for computers and people on the Internet are formatted. Mastering this technique is just as important as knowing how to use telephone numbers or postal addresses correctly.
Fortunately, after you get the hang of them, Internet addresses are usually no more complex than phone numbers and postal addresses.
And, like those methods of identifying a person, an organization, or a geographic location--usually by a telephone number or a street address--Internet addresses have rules and conventions for use.
Sample Internet Address: custcare@aucegypt.edu
The Internet address has three parts:
1.a user name [custcare in the example above]
2.an "at" sign (@)
3.the address of the user's mail server [aucegypt.edu in the example above] Sometimes it's useful to read an Internet address (like custcare@aucegypt.edu) or a domain name from right to left because it helps you determine information about the source of the address.
An address like 201B6DQF@asu.edu doesn't tell me much about the person who's sending me a message, but I can deduce that the sender is affiliated with an educational institution because of the suffix edu.
The right-most segment of domain names usually adhere to the naming conventions listed below:



EDU Educational sites in the United States
COM Commercial sites in the United States
GOV Government sites in the United States
NET Network administrative organizations
MIL Military sites in the United States
ORG Organizations in the U.S. not covered by the categories above (e.g., non-profit orginaizations).
.xx where xx is the country code (e.g., .eg for Egypt).
Introduction:

Once you've become adept at using e-mail, you may want to communicate with others on the Internet who share your interests. Newsgroups are one way to do this; the other is through an electronic discussion group. An electronic discussion is a group of persons who have come together to discuss a particular topic via e-mail. There are several methods that network users can use to participate in electronic discussions; however, the basic purpose is to bring together persons with similar interests to share information, ideas, problems, solutions, and opinions. Since an electronic discussion is conducted by e-mail, it's commonly called a mailing list.
If you find yourself interested in a topic, you can subscribe to a suitable mailing list. From then on, any message sent to the mailing list is automatically distributed as electronic mail to you--as well as to all previously subscribed members of that particular discussion. The beauty of a mailing list is that traffic (the mail generated by that list) covers a specific topic and the
mail it generates comes straight to your electronic mailbox, without any extra work on your part. There are thousands of mailing lists operating on the Internet, dedicated to myriad topics. Some are created to serve local needs only (i.e., a list for the members of a regional computer user group), while many are open to anyone on the network. There are discussions on professional topics, vocational subjects, and topics of personal interest. You can roughly separate the thousands of mailing lists available on the Internet into the following groups:

Types of discussion lists:

Moderated vs. Unmoderated Lists
Mailing lists can be moderated or unmoderated. The distinction is whether messages are automatically forwarded to all subscribers (unmoderated) or whether a moderator (a human being) first screens and perhaps combines similar messages before sending them to subscribers (moderated).

Open vs. Closed Lists
Electronic discussions can also be "open" or "closed." Anyone can subscribe to an open discussion, but a closed discussion is limited to a particular group of persons, for example, those in a particular professional field.



Introduction to network news:

Network News (sometimes referred to as Usenet News) is a service comprised of several thousand electronic discussions providing users an effective way to share information with others on just about any topic.

If you're unclear about the concept of Network News, it's helpful to think about a bulletin
board that you might see on campus.
Here, one might find posted messages advertising a futon for sale, asking for students to join a math study group. In the newsgroup environment, the same kind of process take place:
User X may access a newsgroup on a particular topic and post a message, question, or respond to a previously posted message, and anyone accessing that newsgroup would then be able to see User X's message.
Network News newsgroups provide this same kind of forum online, where users have access to the messages posted by all other users of that newsgroup.
Network News has been described as an "international meeting place" where you're likely to find a discussion going on just about anything.



How Does Network News work?

Messages posted on Network News newsgroups are sent from host computer to host computer all over the world, using the network news transfer protocol.
Because Network News newsgroups are located on one server, Network News is a very efficient way to share information that might otherwise be disseminated to several individual users.
This way, several people can read a given newsgroup message, but the host system stores only one copy of it.



Newsgroups: What's in a Name?

As mentioned before, Network News is essentially made up of newsgroups, each newsgroup a collection of messages focusing on a related theme.
You can probably find a newsgroup on any topic, no matter how arcane or bizarre.
A newsgroup's name gives you a good idea of that group's focus, and also illustrates the hierarchical naming scheme given to newsgroups.
Newsgroups with the prefix comp, for example, are for computer-related topics.
After the initial prefix, you'll see an additional series of names assigned to the newsgroup that tell its specific concern: Note the following examples:

comp.mac.performa for "computers--macintosh--performas"
rec.auto.antique for "recreation--autos--antiques"
alt.backrubs for "alternative--backrubs"
soc.culture.japan for "social--culture--japan"



Remote Login & File Transfer:
Introduction to telnet:
Telnet is the protocol used to establish a login session on a remote computer on the network. While many computers on the Internet require users to have authorization, others are open to the public and can be logged onto with telnet. Telnet is not a method to transfer files from one machine to another, but rather is a way to remotely connect to another system with priveleges to run specific programs on that system. Some uses of the Telnet protocol include:
connecting to a library catalog to search that library's collection connecting to a location that allows public priveleges to search its campus information system connecting to a location that gives you an up-to-the minute weather report

Basic Telnet Commands
open - establishes a connection to the specified host.close - closes an open connection and leaves you in the telnet software quit - closes any open telnet sessions and exits the telnet software. When using a telnet program like NCSA Telnet, you invoke these commands by way of pull-down menus or command keys.

Introduction to FTP, File Transfer Protocol:
Basic commands in FTP:
To do FTP, a user invokes one of two commands:
get the command for transferring a file from another server to your own computer.
put the command for moving a file from your computer to another one.
Who can do FTP? Anonymous vs. authorized priveleges
On many servers, called anonymous FTP servers, anyone can do FTP. All that is required to login is a username (anonymous) and a password (your e-mail address). To get an idea of the many resources available via FTP, you can look at this selected list of FTP servers.
Other servers require you to be a registered "authorized" user before you're permitted to do FTP. In such a case, you would need to contact the system operator for the server you wish to access, and request an authorization and a password. Getting an authorization and password might mean that you can get and put only to specific subdirectories on that server.

Resources available to you via FTP

Freeware
When you download freeware, the author continues to carry the copyright to the software, but permits you to use the program for free. You can share freeware with others, as long as you don't sell it.

Public Domain
When you download public domain software, you can use it freely. The creator carries no copyright, and has released it for anyone to use. There are no limits on distribution or sale--and anyone can modify the program.

Shareware
When you download shareware, the author continues to carry the copyright to the software, but you're permitted short-term use of the program for evaluation purposes.
At the end of evaluation period, you must either pay the copyright holder for the program or destroy all copies you've made of it.

Introduction to Gopher:

Gopher is a client/server system that allows you to access many Internet resources simply by making selections from a sequence of menus. Each time you make a selection, Gopher carries out your request to the computer that contains the information and "serves" it up. For example, if you select a menu item that represents a text file, Gopher will get that file--wherever it happens to be--and display it for you. As you use Gopher, some menu items lead to other menus. If you choose one of these, Gopher will retrieve the new menu and display it for you. Thus you can move from menu to menu, using only a few key strokes or a mouse to navigate. The power of Gopher is that the resources listed in a menu may be anywhere on the Internet. As Gopher connects to computers to comply with your menu selection, you don't need to be preoccupied with the behind-the-scenes work of connecting to and disconnecting from these various computers. Gopher does this for you without your even needing to be aware of it. This automatic connecting makes Gopher popular and useful.

Where did Gopher come from?

"Born" in April 1991, gopher began as a project at the Microcomputer, Workstation, and Networks Center at the University of Minnesota to help people on campus get answers to computer-related questions. At the time, the computer center staff had accumulated answers to thousands of questions regarding computers and software.
What was needed was an easy and efficient way to deliver this information to students, faculty and staff. Thus, the creation of Gopher reaffirms the adage that necessity is the mother of invention.

Why is it called Gopher?

The name "Gopher" is appropriate for three reasons:
1.Just as a real gopher successfully navigates beneath the prairie, the Internet Gopher tunnels through the invisible paths of the Internet to help you find the information you want.
2.The name refers to someone who fetches things or provides service for other people.
3.The Golden Gopher is the mascot of the University of Minnesota.

Introduction to the World Wide Web

The World Wide Web (also referred to as WWW or W3) is the fastest growing area of the Internet. While gopher was an important step in allowing users to "browse" through the Internet's vast resources, the World Wide Web has raised excitement about the Internet to new heights.
What makes the World Wide Web appealing and innovative is its use of hypertext as a way of linking documents to each other. A highlighted word or phrase in one document acts as a pointer to another document that amplifies or relates to the first document. When looking at a WWW document, the reader doesn't have to follow every pointer, or link (also called a hypertext link), only those that look interesting or useful. In this way, the user tailors the experience to suit his or her needs or interests. The other very appealing aspect of the World Wide Web is the use of graphics and sound capabilities. Documents on the WWW include text, but they may also include still images, video, and audio for a very exciting presentation. People who create WWW documents often include a photograph of themselves along with detailed professional information and personal interests. (This is often called a person's home page.)

What makes the WWW work?

WWW is another example of client/server computing. Each time a link is followed, the client is requesting a document (or graphic or sound file) from a server (also called a Web server) that's part of the World Wide Web that "serves" up the document. The server uses a protocol called HTTP or HyperText Transport Protocol. The standard for creating hypertext documents for the WWW is HyperText Markup Language or HTML. HTML essentially codes plain text documents so they can be viewed on the Web.



Uniform Resource Locators, or URLs:

A Uniform Resource Locator, or URL is the address of a document you'll find on the WWW. Your WWW browser interprets the information in the URL in order to connect to the proper Internet server and to retrieve your desired document. Each time you click on a hyperlink in a WWW document, you're actually instructing your browser to find the URL that's embedded within the hyperlink.
The elements in a URL:Protocol://server's address/filename
Hypertext protocol: http://www.aucegypt.edu
Gopher protocol: gopher://gopher.umm.tc.edu
File Transfer Protocol: ftp://ftp.dartmouth.edu
Telnet Protocol: telnet://pac.carl.org
News Protocol: news:alt.rock-n-roll.stones

WWW Clients, or "Broswers":

The program you use to access the WWW is known as a browser because it "browses" the WWW and requests these hypertext documents. Browsers can be graphical, like Netscape and Mosaic, allowing you to see and hear the graphics and audio; text-only browsers (i.e., those with no sound or graphics capability) are also available. All of these programs understand
http and other Internet protocols such as FTP, gopher, mail, and news, making the WWW a kind of "one stop shopping" for Internet users.

Chatting:

Internet Relay Chat (IRC), the other method for Internet conversation, is less common than talk because someone must set up the Chat before others can join in. Chat sessions allow many users to join in the same free-form conversation, usually centered around a discussion topic. When users see a topic that interests them, they type a command to join and then type another command to choose a nickname. Nicknames allow people in the session to find you on IRC Networks or Channels.

A look at search engines:

The World Wide Web is "indexed" through the use of search engines, which are also referred to as "spiders," "robots," "crawlers," or "worms". These search engines comb through the Web documents, identifying text that is the basis for keyword searching. Each search engine works in a different way. Some engines scan for information in the title or header of the document; others look at the bold "headings" on the page for their information. The fact that search engines gather information differently means that each will probably yield different results. Therefore, it's wise to try more than one search engine when doing Web searching.

The list below lists several search engines and how each one gathers information, plus resources that evaluate the search engines.

Selected Search Engines (listed alphabetically)
Alta Vista
Alta Vista, maintained by The Digital Equipment Corp., indexes the full text of over 16 million pages including newsgroups. Check out the Alta Vista Tips page.

Excite Netsearch
Excite includes approximately 1.5 million indexed pages, including newsgroups. Check out the Excite NetSearch handbook.

InfoSeek Net Search
Indexes full text of web pages, including selected newsgroups and electronic journals.
Just under one-half million pages indexed. Check out the InfoSeek Search Tips.

Inktomi
As of December 1995, the Inktomi search engine offers a database of approximately 2.8 million indexed Web documents and promises very fast search retrievals. Results are ranked in order of how many of your searched terms are used on the retrieved pages.

Lycos
Lycos indexes web pages (1.5 million +), web page titles, headings, subheadings, URLs, and significant text.
Search results are returned in a ranked order.

Magellan
Magellan indexes over 80,000 web sites. Search results are ranked and annotated.

Open Text Index
Indexes full text of approximately 1.3 million pages. Check out the Open Text Help pages for tips on using this search engine.

WebCrawler
Maintained by America Online, WebCrawler indexes over 200,000 pages on approximately 75,000 web servers. URLs, titles, and document content are indexed.

WWWW -- World Wide Web Worm
Approximately 250,000 indexed pages; indexed content includes hypertext, URLs, and document titles.

Yahoo
A favorite directory and search engine, Yahoo has organized over 80,000 Web sites (including newsgroups) into 14 broad categories. Yahoo also maintains a comprehensive list of links to Yahoo - Computers and Internet:Internet:World Wide Web: Searching the Web other web search engines, indexes, and guides.

Finally the internet is a huge source of information in all fields of knowledge.
Datum will take your hand through this incredible world of
information to get what you need in a fast, reliable
and professional way. 

Introduction to Computers

We are living in an information age dependent upon digital information. Digital information is electronic information, the result of computer processing. Every type of job relies upon getting information, using it, managing it, and relaying information to others. Computers enable the efficient processing and storage of information.

Do not think of a computer merely as the machine with the keyboard and the mouse, although that might be true for some types of computers. Embedded computers may be inside your household appliances, the VCR, the automobile, planes, trains, powerplants, water purification plants, calculators, and even inside a few toys. These embedded computers are very small. They affect our lives each day. Why, even modern traffic lights operate with computers. They are all around us. Think of additional ways in which computers affect our lives each day.


The Four Operations of a Computer System

Input

Home computers are microcomputers. Input is supplied to the microcomputer with the use of a keyboard, a mouse, or another input device. These input devices may be called peripheral devices.
Processing

Processing is done inside the computer in an area called the central processing unit (CPU). Processing is the conversion of input to output.
Storage

Storage refers to holding information somewhere.
RAM, Random Access Memory, is short-term memory. It is volatile memory because the memory is automatically "erased" when the power is turned off or interrupted. The RAM memory is located inside the computer case on the motherboard. A motherboard is not the keyboard. The keyboard is what you type with. A motherboard holds RAM memory, electronic circuits and other computer parts including the central processing unit. ROM, Read-Only-Memory, is not volatile meaning the memory is still there when power is interrupted or turned off. When the computer is turned back on again, ROM memory is still in storage on the internal hard disk.
Output

Output is the result of a computer process. Output may be viewed on a monitor screen, heard through speakers, printed on printers, and so forth. Output devices may be considered hardware and are also considered to be peripheral devices.

A Basic Computer "System"

A computer system refers to the computer AND all of its equipment. Equipment like speakers, printer, keyboard, scanner, etc. is called peripheral equipment, sometimes shortened to "peripherals". The central processing unit (CPU) is considered to be "the computer". Without peripheral equipment (such as monitor, printer, speakers, etc.) for input and output the microcomputer (home computer) will not be able to do anything you find useful.

Your computer system cannot help you type a letter unless you have some type of software (program) to do this. Most typing is handled by a "word processing" program. A software program for your computer can be purchased at stores like Office Depot, Staples, and computer stores. Check your local telephone directory for a computer store in your area. Sometimes when you purchase a computer it already has a word processing program installed. If you buy a computer from a large electronics chain store, even if you have to travel out of town, you will get a better price as a rule than buying from a smaller chain store in town. Ask in town first, if they would be willing to match another store's Advertised price... See "Buying A Computer", next.




Buying A Computer

It is best to ask and to compare features before you buy a computer. The first question to ask yourself is, "What do I want a computer to do?" Do you need it only for e-mail and a little light letter writing or do you need it for graphics and Web page authoring? Will you also want extra storage for your music files or graphics files? Do you need any hardware for game playing? What type of Internet connection will you have: dialup, cable, DSL, or other broadband connection? Will you be needing a computer for school work? Accounting? Make a list of what you need the computer to do before you talk to anyone about purchasing a computer. Your needs will be different that those of the next person. Visit Computer Company Web sites.




The PC vs. The Macintosh

There are several computer systems available for home computing but the two most common types of computers are the PC (personal computer), manufactured by companies such as DELL, IBM, NEC, GATEWAY, HP, SAMSUNG, and others -- and the Macintosh manufactured by Apple Computer.
The Macintosh Computer

The Macintosh computer is commonly referred to as a "Mac". Apple Computer has produced a PowerMac, an iMac, and a PowerMac G4, and the PowerMacG5. The operating system of the PowerMac G4 or G5 has undergone revisions. Each major version also has a name: OS X version 10.2.x is Jaguar; version 10.3.x is Panther, and the version 10.4.x is Tiger. The Apple PowerMac computers(the G4 and the G5) have two processors (for parallel processing) instead of just one, and there is space inside the computer to upgrade to 4 hard disks in a RAID array to give more power to the computers functioning as a server. Sometimes the computer tower is called a "box" which is a slang word for "the computer". You could say, "there are two processors inside the box."

There is software specially designed for the PowerMac computers to help move files from a Windows 98, ME, or 2000 system (XP is not listed on the box) to the Mac OS X. This software is called Move2Mac and is a product of Detto Technologies. I found my copy of the shrink-wrapped software on a shelf at a large Fry's Electronics store. A lot of computer software can be purchased using a credit card with a secure connection over the Web, then downloading that software to your own computer. I prefer having a CD or other disk with the software on the disk.

Downloading via FTP is the process of moving files from another computer over a network connection to a local computer (like your own home computer) using File Transfer Protocol (FTP). If working at school or on the job you have to get permission to download files, for security reasons. You can download files using a Mac or a PC computer. Both use File Transfer Protocol.

The Macintosh has excelled in the commercial graphics and publishing industries and thousands of people prefer a Mac for home use rather than a PC. The PC computers currently have a much greater market share and there are millions in use in homes and businesses throughout the world. When you attend college the college will specify which type of computer, Mac or PC, will be in use at the college for faculty and students. Some colleges use just Mac computers in campus buildings and for the faculty. Other colleges use PCs.

Each PC running a specific operating system such as Windows 2000 is able to use any software that says WIN95/98/NT/2000 on the box. The Windows2000 operating system can also run any software specified for WIN95/98/NT/2000 as well as any software specified as Windows 9.x/NT/2000. If in doubt about buying the correct software for your system, the store clerks will be happy to assist you if asked. If you are using Windows XP, make sure that the software you buy has Windows XP included in the "System Requirements", usually found on the side panel of the box for shrink-wrapped software (boxed software).

(In the following paragraphs I use OS to mean "operating system")
Prior to the Macintosh OS X operating system the Macs used an operating system based upon a single processor (computer CPU) which processed data and ran applications using what was called cooperative multitasking. Cooperative multitasking allowed programs to sometimes take control of the central processing unit. Now with the newer Macintosh operating system, OS 10.2.x (Jaguar) and later versions there is a UNIX-like kernel in the operating system, two processors and the central processing unit processes data with symmetric multiprocessing (uses both CPU's or "chips" to process data) and it uses preemptive multitasking, not allowing any application to take control of the central processing units.

If users want to run older software, the PowerMac G4 is a dual-booting machine meaning you can either boot into the older OS 9.2 or a version of OS X. (This is called "dual bootable".) Software written for the OS X (pronounced OS ten) will not run in the OS 9 environment but older legacy software is capable of being run while booted into the newer OS X, just that the newer features of the OS X will not be available when running applications designed for the OS 9 or older operating systems. The Mac G5's and newer versions of Os X have more multimedia features than the earlier G4's with the older versions of OS X. Get to the Apple Computer Web site for what's new now. The computer industry is not standing still... changes are rapid and one article online cannot capture what is now current.


Central Processing Unit and Software Compatibility

The computer processor inside a PC or PC-clone computer has totally different architecture (microscopic "wiring" schematic) inside the central processing unit chip (the CPU, or "chip"). In other words, the specific way the circuits are laid out in a computer chip (CPU, central processing unit) is called the chip architecture. PC chips and Mac chips have processing units with totally different architecture. Software is not interchangeable. Buy Mac software for the Macintosh and buy PC software for PC computers. An Apple or Mac computer is not a PC. Most PC Computers are sold new with a Windows operating system but keep in mind that other operating systems can also run on PC-architecture machines. One example of another operating system that can run on a PC machine is Linux for Windows. When two operating systems are on a disk they are installed on separate "partitions" of the disk. That is similar to two songs on one CD having to be on separate "tracks".


Hardware and Software

Usually, things you can see and touch on a computer or inside a computer are called "hardware" whereas programs for the computer (digital instructions) are called software. Software is created by a computer programmer who writes lines of code for the computer. An interpreter or compiler is a smaller program which changes the programmer's code into machine instructions for the central processing unit. After much testing and debugging, the programmer's code is finally "packaged" into executable files which make up the final "software" which can be purchased later, or might be "bundled" with the computer when you buy it (meaning that some software is already installed when you buy the computer.)

Introduction to Computer Softwares

Computer software (also computer program) is technically a set of instructions written in a computer language that solves a computational task. A computer program directs a computer to perform some processing function or combination of functions. For the instructions to be carried out, a computer must execute a program, that is, the computer reads the program, and then follows the steps encoded in the program in a precise order until completion. A program can be executed many different times, with each execution yielding a potentially different result depending upon the options and data that the user gives the computer.

Different kinds of computer software are designed to do a variety of tasks including word processing, number crunching, image and video editing, data storage, and home entertainment.

There are three major types of computer software:

System software

: it is used to run the computer hardware. It includes mainly the Operating system (OS), and device drivers.

Programming software

: usually provides tools to assist a programmer in writing computer programs and software using different programming languages.

Application software

Computer software works in a very unique way. First, the program has to be installed onto the computer using an installer program. The installation process copies all the necessary files needed to

After installing the program, the program can then be used by "loading" it into the computer's memory. Once the software is loaded, the computer is able to

A program should be "unloaded" from memory after use to allow other programs use the memory.

: allows end users to accomplish one or more specific (non-computer related) tasks. Typical applications include industrial automation, business software, educational software, medical software, databases, and computer games. run the program to the computer�s storage and may have to teach the OS how to run the program by altering or configuring the OS as required. The most common method of installing Software on a personal computer is by booting from a CD-ROM that contains the installation program and installable software. Such a CD can be burned execute the software. Computers operate by executing the computer program. This involves passing instructions from the application software, through the system software, to the hardware which ultimately receives the instruction as machine code. Each instruction causes the computer to carry out an operation which may include moving data, carrying out a computation, or altering the control flow of instructions.

The Operating System (System Software)

An operating system (OS) is a computer program that manages the hardware and software resources of a computer. At the foundation of all system software, the OS performs basic tasks such as controlling and allocating memory, prioritizing system requests, controlling input and output devices, facilitating networking, and managing files. It also may provide a graphical user interface for higher level functions.

Examples of OS�s include the Windows family of operating systems (Windows Vista, WindowsXP, Windows98, WindowsME, Windows95 etc), Linux family of operating systems (Obuntu, RedHat, Mandrake, SuSE etc), Solaris, and Unix.

The OS is the most important software because it is responsible for

booting the computer. Every computer must have an OS installed on it. The Windows family of OS�s are the most popular. An estimate of 9 out of every 10 computers runs Windows.

Windows operating systems

The term Windows collectively describes any or all of several generations of Microsoft (MS) operating system (OS) products.

The Microsoft Windows family of operating systems originated as a graphical layer on top of the older MS-DOS environment for the IBM PC. As of 2004, Windows held a near-monopoly of around 90% of the worldwide desktop market share, although some predict this to dwindle due to the increased interest in open source operating systems.

The first independent version of Microsoft Windows, version 1.0, released in November 1985, lacked a degree of functionality and achieved little popularity. Windows 1.0 did not provide a complete operating system; rather, it extended MS-DOS. Modern versions are based on the newer Windows NT core that first took shape in OS/2 and borrowed from OpenVMS. Windows runs on 32-bit and 64-bit Intel and AMD processors, although earlier versions also ran on the DEC Alpha, MIPS, and PowerPC architectures (some work was done to port it to the SPARC architecture).

In August 1995, Microsoft released Windows 95, which made further changes to the user interface and was the first Windows version to utilize multitasking.

In July 1993, Microsoft released Windows NT based on a new kernel. NT was considered to be the professional OS. NT and the Windows non-professional line would later be fused together to create Windows XP.

The next in line was Microsoft Windows 98 released in June 1998. Substantially criticized for its slowness compared with Windows 95, many of its basic problems were later rectified with the release of Windows 98 Second Edition in 1999.

As part of its professional line, Microsoft released Windows 2000 in February 2000. The consumer version following Windows 98 was Windows Me (Windows Millennium Edition). Released in September 2000, Windows Me attempted to implement a number of new technologies for Microsoft: most notably publicized was "Universal Plug and Play." However, the OS was substantially criticized for its lack of compatibility and stability.

In October 2001, Microsoft released Windows XP, a version built on the Windows NT kernel that also retained the consumer-oriented usability of Windows 95 and its successors. This new version was widely praised in computer magazines. It shipped in two distinct editions, "Home" and "Professional", the former lacking many of the superior security and networking features of the Professional edition. Additionally, the "Media Center" edition was released in 2003, with an emphasis on support for DVD and TV functionality including program recording and a remote control.

In April 2003, Windows Server 2003 was introduced, replacing the Windows 2000 line of server products with a number of new features and a strong focus on security; this was followed in December 2005 by Windows Server 2003 R2.

Windows Vista, the successor to Windows XP, is due to be released on January 30, 2007. It was released to business consumers on November 30, 2006. Windows Vista introduces a breakthrough user experience and is designed to help you feel confident in your ability to view, find, and organize information and to control your computing experience.

The visual sophistication of Windows Vista helps streamline your computing experience by refining common window elements so you can better focus on the content on the screen rather than on how to access it. The desktop experience is more informative, intuitive, and helpful. And new tools bring better clarity to the information on your computer, so you can see what your files contain without opening them, find applications and files instantly, navigate efficiently among open windows, and use wizards and dialog boxes more confidently.

Windows Server 2003's successor will be Windows Server "Longhorn", and has a planned release date in the second half of 2007.

Linux

Linux (also known as GNU/Linux) is a Unix-like computer operating system. It is one of the most prominent examples of open source development and free software; its underlying source code is available for anyone to use, modify, and redistribute freely.

Initially developed and used primarily by individual enthusiasts on personal computers, Linux has since gained the support of corporations such as IBM, Sun Microsystems, Hewlett-Packard, and Novell, Inc., and has risen to prominence as an operating system for servers; eight of the ten most reliable internet hosting companies now run Linux on their web servers.

Linux has been more widely ported to different computing platforms than any other operating system. It is used in devices ranging from supercomputers to mobile phones, and is gaining popularity in the personal computer market. Linux's roots in the Unix operating system mean that in addition to graphical configuration tools and control panels available for many system settings and services, plain-text configuration files are still commonly used to configure the OS and can readily be made accessible (or not) to users, at the administrator's will.

Linux is increasingly common as an operating system for supercomputers. For example, in the November 2005 TOP 500 list of supercomputers, seven of the top ten supercomputers in the world, including the two fastest, ran Linux. Of the 500 systems, 371 (74.2%) ran Linux.

Solaris

Solaris is a computer operating system developed by Sun Microsystems. It is certified against the Single UNIX Specification as a version of Unix. Although Solaris proper is still proprietary software, the core OS has been made into an open source project, Open Solaris

Solaris is considered to be the SunOS operating system plus a graphical user environment, ONC+, and other components. .

OpenSolaris was seeded on June 14, 2005 from the then-current Solaris development code base; both binary and source versions are currently downloadable and licensed without cost.

The underlying Solaris codebase has been under continuous development since work began in the late 1980s on what was eventually released as Solaris 2.0.

The Solaris version under development by Sun is codenamed Nevada, and is derived from what is now the OpenSolaris codebase.

Programming Software

Computer programmers are responsible for teaching computers how to perform tasks and solve computational problems. They develop the software that runs on computers using special software called a

A compiler is a computer program (or set of programs) that translates text written in a computer language (the source language) into another computer language (the target language).

A computer language is the language the computer understands and can interpret. There are two main types of computer languages the High level language and the Low level language or machine language. Since the computer is a machine, it understands the machine language. Unfortunately, the machine language is very difficult for human beings to understand, hence the need of a compiler.

Examples of computer languages include Pascal, Basic, Java, C-Sharp, and Prolog.

Overview of Application Software

This is the most interesting class of software. Different classes of software and their use shall be discussed.

Office Software

Microsoft Office is a software suite that consists of different software applications that complete different activities. The various software contained in Microsoft office are both for home use and for business. Microsoft Office is by far the most widely recognized software suite in the world with about 600 million users worldwide. Microsoft Office among many others include the following:

A Word processor

A word processor may also refer to a stand-alone computer unit similar to a typewriter, but often including technological advancements such as a screen, advanced formatting and printing options, and the ability to save documents onto memory cards or diskettes. Word processors almost invariably allowed the user to choose between standard typing and word processing modes by way of a switch. Such word processors should not be confused with an electric typewriter.

Word processors are descended from early text formatting tools (sometimes called text justification tools, from their only real capability). Word processing was one of the earliest applications for the personal computer in office productivity.

Microsoft Word is the most widely used computer word processing system. There are also many other commercial word processing applications, such as WordPerfect. Open-source applications such as OpenOffice's Writer and KWord are rapidly gaining in popularity.

: A word processor (more formally known as document preparation system) is a computer application used for the production (including composition, editing, formatting, and possibly printing) of any sort of printable material.

Word processing

batch mailings using a form letter template and an address database (also called mail merging);

indices of keywords and their page numbers;

tables of contents with section titles and their page numbers;

tables of figures with caption titles and their page numbers;

cross-referencing with section or page numbers;

footnote numbering

Other word processing functions include "spell checking" (actually checks against wordlists), "grammar checking" (checks for what seem to be simple grammar errors), and a "thesaurus" function (finds words with similar or opposite meanings). In most languages grammar is very complex, so grammar checkers tend to be unreliable and also require a large amount of memory.

typically refers to text manipulation functions such as automatic generation of:

A Spreadsheet

Once you have defined the cells and the formulas for linking them together, you can enter your data. You can then modify selected values to see how all the other values change accordingly. This enables you to study various what-if scenarios.

A simple example of a useful spreadsheet application is one that calculates mortgage payments for a house. You would define five cells:

1. total cost of the house

2. down payment

3. mortgage rate

4. mortgage term

5. monthly payment

Once you had defined how these cells depend on one another, you could enter numbers and play with various possibilities. For example, keeping all the other values the same, you could see how different mortgage rates would affect your monthly payments.

There are a number of spreadsheet applications on the market, Excel being among the most famous. The more powerful spreadsheet applications support graphics features that enable you to produce charts and graphs from the data.

Most spreadsheet applications are multidimensional, meaning that you can link one spreadsheet to another. A three-dimensional spreadsheet, for example, is like a stack of spreadsheets all connected by formulas. A change made in one spreadsheet automatically affects other spreadsheets.

With Microsoft Excel, you can create detailed spreadsheets for viewing and collaboration. Create customized formulas for your data and analyze it with easy to construct charts.

: Spreadsheet applications (sometimes referred to simply as spreadsheets) are computer programs that let you create and manipulate spreadsheets electronically. A spreadsheet is a table of values arranged in rows and columns. Each value can have a predefined relationship to the other values. If you change one value, therefore, you may need to change other values as well. In a spreadsheet application, each value sits in a cell. You can define what type of data is in each cell and how different cells depend on one another. The relationships between cells are called formulas, and the names of the cells are called labels.

Microsoft PowerPoint

provides a complete set of tools for creating powerful presentations. Organize and format your material easily, illustrate your points with your own images or clip art, and even broadcast your presentations over the web.

Microsoft Access

gives you powerful new tools for managing your databases. Share your database with co-workers over a network, find and retrieve information quickly, and take advantage of automated, pre-packaged wizards and solutions to quickly create databases.

Graphic application software

This is a class of software used for creating and editing images. They are mainly used in manipulating images and for creating special graphic effects used in making banners, calendars, tee-shirts etc. A general name for graphic and text creation and manipulation is

Corel draw interface

Desktop Publishing. The CorelDRAW Graphics Suite is popular software in this class.

Engineering application software

This is a class of software used by various specialists in achieving a high degree of accuracy and precision. They are used for Computer Aided Design (CAD). Popular software that fall into this category are AutoCAD and Electronic workbench.

AutoCAD is a suite of CAD software products for 2- and 3-dimensional design and drafting. Modern AutoCAD includes a full set of basic solid modeling and 3D tools.

Electronic workbench is CAD software used in designing, testing, and simulating electronic circuits.

Environmental Science Application Software

These are software that can be applied to the environment as a whole. In the area such as the oil industry there are software for monitoring of oil rigs. The operator does not have to go to the site to monitor the rigs

Medical and Agricultural software

This software is used in the field of medicine and agricultural science. They help to make work easier in the field in which the software is applied. For example in the medical field during surgery the software has been designed to simulate the operation to be carried out for surgeons and waits for a confirmation from the computer that he or she is eligible or ready to perform the operation on the patient. Just like we play our car race games on a play station. Likewise we also have software programs for agricultural science. The motive behind these software is to avoid risk that occur during operation in a real life scenario. Also the software can be used for educative purposes.

Software Legal Issues

Software is regarded as intellectual property. Just like a book or music it must be respected and treated as such. This means that the permission of the creator must be sought before use or distribution. The �terms and conditions of use� are usually expressed in a license agreement (End User License Agreement, EULA) which is a legal document that is binding between the creator and the user of software.

Different licensing schemes exist for using software.

Proprietary

software are software developed for the purpose of making profit and are usually very expensive.

Open source

software are software that are normally free but may require a low fee for support services.

Freeware

are computer programs given away free of charge.

Shareware

are computer software that is distributed free of charge but is usually accompanied by a request for a small payment from satisfied users to cover costs and registration for documentation and program updates.

OVERVIEW OF PROPRIETARY SOFTWARE

Proprietary software is software that has restrictions on using and copying it, usually enforced by a proprietor. The term's literal meaning covers software that has an owner who exercises control over what users can do with it. The adjective "proprietary" also avoids confusion with the phrase "commercial software", since free software can also be sold and used for commercial purposes. The risk involved with proprietary software is that if for any reason the proprietor ceases, or decides to cease, or limit production or support for a proprietary software product, previous licensees can be left at a disadvantage and have no recourse if problems are found with the software. The proprietor uses a temporary monopoly with copyright and sometimes software patents that can make the software more expensive. A dependency on future versions and upgrades can make the monopoly permanent without the emergence of a competing software package.

Well known examples of proprietary software include Microsoft Windows, RealPlayer, Adobe Photoshop, Mac OS, WinZip and some versions of UNIX.

Some free software packages are available under proprietary terms. Examples include MySQL, Sendmail and SSH. The original copyright holders for a work of free software, even copyleft free software, can use dual-licensing to allow themselves or others to redistribute proprietary versions. Non-copyleft free software, or free software "with a permissive license", allows anyone to make proprietary redistributions.

Some proprietary software comes with source code or provides offers to the source code. Users are free to use and even study and modify the software in these cases, but are restricted by either licenses or non-disclosure agreements

from redistributing modifications or sharing the software. Examples include Pine, the Microsoft Shared source license program, and certain proprietary implementations of SSH.

Shareware, like freeware, is proprietary software available at zero price, but differs in that it is free only for a trial period, after which some restriction is imposed � for example, it is completely disabled.

The prevention of use, copying, or modification can be achieved by legal or technical means. Technical means include releasing machine-readable binaries only and withholding the human-readable source code. Legal means can involve software licensing, copyright, and patent law. Proprietary software can be sold for money as commercial software or available at zero-price as freeware.

Overview of Open Source

Open-source software is computer software whose source code is available under a copyright license that permits users to study, change, and improve the software, and to redistribute it in modified or unmodified form. It is the most prominent example of open source development.

In 1998, a group of individuals advocated that the term free software be replaced by open-source software (OSS) as an expression which is less ambiguous and more comfortable for the corporate world. Software developers may want to publish their software with an open-source software license, so that anybody may also develop the same software or understand how it works. Open-source software generally allows anybody to make a new version of the software, port it to new operating systems and processor architectures, share it with others or market it. The aim of open source is to let the product be more understandable, modifiable, duplicatable, reliable or simply accessible, while it is still marketable.