Computer basic for beginner and everyone who don't know how to use computer.And more information about computer i.e. network, software, hardware etc.
If you take a bit of care, you should never have to worry about returning the laptop in anything but pristine condition.
1. Backup, backup backup! Backing up your data just means saving your files to a separate location (like a cd, floppy or zip disk) so in event of disaster you can easily copy your files back onto your computer. How often really depends on you. Just ask yourself, "If I only back up once every 3 months, would anything I saved on my hard drive since the last time I saved it on a backup be allright if I could NEVER get it back?"
2. Invest in an UPS (uninterruptible power source). A UPS is a wonderful device that works as a surge protector and a battery backup all in one! Not only does it keep your computer safe from electrical spikes that can be traveling through the lines, it also gives you time to save your work, and properly power down your computer in event of a power failure. You don't lose your work, and your computer gets to be shut down properly.
3. Never turn the computer off with the power switch. The one exception to this rule is when your computer locks up and your hard drive is not running (the hard drive light is not blinking). In this situation, you can turn the power off without harmful effects to the hard drive. As cutting the power can also result in lost data or Windows files, you should only do this when you have to.
Doing this can help prevent permanent hard drive damage caused by the hard drive heads contacting the surface of the drive disc. This can prevent a host of Windows problems.
Whenever possible, recover from crashes by pressing the Ctrl + Alt + Delete keys at the same time and going into your Task Manager. You can often find programs that are not responding in here, and chose to close them from this utility. Press Clt + Alt + Delete again to reboot your computer from this screen.
4. Scan disk and defrag once a month. These utilities help to keep your hard drive in optimal shape and error free.
5. Do not unplug peripheral devices while the power is turned on. Unplugging devices such as your mouse, keyboard, printer etc with the power on can short out the connector socket or even the motherboard itself.
The only time you would unplug something while the power is on, is if the device is hot swappable/pluggable. If you are unsure if something is hot swappable or not, power down first to play it safe.
6. Remove programs from your startup. Often when you install a program, it will ask you whether it should load up as soon as Windows loads (or just decide to do so on its own). The more programs you have trying to start up at the same time, the slower your computer will start. Also, all those programs running in the background while you try to work will slow your computer's response time.
In windows 98, ME, and XP, you can do this by going to your Start -> Run -> in the command box type in 'msconfig' and a small window will appear. Go to the tab marked "Startup" and you can chose what items to remove from there.
In Windows 2000, you can do this by going to your Control Panel -> Administrative Services -> Services.
7. Run virus checks and adware/spyware scans regularly (at least once a week). There are so many types and variations of viruses, spyware and adware floating around that at times it may seem daunting to even have internet access on your computer. However, regular scans with your virus scanner, and adware scanners, can ensure your computer remains healthy.
8. Keep disks handy. If the worst thing happens, and you need to format your system for one reason or another, then it is a good idea to have all your driver disks, operating system disks, backup disks and so forth in a readily available place. Running around in a panic at the 11th hour because you cannot remember where the drivers are for your network card, is not a good place to be.
9. Keep your software updated. Software developers are always writing and releasing patches that update the software you have already bought from them. A lot of these patches fix problems you may be experiencing yourself with a particular program.
Other patches plug security leaks. Still other patches update reference files for your virus/spy/adware scanners to make sure you are scanning for as many variants as possible. So make sure you regularly update/patch your operating system, virus scanners, and various other applications!
10. Develop a schedule of maintenance practices. All this advice is meaningless if you keep forgetting to do it, or only remember after something has gone wrong. Write yourself up a maintenance schedule, with a list of what tasks should be performed daily, weekly, and monthly.
If you develop a routine and stick to it, then you should avoid the larger problems by always being on top of the smaller ones!
There are many reasons to replace your computers before they could reasonably be called old. Big corporations may replace their computers every three years or less. I usually recommend that nonprofits replace their computers every four years. One reason to do this is so computers are replaced before they fail, so that down-time can be scheduled instead of being caused by unexpected failure. Productivity increases with newer computers, as people spend less time waiting for programs to open and respond to commands.
Newer computers have newer technology, which means improved security, stability, and new features. Or maybe there is a new software package you want to use -- and your old computer doesn't meet the system requirements.
But there are good reasons to keep old computers around. Maybe you just don't have the money to buy a new one. Or you may be in a part of the world where replacement computers are not only expensive -- they're hard to come by. Or maybe you want to wait as long as possible before sending the lead, mercury, and other toxic materials in your computer into the environment, and using more resources to build a new computer that you may not yet need.
For any of these reasons, you might want to keep your old computer running well, even if it is four, five, or six years old.
(If you're interested in keeping older Macs running, read "Resources for Older Computers" on TechSoup.)
Extending the Usable Life of a Computer
As computers get older, different things can go wrong. You may experience problems with the software, the operating system may respond sluggishly, or you may receive error messages. Maybe you can't open a program, or it crashes unexpectedly. You may also run into hardware problems: the CD-ROM drive won't open, your floppy drive won't reliably read disks, or your modem just stops working.
To extend the life span of a computer, consider what can go wrong, how to prevent and recover from those problems, and how to change the way you use your computer:
What Can Go Wrong with Software?
Problem: Too Much Software
The biggest software problem on old computers is that there is too much of it. When a computer has been in an office for a long time, it tends to accumulate software like the junk drawer in your kitchen. Having too much software can cause a variety of problems.
Unnecessary software can take up too much room on the hard drive. If the hard drive is completely full or nearly full, the operating system won't run well. On a newer computer, having lots of software is less of a problem because new hard drives tend to be big. But on an old computer with a small hard drive, your system may respond sluggishly.
In addition, as programs are added to a computer, they may take up more of its memory. Some programs, particularly little ones downloaded from the Internet, stay active in your system's RAM even when you're not using them in order to open more quickly when you do want to use them. In Windows, these "memory resident" applications can often be seen in the system tray in the lower right-hand corner of the screen. In Mac OS 9, you might have extensions taking up memory that really aren't needed. On a newer computer with RAM to spare, lots of memory resident applications may not be a big deal. But on an old computer with little RAM, you should free up as much memory as possible.Solution: Remove Unnecessary Software
First, decide what software is necessary. Consider the difference between "need" and "want." Be ruthless. You may want iTunes so you can listen to streaming audio while you work, but do you need it? Old computers can't afford such luxuries; only keep what you really need to do your work.
In Windows, go to the Add/Remove Programs control panel. Determine for certain which software applications you don't need. If you're not sure, make certain that you have the original installation disks so you can reinstall if necessary. Then uninstall the software you don't need.
If software you do need shows up in the system tray, you may be able to disable its tendency to always stay open. For example, in Microsoft Windows you may see the icon for MSN Messenger in your system tray. In the options for the program you can set it not to launch automatically when the computer starts up. This will free up some memory for other purposes.
In Mac OS 9, open the Extensions Manager and disable extensions you don't need. If you don't know what you need and what you don't, consult with an expert.
Problem: New Software, Old Hardware
It's a sad fact, but you can't install just any software on any computer. For example, let's say you have a Pentium II with 128 MB of RAM running Windows 2000. If you use the right software, you won't have problems with this set-up. But if you install the latest version of Photoshop, it just won't work. I frequently find older computers with installed with software that just won't work well -- such as Mac OS X on an original bondi blue iMac. Even if you can install it, that doesn't mean it will run well.
Solution: Stay Within Your Limits
Before installing any new software, check the system requirements. Make sure that it is not more than your computer can handle. Make sure you have enough room on the hard drive and that it is compatible with the operating system you're running. If the software needs more than you're able to provide in terms of system resources, don't install it.
But what if you need to add software to your older computer? For example, let's say you want to add Microsoft Access to a computer in order to open a database. When you go to TechSoup Stock, you find that your nonprofit is eligible to order a donated copy of Microsoft Office Professional, which includes Microsoft Access. But wait -- they only offer Office 2003, which has high system requirements. What to do? You could upgrade your hardware to meet the system requirements (more on that later), or you could pick an earlier version of the software -- say, Office XP.
"But Office XP isn't available through TechSoup Stock!" you wail. I'll let you in on a little secret. When you obtain a software license for Microsoft products through TechSoup Stock, that license entitles you to use older versions of the software. I know this is a little confusing; the point is, eligible organizations can obtain older versions of Microsoft products through TechSoup Stock. (Read more about the process on TechSoup Stock -- although the instructions refer to Windows XP, it works for other Microsoft software, too.) If you're not eligible to order donated software through TechSoup Stock, you may be able to order discounted software from an Open Charity License reseller -- this principle applies to these licenses, too. You can buy Office 2003 and install Office XP.
This act of buying new software but installing older software is sometimes called "downgrading." The rules vary from vendor to vendor, so do some research before assuming you can downgrade.
Problem: Spyware
This is mostly a problem with Windows. Spyware, adware, and other junk software on your computer is always undesirable, regardless of the age of your computer. But again, on an old computer every bit of memory is precious. You cannot allow these invasive programs to steal your valuable system resources.Solution: Spyware Removal Tool
Use a spyware removal tool such as Spybot Search and Destroy or Ad Aware. A nice feature of Spybot is that it can "innoculate" your computer against future infections. Best of all, it's free. Read more about removing malware on TechSoup.
Problem: Viruses
As with spyware, this problem mostly affects Windows users. (There just aren't that many viruses for the Mac OS.) Viruses are a problem with computers new and old, but they are more likely to turn up on old computers. This is simply because an old computer has been around longer, so it has a greater chance of being infected with a virus. There's also a greater chance users have lapsed on upgrading anti-virus software.
Solution: Anti-Virus Software
If you're going to run an old computer, you have to keep it clean if you expect it to perform. That means having up-to-date anti-virus software.
Preventing Problems with Software
Performing regular maintenance will forestall problems with your operating system and other software. That means installing updates from the software vendor, defragmenting the hard drive, running Scandisk on Windows 98 or chkdsk on Windows 2000 or Windows XP. Be prudent about installing only what you need to do your work. Don't install software just for fun. Ultimately, you'll be a lot happier if your computer is running well.
What Can Go Wrong with Hardware?
There's basically only one thing that goes wrong with hardware: it breaks. If it's not broken, the problem isn't with the hardware. By "broken," I mean worn out, bent, burned up, cracked, smashed, or otherwise inoperable.
So what can break? Just about anything in your computer can break, but the parts that move are more likely to break:
If something appears to be broken, first determine whether it's actually broken. I won't go into detail here on troubleshooting hardware, but suffice to say that cracking open the mouse and cleaning the dust bunnies out of the rollers can make a "broken" mouse work like new.
Preventing Mechanical Hardware Problems
You can help keep moving parts running by using them gently and removing sources of friction. The biggest source of friction is dust, including hair and cigarette ashes.
Keeping your work area clean will prolong the life of your computer. Dust your desk regularly. Vaccuum the floor to reduce the amount of dirt there. Don't smoke in your office: you already know it's not good for you or your coworkers, and now you know it's not good for your computer. Once a year or so, open your computer's case and blow out any dust with a can of compressed air.
Preventing Electrical Hardware Problems
Power surges can break electronics. Test your electrical outlets to see if they are properly grounded, and use a good-quality surge protector to protect your equipment from voltage spikes. Dusting out computers also helps lower their temperature, which improves performance and prolongs the life of electrical components.
Upgrading Hardware
If you're upgrading on a budget, you may be able to get used parts for free or for cheap from a computer recycling organization.
Changing Hardware Roles
If a computer is too old to be servicable as a desktop computer for one purpose, you may yet find a use for it.
Changing Operating Systems
One of the best ways to bring new life to an old PC is to erase it and start over with some version of Linux. Some Linux distributions such as Cobind are specifically intended for use on older hardware. Cobind Linux has many features of a modern operating system. Like all versions of Linux, it is unbelievably stable and highly secure. Cobind will run well on a Pentium II 300MHz processor with 64MB of RAM and a 2GB hard drive.
Changing Paradigms
Old computers can make excellent terminals in a thin-client network. In your standard small office environment, programs are run on separate computers: I might run an e-mail program on my computer, while you run a database on your computer. In a thin-client network, all programs are run on one computer, which is connected to many terminals so that multiple users can access that one computer system at once. So instead of replacing old computers with new ones, an organization could use a single higher powered machine as a terminal server, and use the old PCs as terminals. A terminal in a set-up like this doesn't need a hard drive, much of a processor, or memory. It doesn't do any processing at all -- it just provides a window onto the terminal server.
Depending on the applications that staff need to run, an organization could use the same old Pentium II PCs for years. The only reason to finally remove them from service would be hardware failure.
Many legitimate advertisers on the Internet use windows that pop up in the middle of your screen to display a message. They might also open when you click a link or button on a Web site, and they might open either over or under the window you wish to view. Some pop-ups are helpful. For example, if you click an image to see a larger version, it might open in a pop-up window. Unfortunately, some pop-up windows can contain inappropriate content or can be a way for you to accidentally download dangerous software (called spyware or adware) onto your computer.
With Windows XP Service Pack 2 (SP2) Internet Explorer allows you to prevent most pop-up windows from appearing over pages you want to view while you're using the Internet.
When you install SP2, Pop-up Blocker is turned on in Internet Explorer and set to the medium setting, which means it will block most automatic pop-ups. The default settings for the pop-up blocker allow you to see pop-ups that are opened when you click a link or button on a Web site. Pop-up Blocker will also play a sound and show the Information Bar when a pop-up is blocked. You can adjust these settings so that Pop-up Blocker works the way you want it to.
To change Pop-up Blocker settings
1. | Open Internet Explorer. |
2. | On the Tools menu, point to Pop-up Blocker, and then click Pop-up Blocker Settings. |
If you want to see pop-up windows from a specific Web site, type the address (or URL) of the site in the Address of Web site to allow box, and then click Add.
Tip To temporarily allow a site to display pop-ups, click the Information Bar when it notifies you that a pop-up has been blocked. Then click Temporarily Allow Pop-ups.
To block pop-ups even if they are launched when you click a link or button on a Web site
1. | Open Internet Explorer. |
2. | On the Tools menu, point to Pop-up Blocker, and then click Pop-up Blocker Settings. |
3. | Select the High setting in the box near the bottom of the dialog box. |
Note If you want to see pop-ups that are blocked when you have this setting turned on, hold down the CTRL key while the window opens.
If you've installed SP2 and you still see pop-ups in Internet Explorer, try the possible solutions below.
• | Make sure Pop-up Blocker is turned on: Pop-up Blocker is turned on by default, but someone may have turned it off. |
To turn on Pop-up Blocker
1. | On the Tools menu, point to Pop-up Blocker. |
2. | Click Turn on Pop-up Blocker. |
• | Rid your system of spyware: If you get similar pop-up windows no matter what sites you visit or even if you're not on the Web at all, you could have spyware, adware, or other software on your computer that's launching pop-ups. To stop these pop-ups, you will have to identify the software, then remove it or change its settings to stop it from launching pop-ups. To learn more about this read How to Protect Your Computer from Spyware and Adware. |
• | Some windows are not blocked: Pop-up Blocker is smart enough to not block pop-up windows that you open deliberately by clicking a link—for example, if you were on a travel reservation site and you clicked a link to open a pop-up window containing your confirmation details, this pop-up window would not be blocked because you opened it intentionally. Also, Pop-up Blocker will not block some pop-ups with certain types of animated content or pop-ups from Web sites that are in two Web content zones: Local intranet or Trusted sites. To learn more about security zones, see Working with Internet Explorer 6 Security Settings. |
Summary: TCP and IP were developed by a Department of Defense (DOD) research project to connect a number different networks designed by different vendors into a network of networks (the "Internet"). It was initially successful because it delivered a few basic services that everyone needs (file transfer, electronic mail, remote logon) across a very large number of client and server systems. Several computers in a small department can use TCP/IP (along with other protocols) on a single LAN. The IP component provides routing from the department to the enterprise network, then to regional networks, and finally to the global Internet. On the battlefield a communications network will sustain damage, so the DOD designed TCP/IP to be robust and automatically recover from any node or phone line failure. This design allows the construction of very large networks with less central management. However, because of the automatic recovery, network problems can go undiagnosed and uncorrected for long periods of time.
As with all other communications protocol, TCP/IP is composed of layers:
The Army puts out a bid on a computer and DEC wins the bid. The Air Force puts out a bid and IBM wins. The Navy bid is won by Unisys. Then the President decides to invade Grenada and the armed forces discover that their computers cannot talk to each other. The DOD must build a "network" out of systems each of which, by law, was delivered by the lowest bidder on a single contract.
The Internet Protocol was developed to create a Network of Networks (the "Internet"). Individual machines are first connected to a LAN (Ethernet or Token Ring). TCP/IP shares the LAN with other uses (a Novell file server, Windows for Workgroups peer systems). One device provides the TCP/IP connection between the LAN and the rest of the world.
To insure that all types of systems from all vendors can communicate, TCP/IP is absolutely standardized on the LAN. However, larger networks based on long distances and phone lines are more volatile. In the US, many large corporations would wish to reuse large internal networks based on IBM's SNA. In Europe, the national phone companies traditionally standardize on X.25. However, the sudden explosion of high speed microprocessors, fiber optics, and digital phone systems has created a burst of new options: ISDN, frame relay, FDDI, Asynchronous Transfer Mode (ATM). New technologies arise and become obsolete within a few years. With cable TV and phone companies competing to build the National Information Superhighway, no single standard can govern citywide, nationwide, or worldwide communications.
The original design of TCP/IP as a Network of Networks fits nicely within the current technological uncertainty. TCP/IP data can be sent across a LAN, or it can be carried within an internal corporate SNA network, or it can piggyback on the cable TV service. Furthermore, machines connected to any of these networks can communicate to any other network through gateways supplied by the network vendor.
Each technology has its own convention for transmitting messages between two machines within the same network. On a LAN, messages are sent between machines by supplying the six byte unique identifier (the "MAC" address). In an SNA network, every machine has Logical Units with their own network address. DECNET, Appletalk, and Novell IPX all have a scheme for assigning numbers to each local network and to each workstation attached to the network.
On top of these local or vendor specific network addresses, TCP/IP assigns a unique number to every workstation in the world. This "IP number" is a four byte value that, by convention, is expressed by converting each byte into a decimal number (0 to 255) and separating the bytes with a period. For example, the PC Lube and Tune server is 130.132.59.234.
An organization begins by sending electronic mail to Hostmaster@INTERNIC.NET requesting assignment of a network number. It is still possible for almost anyone to get assignment of a number for a small "Class C" network in which the first three bytes identify the network and the last byte identifies the individual computer. The author followed this procedure and was assigned the numbers 192.35.91.* for a network of computers at his house. Larger organizations can get a "Class B" network where the first two bytes identify the network and the last two bytes identify each of up to 64 thousand individual workstations. Yale's Class B network is 130.132, so all computers with IP address 130.132.*.* are connected through Yale.
The organization then connects to the Internet through one of a dozen regional or specialized network suppliers. The network vendor is given the subscriber network number and adds it to the routing configuration in its own machines and those of the other major network suppliers.
There is no mathematical formula that translates the numbers 192.35.91 or 130.132 into "Yale University" or "New Haven, CT." The machines that manage large regional networks or the central Internet routers managed by the National Science Foundation can only locate these networks by looking each network number up in a table. There are potentially thousands of Class B networks, and millions of Class C networks, but computer memory costs are low, so the tables are reasonable. Customers that connect to the Internet, even customers as large as IBM, do not need to maintain any information on other networks. They send all external data to the regional carrier to which they subscribe, and the regional carrier maintains the tables and does the appropriate routing.
New Haven is in a border state, split 50-50 between the Yankees and the Red Sox. In this spirit, Yale recently switched its connection from the Middle Atlantic regional network to the New England carrier. When the switch occurred, tables in the other regional areas and in the national spine had to be updated, so that traffic for 130.132 was routed through Boston instead of New Jersey. The large network carriers handle the paperwork and can perform such a switch given sufficient notice. During a conversion period, the university was connected to both networks so that messages could arrive through either path.
Although the individual subscribers do not need to tabulate network numbers or provide explicit routing, it is convenient for most Class B networks to be internally managed as a much smaller and simpler version of the larger network organizations. It is common to subdivide the two bytes available for internal assignment into a one byte department number and a one byte workstation ID.
The enterprise network is built using commercially available TCP/IP router boxes. Each router has small tables with 255 entries to translate the one byte department number into selection of a destination Ethernet connected to one of the routers. Messages to the PC Lube and Tune server (130.132.59.234) are sent through the national and New England regional networks based on the 130.132 part of the number. Arriving at Yale, the 59 department ID selects an Ethernet connector in the C& IS building. The 234 selects a particular workstation on that LAN. The Yale network must be updated as new Ethernets and departments are added, but it is not effected by changes outside the university or the movement of machines within the department.
Every time a message arrives at an IP router, it makes an individual decision about where to send it next. There is concept of a session with a preselected path for all traffic. Consider a company with facilities in New York, Los Angeles, Chicago and Atlanta. It could build a network from four phone lines forming a loop (NY to Chicago to LA to Atlanta to NY). A message arriving at the NY router could go to LA via either Chicago or Atlanta. The reply could come back the other way.
How does the router make a decision between routes? There is no correct answer. Traffic could be routed by the "clockwise" algorithm (go NY to Atlanta, LA to Chicago). The routers could alternate, sending one message to Atlanta and the next to Chicago. More sophisticated routing measures traffic patterns and sends data through the least busy link.
If one phone line in this network breaks down, traffic can still reach its destination through a roundabout path. After losing the NY to Chicago line, data can be sent NY to Atlanta to LA to Chicago. This provides continued service though with degraded performance. This kind of recovery is the primary design feature of IP. The loss of the line is immediately detected by the routers in NY and Chicago, but somehow this information must be sent to the other nodes. Otherwise, LA could continue to send NY messages through Chicago, where they arrive at a "dead end." Each network adopts some Router Protocol which periodically updates the routing tables throughout the network with information about changes in route status.
If the size of the network grows, then the complexity of the routing updates will increase as will the cost of transmitting them. Building a single network that covers the entire US would be unreasonably complicated. Fortunately, the Internet is designed as a Network of Networks. This means that loops and redundancy are built into each regional carrier. The regional network handles its own problems and reroutes messages internally. Its Router Protocol updates the tables in its own routers, but no routing updates need to propagate from a regional carrier to the NSF spine or to the other regions (unless, of course, a subscriber switches permanently from one region to another).
IBM designs its SNA networks to be centrally managed. If any error occurs, it is reported to the network authorities. By design, any error is a problem that should be corrected or repaired. IP networks, however, were designed to be robust. In battlefield conditions, the loss of a node or line is a normal circumstance. Casualties can be sorted out later on, but the network must stay up. So IP networks are robust. They automatically (and silently) reconfigure themselves when something goes wrong. If there is enough redundancy built into the system, then communication is maintained.
In 1975 when SNA was designed, such redundancy would be prohibitively expensive, or it might have been argued that only the Defense Department could afford it. Today, however, simple routers cost no more than a PC. However, the TCP/IP design that, "Errors are normal and can be largely ignored," produces problems of its own.
Data traffic is frequently organized around "hubs," much like airline traffic. One could imagine an IP router in Atlanta routing messages for smaller cities throughout the Southeast. The problem is that data arrives without a reservation. Airline companies experience the problem around major events, like the Super Bowl. Just before the game, everyone wants to fly into the city. After the game, everyone wants to fly out. Imbalance occurs on the network when something new gets advertised. Adam Curry announced the server at "mtv.com" and his regional carrier was swamped with traffic the next day. The problem is that messages come in from the entire world over high speed lines, but they go out to mtv.com over what was then a slow speed phone line.
Occasionally a snow storm cancels flights and airports fill up with stranded passengers. Many go off to hotels in town. When data arrives at a congested router, there is no place to send the overflow. Excess packets are simply discarded. It becomes the responsibility of the sender to retry the data a few seconds later and to persist until it finally gets through. This recovery is provided by the TCP component of the Internet protocol.
TCP was designed to recover from node or line failures where the network propagates routing table changes to all router nodes. Since the update takes some time, TCP is slow to initiate recovery. The TCP algorithms are not tuned to optimally handle packet loss due to traffic congestion. Instead, the traditional Internet response to traffic problems has been to increase the speed of lines and equipment in order to say ahead of growth in demand.
TCP treats the data as a stream of bytes. It logically assigns a sequence number to each byte. The TCP packet has a header that says, in effect, "This packet starts with byte 379642 and contains 200 bytes of data." The receiver can detect missing or incorrectly sequenced packets. TCP acknowledges data that has been received and retransmits data that has been lost. The TCP design means that error recovery is done end-to-end between the Client and Server machine. There is no formal standard for tracking problems in the middle of the network, though each network has adopted some ad hoc tools.
There are three levels of TCP/IP knowledge. Those who administer a regional or national network must design a system of long distance phone lines, dedicated routing devices, and very large configuration files. They must know the IP numbers and physical locations of thousands of subscriber networks. They must also have a formal network monitor strategy to detect problems and respond quickly.
Each large company or university that subscribes to the Internet must have an intermediate level of network organization and expertise. A half dozen routers might be configured to connect several dozen departmental LANs in several buildings. All traffic outside the organization would typically be routed to a single connection to a regional network provider.
However, the end user can install TCP/IP on a personal computer without any knowledge of either the corporate or regional network. Three pieces of information are required:
In the case of the PCLT server, the IP address is 130.132.59.234. Since the first three bytes designate this department, a "subnet mask" is defined as 255.255.255.0 (255 is the largest byte value and represents the number with all bits turned on). It is a Yale convention (which we recommend to everyone) that the router for each department have station number 1 within the department network. Thus the PCLT router is 130.132.59.1. Thus the PCLT server is configured with the values:
The subnet mask tells the server that any other machine with an IP address beginning 130.132.59.* is on the same department LAN, so messages are sent to it directly. Any IP address beginning with a different value is accessed indirectly by sending the message through the router at 130.132.59.1 (which is on the departmental LAN).
Install high priority updates
Microsoft Update is the online extension of Windows that helps you keep your computer up-to-date. Microsoft Update includes updates from Windows Update and from Office Update, in addition to updates for other Microsoft products and for third-party device drivers. Use Microsoft Update to install updates for your computer’s operating system, software, and hardware.
New content is added to the site regularly so that you can obtain recent updates and fixes to help protect your computer and to keep it running smoothly. To use the Microsoft Update site to install all critical updates for your computer, follow these steps:
1. Connect to the Internet, and then start Windows Internet Explorer.
2. On the Tools menu, click Windows Update.
3. If Microsoft Update is not installed, click Microsoft Update. Otherwise, go to step 7.
4. On the Try Microsoft Update today Web page, click Start Now, and then click Continue on the Review the license agreement Web page.
5. In the Security Warning dialog box, click Install to install Microsoft Update.
6. On the Welcome to Microsoft update Web page, click Check for Updates
7. On the Keep your computer up to date Web page, click Express to install high priority updates.
8. On the Review and Install Updates Web page, click Install Updates, and then follow the instructions on the screen to complete the installation.
9. After you install the high priority updates, you can repeat these steps to install other updates. To do this, click Custom on the Keep your computer up to date Web page. Then, you can select updates from the sections that are listed on the navigation pane.
Programming languages provide various ways of specifying programs for computers to run. Unlike natural languages, programming languages are designed to permit no ambiguity and to be concise. They are purely written languages and are often difficult to read aloud. They are generally either translated into machine language by a compiler or an assembler before being run, or translated directly at run time by an interpreter. Sometimes programs are executed by a hybrid method of the two techniques. There are thousands of different programming languages—some intended to be general purpose, others useful only for highly specialized applications.
Computers take many physical forms. Early electronic computers were the size of a large room, consuming as much power as several hundred modern personal computers.[1] Today, computers can be made small enough to fit into a wrist watch and be powered from a watch battery. Society has come to recognize personal computers and their portable equivalent, the laptop computer, as icons of the information age; they are what most people think of as "a computer". However, the most common form of computer in use today is by far the embedded computer. Embedded computers are small, simple devices that are often used to control other devices—for example, they may be found in machines ranging from fighter aircraft to industrial robots, digital cameras, and even children's toys.
The ability to store and execute programs makes computers extremely versatile and distinguishes them from calculators. The Church–Turing thesis is a mathematical statement of this versatility: Any computer with a certain minimum capability is, in principle, capable of performing the same tasks that any other computer can perform. Therefore, computers with capability and complexity ranging from that of a personal digital assistant to a supercomputer are all able to perform the same computational tasks as long as time and storage capacity are not considerations.
Some newsgroups are moderated, others are not. If it is moderated a human moderator screens all messages and decides if these are worth posting. Discussions can be "threaded." For example, in a newsgroup for beer (alt.beer), one member might ask about good beer pubs in England and another will start discussing how to keep a beer fresh. More than one threaded discussion can occur at the same time with different members posting their opinions and reactions to either one or more threads.
Domain names have the format: hostname.subdomain.top-level-domain. My school's domain name, for example, is ocean.otr.usm.edu. This naming structure will give you clues about the address. Ocean is the name of the host computer, otr stands for "Office of Technology Resources" which manages the system, usm is the abbreviation for University of Southern Mississippi, the sub-domain, and edu signifies that this is an educational institution. The gov for the Library of Congress indicates it is a government institution.
Here are the existing top-level domains in the Internet:
Spam is unsolited junk e-mail sent to large numbers of e-mail addresses. It is used to promote some product or service and many spam e-mails are pornographic in nature.
Unfortunately there are not very many good ways of preventing spam other than keeping your e-mail address secret. It should be kept at a level of security somewhere between your phone number and your social security number. You should be careful about who you give your email address to. Many companies will sell your email address to spam lists, thus making it available to spammers.
I currently use three email accounts as follows.
I expect to change the third account pretty often, but hopefully the first two will last several years without much spam. The third account may be through a free internet email account service such as hotmail or yahoo.
Besides keeping your e-mail address secret, the next best spam relief are programs that help you manage spam. Spam can be filtered at the mail server with some programs or they can be a program that plugs into your e-mail client program such as Outlook or Outlook Express. Basically these types of programs filter spam based on several characteristics such as:
Unfortunately none of these scanning methods are 100% accurate although some claim to achieve success rates into the upper 90 percentile. What most of these programs do is to create folders for "friendly" mail or "unfriendly" mail. The friendly mail is put into one folder, unfriendly mail is put into a second folder and there may be a third folder for unknown mail. Unfriendly mail is automatically deleted after some period of time. The capabilities and handling of the mail will vary from program to program. Some that I have considered using include:
There are various opinions about what works when fighting spam. For more information and articles about how to fight spam you can find links to articles at Computer Technical Tutorials Spam .
If you are a webmaster, spammers will send spam to your domain by sending it to general possible accounts such as administration@yourdomain.com. One way to prevent this is to configure your account with your hosting provider not to respond to undeliverable emails and just automatically delete them. This is called a "::blackhole" setting. The only problem with this is that spammers will still use your bandwidth that you pay for to send you their junk, even though your server deletes them. As spam gets more excessive, it may increase bandwidth costs for webmasters thus discouraging some sites from operating.
When you connect to the internet, you are paying for a specific service for your use. This service costs a specific amount of money and provides a certan connection speed to the internet. This connection speed indicates your bandwidth. The greater the connection speed, the higher the bandwidth. The higher speed connections cost more money. At this poiint you have paid for the privilege of surfing the internet with your web browser, sending and receiving e-mail, and other activities. The speed at which you can do this is limited by your bandwidth and how fast you can click pages or send or receive e-mail. Consider the Following diagram:
Each person has a connection to the internet. If the person on the right chooses to use their connection to send e-mail or junk e-mail (spam), that is their choice. They are paying for their connection and they are willing to use it in that manner.
If the person on the left does not want to receive spam, but wants to read personal e-mail and surf the internet, they are willing to receive only personal e-mail. If someone is sending them a lot of spam, they will need to wait for the junk e-mail to be delivered before they can read much of their personal e-mail. They are an unwilling participant regarding the unsolicited e-mail they are receiving. Not only is their connection being used by someone else, but it will take them additional time to sort the mix of e-mail out to get to the mail they want to read. If the receiver had willingly stated that they were interested in receiving the advertisements, it would be another matter.
Of course the sender of the spam is not using all the spam receiver's internet connection, but the spam receiver does not get the opportunity to use their connection in the way they fully intended even though they were the one paying for it. This is the same as stealing even though the effective amount may be small. Imagine, how rich you could be if you could only steal a fraction of a cent per day or week from everyone who uses the internet. That's why spam should be illegal.
Someone may argue that spam is the same as junk mail sent through the postal service so why would it be stealing. This is not true since the sender of mail through the postal service pays for the cost of both pickup and delivery. On the internet, the sender pays for the cost of pickup and the receiver pays for the cost of delivery.
Unfortunately a permanent and good solution will take years to implement. A new mail protocol (method of sending e-mail) must be developed by the internet community and then e-mail servers must be modified to handle that protocol. The changing of the e-mail servers will take the most time.
I believe all e-mail should be digitally signed by the sender in order to be delivered. This way the sender cannot be faked and everyone must take responsibility for their own e-mails. However to get this to work right someone must find a way to keep viruses from being able to digitally sign your e-mails for you automatically. A bug in your e-mail client may allow a virus to digitally sign your e-mails causing this type of solution to be ineffective, however, in this case, there would be no doubt as to who has the virus.
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