Table of Contents

• Introduction


• Turning the Machine On


• The Operating System Takes Charge


• Windows


• Linux

Introduction
Have you ever asked yourself how many steps your computer performs from the moment you press the power switch to turn it on till the moment your favorite desktop wallpaper shines in its full glory in front of you? Well, there are many steps that the computer performs in order for you to be able to enjoy your powerful hardware and your slick software. When a step or two fails to execute and you can’t access the contents of your computer, you become more and more interested to know what exactly happens when you boot your computer and what could have potentially gone wrong to turn your ultra high-tech computer into a useless piece of metal and plastic.

Besides being interested to know what exactly happens when you boot your computer, being familiar with the basic steps that are executed during system boot can help you troubleshoot problems on your own, rather than depending on Technical Support for minor issues, like an unplugged power supply cable, for example.

If you are in Technical Support, then certainly it is a must to know the boot sequence of the type of machines you are supporting. Truth be told, if you are in Technical Support, you definitely need to know more about booting than what is presented in this article but I believe that even experienced Technical Support maniacs can learn something new from this article.

Although there are slight differences between the way different systems boot, generally the process can be divided into two areas — booting the hardware and starting the operating system. Basically, all PCs follow the same routine and if there are differences (mainly in the BIOS-related steps), you may want to check your vendors documentation before you take any steps to troubleshoot it further. Differences in the way the operating system boots are also possible and I have mentioned them occasionally. Also, though it is hardly possible to make an exhaustive list of all possible problems and their solutions for each of the stages, I have tried to suggest some of the reasons things go wrong and ways to fix the problem.

Turning the Machine On
The following is a detailed step-by-step break down of the hardware side of the boot sequence.

1. Switching on the power. When the power supply is switched on, its first task is to perform a self-test to ensure that power is stable — all voltages and current levels are normal. The self-test takes less than a half second and if you didn’t know about it, you would certainly never notice it, unless the computer freezes at this point. If the power supply does not pass the power self-test, this means that either the power supply unit is faulty, or that the voltage and current levels are not normal. So, when you turn on your computer and it just does not make any noise at all, one possible reason is a problem with the power supply. However, this does not necessarily mean that the power supply is dead — a more common reason can be an unplugged power supply cable.
   
   


2. Here comes the CPU. Before the CPU receives the signal and the power is stable, the processor receives continuous reset signals and just waits. After the power supply has made the power self-test, it sends a signal to the processor that the power is OK. The CPU starts operations and the first thing it does is to look in the BIOS ROM for the start of the BIOS boot program. Remember, the BIOS is the Basic Input/Output System that prepares the machine to run other software. It is commonly stored on ROM (Read Only Memory), or recently, flash memory that can be updated. Generally, the start of the BIOS boot program resides right at the end of system memory and usually it is only 16 bytes from the top of ROM memory. Of course, 16 bytes is quite insufficient for the program itself to reside, and there is absolutely enough for a JMP (jump) instruction, which tells the processor the actual address of the ROM BIOS code.
   
   


3. The BIOS POST is next. One of the first operations performed by the BIOS is the power-on self test (POST). The purpose of the POST is to determine if there are any fatal errors that prevent the proper booting or operation of the computer. Since at this time the video adapter is not started yet, all alarms about fatal errors are communicated in beeps. These beeps vary from manufacturer to manufacturer and their meanings can be found in the vendor’s documentation. If you hear your computer scream, try to distinguish the signals, look up their meaning in the docs and see if you can troubleshoot it on your own.
   
   


4. Looking for the video adapter. If the power-on self test is passed without errors up to here, it continues by looking for adapters that also need to load their ROM BIOS program in order to be initialized. After the video adapter has been initialized, you will see on screen all other messages about failed hardware.
   
   


5. POST continued. Besides checking the central hardware and the video adapter, the POST reads the BIOS identification and displays the data on screen. Another portion of the POST is the memory test, which is skipped if it is a warm-startup (warm startup is when you restart the computer, while cold startup is when you have to switch it on). The output of the memory test is displayed on screen — i.e. how much installed memory you have. If you see that the installed memory is less than what you physically have inside the computer box, this could mean that some of your memory might have stopped functioning (i.e. you have 2 blocks of 512MB each, which is 1GB in total but the memory test displays that you have only 512MB, which means that one of the two blocks is not working).  Depending on how many blocks of RAM you have, you might be able or you might be not able to continue booting. If you have 2 or more blocks of memory and at least one of them is working, you will be able to go further, though your computer will be slower because of the reduced memory. This memory scenario is an example of a non-critical error. The other less dire reason for missing memory is with a system uses an onboard video card; it often “borrows” RAM from primary memory to use as video RAM.

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Table of Contents:

• What are Processes?


• Windows Processes


• Killing the Bad Guys

What are Processes?
Process is one of the core terms needed to understand operating systems. The simplest but most precise explanation is that a process is a program in execution, a running instance of a program. In the study of operating systems there are several states for a process, such as running, blocked, or terminated, but this is too much detail for an average user who is just eager to monitor what is going on with his or her computer. (For those, who are interested in more detail, Operating Systems: Design and Implementation and Modern Operating Systems by Andrew Tanenbaum are excellent sources of in-depth information about processes and operating systems as a whole.)

Modern operating systems can handle many processes simultaneously, but it is important to know that at any given point the CPU is only running one process. The other processes are waiting for their turn to come. This is why you see a long list of the processes in the Task Manager. New multi-core processors allow more processes to run simultaneously but still this does not change the fact that while there are one (or many) processes that are running, a dozen others are waiting to be executed by the processor.

Many operating systems allow processes to be divided further - into threads. For example, if Program A is running as a Process A, Process A can have the following threads — A1, A2, and A3, all of which execute subtasks that are related to the execution of Program A. Threads are dependent on the process that started them and when the process terminates, they terminate as well. Process management is one of the basic activities of operating systems. When a process consumes too much CPU power, this slows down the whole system, so in order to free some resources, one or more processes can be terminated.

When processes are forcibly terminated, this often results in loss of data. However, given the choice between a hung system and a killed process, loss of data might be acceptable. There are processes that can not be terminated because their execution is vital for the functioning of the whole system. Also, killing processes arbitrarily is a bad idea (even if the operating system allows you to kill a process of your choice). The right approach to killing processes is to first identify which program started the process, then identify what resources it is using and finally to proceed with termination. Killing the bad guys, i.e. problematic processes, is described in the last section of this article.

Windows Processes
Now that we have had a brief explanation of what processes are, let’s see how they relate to Windows. Windows, as most of the modern operating systems, supports multitasking and multithreading. So, when you press CTRL+ALT+DEL to bring up the Task Manager, you will see something like this:

You see an Image Name column, where all processes for the currently logged in user are listed. If the Show Processes From All Users checkbox were checked, this list would have listed processes from all users. The name of the user who owns the process and data like the CPU and Memory usage of the particular process are listed next. Some of the process names are self-explanatory (firefox.exe) but others are a bit cryptic. Don’t worry that you can’t guess what a particular Image Name stands for–there are good online references, such as http://www.processlibrary.com or http://www.what-process.com/lists.aspx, where you can check what program a particular process represents.

However, it does not hurt to know the names of a couple of the essential Windows processes. There might be differences in the list of essential processes between the various versions of Windows but the major ones are as follows:

• System Idle Process


• explorer.exe


• winlogon.exe


• svchost.exe


• lsass.exe


• services.exe


• spoolsv.exe


• smss.exe


• csrss.exe


• taskmgr.exe

Usually several instances of Svchost.exe are running. This is usually normal because not all of them will be owned by the same user. What is not normal is that the same process — svchost.exe — has been registered both as a legitimate Windows process and as a trojan and backdoor. But more on this later. Svchost is a system process, which handles processes executed from DLLs. This is one of the most important processes in Windows and if you terminate it, your computer will become unstable. I am not going to explain all the processes here, so if you are interested in learning more about them, go to the above links, the lists there are very thorough.

I have used words like important and essential to describe the processes, but not all processes are equal. You can make one process more important than another through prioritization. By default all processes have a Normal priority. If you are running a very special program that requires more processing power, or it is important for the program to be processed as soon as possible, you can change its priority from Normal to Realtime, High, or Above Normal. Alternatively, if you would like a given process to have a lower than normal priority, select Below Normal or Low. Set priorities by right-clicking the process in the Image Name column and from the context menu selecting Set Priority. From the list of priorities, choose the desired one. You can change the priority for most of the processes, but not all. (System Idle Process is one of the few exceptions because it is a vital process that users should not be allowed to modify).

If you want more in-depth data about a particular process, for instance to see the whole process tree, the threads in the process, its network connectivity, or handles and DLLs, Windows Task Manager will not be useful. Instead, you can download a free program - Process Explorer by Mark Russinovich and see all this and a lot more information about the processes on your computer.

Killing the Bad Guys
When you right-click a process in the list of processes, you will see the End Process and End Process Tree commands. Choosing the first one terminates the process and the second – the process itself, along with all of its related processes. You will see a warning that terminating a process that way might cause system instability, but if you are killing a program that is not responding anyway, you might actually gain some system stability (or at least processor time). Killing a process through the Windows Task Manager is worth it only if the program has hung and you need to free resources.
Browsing through the processes in Windows Task Manager might also give you a clue if you have viruses, spyware, adware and other types of malware on your computer. If you notice a strange process in the list of processes, check to see which program it belongs to and if it is malware, take the appropriate measures (i.e. launch your antivirus or spyware programs).

Keep in mind that the fact that you don’t see any suspicious processes in the list of processes does not mean that your computer is clean. Most of the advanced malicious programs are written in a way that allows them to remain hidden and they will hardly show themselves in the processes list. Often, malicious code is hidden behind perfectly legitimate processes or uses the same name (the example with svchost.exe) as a Windows service or a popular program. It is therefore unlikely that you will notice it in the processes list of Windows Task Manager. But even if the malicious program shows in the list, stopping the process will not remove it from your computer. You need to take additional measures to clean it completely. Still, occasionally having a look at what processes are running at your computer is a good habit to have.

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Introduction
In the modern world, gaming enthusiasts of all ages spend thousands upon thousands of dollars on a new computer build with the latest high-tech components. They look for high-end processors, lots of memory, and very advanced graphics cards. And for those, it is no longer “acceptable” to spend less than x amount of dollars on a graphics card, simply because it is not sufficient. To keep this frenzy in perspective, an overwhelming majority of computer users have integrated graphics or low-end graphics card in their systems. This is not to say that the graphics card was neglected, but in reality, there is nothing to gain from a better graphics card. The latest and the greatest graphics card mean nothing to them.

Since the release of PCI-Express, the two graphics giants, nVidia and ATI, have picked up their pace of releasing new graphics solutions for all users. Specifically, the innovations of key technologies were not reserved for simply the high-end graphics users. nVidia and ATI started catering more and more to low-end consumers. For most of the graphics card industry’s short life, manufacturers have deemed making a card is too expensive for those who do not have deep pockets. Because of problems associated with manufacturing costs, manufacturers often crippled low-end graphics card chips. Some of the steps manufacturers took to make a budget card include:

• Underperforming GPU Core


• Less Rendering Pixel Pipelines/Processors


• Slower core and memory clockspeeds


• Limited local graphics memory

nVidia’s December 2004 release of their TurboCache Technology altered the scene. Making use of the latest release of PCI-Express, nVidia’s TurboCache, along with ATI’s incarnation of the technology called HyperMemory, crafted an efficient method of borrowing system memory for graphical use. By doing so, these cards no longer required a large amount of memory on the card itself. Does this concept sound familiar? Most of you were probably thinking “Integrated Graphics” or “Onboard graphics”. As a matter of fact, there are many similarities between integrated graphics and these technologies. In order to look into TurboCache and HyperMemory really offer, it is important to understand how integrated graphics works.

Before we delve into these technologies, I want to make a few terms clear as I will often refer to them throughout the article.

• Local Graphics Memory: Also the same as Video RAM (VRAM) or onboard RAM. Local Graphics Memory (LGM) refers to the supply of memory specifically reserved for graphical instructions. LGM is located on the graphics card itself. Currently, LGM comes in the form of Graphics DDR RAM (DDR, DDR2, DDR3).


• System Resources: Refers to the memory and processor cycles that are used by the entire system.


• Graphics Processing Unit: Interchangeable with Visual Processing Unit (VPU), the Graphics Processing Unit (GPU) refers to the device that physically renders graphical instructions.


• Cache: A very broad term, used to refer to a “quick” memory for the processing unit to pull data from.

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In the olden days of computing, everyone got a desktop computer.  Laptops became available in the mid to late 1980s, but they were clunky, expensive, and underpowered.  Some road warriors purchased a laptop, but they usually had a desktop as well because of the shortcomings of the laptops of the day.  However, over time laptops became sleeker, cheaper, and more powerful, and users started to get enthusiastic about them, sometimes using one as their primary computer.  At this point in history, laptops are only a bit more expensive than comparable desktops at the low end, and at the high end are essentially just as powerful.  Throughout the range of prices, there are laptops too big to fit in most cases as well as laptops that only weigh a couple of pounds and are very small.

So which laptop do you buy?  Unfortunately, it’s not as simple as going down to CompUSA and getting the cheapest one there, or the one that looks the coolest.  You have to do a fair amount of research first, and you should also figure out what you need the laptop to do and what your priorities are.  Important considerations also include what deals you can get to bring the price of more expensive laptops down, the reliability of manufacturers and specific models, and what specific features you need.

This article will cover the major steps in finding a laptop, including determining your needs, understanding the technologies that are advertised with each laptop, figuring out the exact laptop that is right for you, and figuring out exact specifications and accessories where necessary.

Do you even need a laptop?

Before you start looking, you should consider whether you need a laptop in the first place.  Desktops still excel in the realms of durability, expandability and usability.  They have big screens, spacious cases that make it easy to add or upgrade components, and nice keyboards and mice. 

Additionally, if you spill some coffee on the keyboard of your brand-new laptop, it will probably be fried; on a desktop all you have to do is go out and buy a new keyboard for $15.  Hard drives on laptops are also more likely to fail, and laptops are much harder to repair if something major goes wrong.  They usually have to be sent to professional repair services, and the components are expensive – a couple hundred for a new LCD screen, for example, or as much as $800 for a new motherboard.  Cracked screens and broken power jacks and PCMCIA slots are common problems with laptops that are usually not covered under warranty.

With that said, laptops are supremely useful if you ever have to move your computer.  They’re ideal for college students who carry their computer back and forth to class and the library and on vacations, and they’re also great for businesspeople who want to take notes in meetings and work from home or on a business trip.  They’re even convenient for people who just want to be able to work on the couch once in a while.  And when you’re at home, they can be converted to a good imitation of a desktop system by attaching external monitors, keyboards, mice, and other peripherals.

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Many of us have older computers stilting around that we don’t know what to do with - or at least enough leftover components to assemble a “basic” computer. And yet such computers can be used for many interesting projects. Even an older computer can be used. Even with only DOS and BASIC on your computer, the possibilities can be almost endless. (BASIC comes with almost any version of DOS, or can be found on older PCs, or on many Windows CDs. Older versions of Visual Basic can be bought fairly cheaply, and free BASIC versions can be found/downloaded).

What can you do with that old computer? How about turning your computer into a low cost home/business alarm system? One that will issue a visual and audio alarm if anyone comes in your house or business and it will tell you how many times and even the date and time, that anyone has entered and left your house, or any particular room in a building.

You can do this even project if you have limited technical knowledge. All that is required is a PC, two keyboards, a few standard burglar (momentary contact) alarm switches, or homemade switches, and a few lines of BASIC.

The Keyboard - Connecting Your Computer to the Outside
Your keyboard is designed such that each key will send out its own particular [ASCII] code when pressed. And your computer is designed to interpret each key as a particular letter, number, or symbol.

It is easy enough to write a simple program in BASIC that will register which key on the keyboard has been pressed and even issue a sound when the key is pressed.

“So what good is that?” you ask. Actually, not much - until you “wire in” to your keyboard. When you connect your keyboard into external devices/switchers, you can turn your computer into a home or building monitoring system.

To Build Your Home Monitor
To start with, get an old or cheap keyboard (and you’ll need a second working one to program your computer). Take the keyboard you want to use for the project and try to remove a few keys - or just disassemble the keyboard. Usually you can just pull individual keys out, but you may have to break the keyboard open to access the internal electrical contacts.

Many keyboards can be taken apart by removing screws located at the bottom. With other keyboards you may have to use a screwdriver at the side seam to break it apart. You can also use a screwdriver to remove a few keys from the keyboard.

Once you have taken the keyboard apart, or just removed a few keys, look for the keyboard circuit board, and the electric contacts associated with each key. You should see a point where the key makes electrical contact (or shorts) across two contacts. There is where you want to wire into. To test, you can use a piece of wire to try shorting the suspected contacts and watch for a letter to appear on your computer screen.

Note: Many types of keyboard designs exist. On certain keyboards you may have to cut through the plastic that to get to the electrical contacts. On other keyboards you may have to wire into the circuit board itself. In other cases you might want to try another keyboard that is easier to hack. The keyboard is a low voltage device, however, you still could damage it by shorting the wrong contacts. Examine the way an individual key works and try to track down the exact two electrical contacts that the key connects.

For wiring, “clear” speaker wire works nicely, it is easy to handle and easy to hide. About the smallest gauge of speaker wire you can find will work. Place the burglar alarm switches at doors or windows, and wire them back to your keyboard. Remember that a keyboard works on a momentary contact basis. So, that is the type of burglar alarm switch you want, one that makes momentary contact - about a quarter of a second should do.

In most cases you can make your own switch. If you install a simple electrical contact on a door and on the doorframe that makes contact during the time when the door is opening or closing, that would work.

Getting and Learning BASIC
With all the alarm switches wired in, you can now use BASIC to program your computer to indicate when a switch is activated. Learning BASIC is easy. I prefer older versions because they have the commands you need without requiring you learn the Windows environment. However, even Visual Basic can be used in a simple format - without the need to create dialog boxes and such.

Older versions of BASIC such as GW BASIC, QUICK BASIC, and QBASIC, can be found on most DOS disks, or Windows OS disks. Look for “Old DOS” or “DOS” directory on Windows 9x installation medium. You can also download a number of free versions of BASIC off the internet. Just search for “BASIC language” or “QBASIC” and so on. QBASIC still has a good following. To learn QBASIC, or to get help writing a program, try these tutorials/forums:

http://pages.intnet.mu/jhbpage/Program/Qbasic/tutorial/index.htm - Pretty simple. A good starting place
http://www.qbasic.com/ - Old and new forums
http://qbasicnews.com/learn/tutorials.shtml  - General information, news, forums

For Visual Basic, try these:

www.devdos.com/vb/wanttobe.shtml - A good starting point
www.vbtutor.net/vbtutor.html

The Program
As mentioned earlier, you can program the computer to indicate which switch has been activated (i.e. which window was opened), what time it occurred, and sound an alarm. The BASIC program is quite simple. Say that the “D” key is tied to the switch at the front door. Here is the program you would write:

(Note: this is a generic-BASIC program for an example. Check the manual/tutorial for the type of BASIC you use.)

10 CLS  [Clears screen]

20 CLEAR  [This command clears previous values (such as C=3) from memory.

30 A$=INKEY$  [This makes the variable A$ equal to whatever key that is closed]

40 IF A$= “D” THEN PRINT “FRONT DOOR OPENED” THEN PRINT TIME$: THEN SOUND 200, 180   [This tells the computer that if the D key has made contact, print on the screen "FRONT DOOR OPENED" and print the time it was opened, and issue a warning sound of 200 Hz for about 1 minute]

100 GO TO 20 [Return to line 10 to keep scanning keyboard]

This program will print out to the screen each time the door is opened [and closed], and sounds the alarm, and indicate the time. All entries will be printed on the screen.

Take note that line 40 is just one command for one key. Many such lines can be written for each key that to which you have wired a switch.  You could also have the computer monitor how many times the door has been opened, to indicate how many people came in or out of your house or building by adding to line 40: “THEN A=A+1″  This will cause A to increment each time line 40 is activated.

Going Further
Keep in mind that all you need is for electrical contact to be made, and relayed back to the keyboard. With a little imagination, you can make more than door and window switches.

How about a flood alarm? You can use a small float in a container, with wired contacts made such that if water lifts the float, electrical contact is made. With your imagination the uses of such a monitoring system should be almost endless.

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Introduction
In the summer of 2004, nVidia released a new technology into the gaming market.  The nVidia Corporation is known primarily for developing and supplying GPUs (Graphics Processing Units), motherboard chipsets, and contributing to other forms of multimedia hardware.  The latest buzz about nVidia centers around developments made with GPU and chipset technology.  These technologies are used in joint operation to produce a gigantic leap forward in gaming hardware horsepower.  This technology is called the “Scalable Link Interface”.

Surprisingly, SLI technology is not a new concept.  The first line of SLI products were produced by a video card company named 3dfx.  SLI was first used in arcade game consoles and other professional markets.  3dfx then released a consumer version of SLI in 1998 with their Voodoo2 video card line, which was called “Scan Line Interleave” at the time.  nVidia then reintroduced the basic concept on the PCI Express bus, while ATi still continues to tweak their version of a linked video card system named “CrossFire”.  Many gamers who have always used ATi products are debating whether to bite the bullet and go for nVidia’s SLI, or play the waiting game and sit tight for the final release of ATi CrossFire.

nVidia’s new SLI (Scalable Link Interface) technology has brought a new incentive for gamers to invest in nVidia video card technology.  Broken down into its simplest concept, SLI allows systems to utilize the power of two identical video cards for a single output display.  Utilizing any more than two is merely theoretical (or hypothetical) at this point.  The purpose of SLI is to offer better performance per cost of a system as a whole.  Typically, a single, significantly more powerful video card rivals the cost of two less powerful cards.  Plus, these two cards can be purchased separately (one initially, and the second as a later upgrade), defraying the cost of an expensive gaming system.  This certainly helps builders on a lower budget and helps keep an older machine usable for a longer period of time.

With a traditional gaming computer, you would find a motherboard, a CPU, RAM, and a video card making up a system’s core components.  SLI technology makes it possible to install two video cards, and have them operate simultaneously for a boost in image rendering performance.

First, we will introduce you to what the original SLI technology was, how it was used, and a brief history leading up to the current form of SLI technology, including current and past market influences leading to its demise and rebirth.  This is followed by architecture comparisons between technologies, the performance benefits of current SLI technology, and the hardware requirements for building a computer that would support SLI. 

After taking a look at the hardware side of SLI, we will dive into the software side of SLI, which is where the real magic happens.  Discussed are SLI’s rendering and Antialiasing methods in detail, plus some comparisons between their respective settings, which are critical pieces of the SLI setup as a whole.

Wrapping up the contextual portion of the document, we end with a brief look at the innovation of gaming technology and with our analysis of the best situation where SLI can be utilized effectively, taking cost vs. performance into account.  Performance in this case would equate to how efficient the technology would maintain an acceptable output response.  In other words, it must maintain an acceptable frame rate and quality.

3dfx SLI
The first line of SLI products from 3dfx were used in arcade game consoles and other professional markets. The Voodoo 2 series was the first SLI line available for consumers. In order to make it work, two PCI Voodoo 2 cards were required be linked together on the PCI bus, and connected by a ribbon cable. Vaguely similar to the way a TVs produce frames, 3dfx’s SLI technology allowed each card to process alternating horizontal lines in a single frame in order to produce a single complete frame.

This process allowed users to increase texture filtering to make use of trilinear filtering, increase the screen resolution to a new maximum (at the time, it was an impressive 1024×768), and increase the number of polygons that could be drawn, thus doubling the rendering throughput.

A major draw toward SLI technology was that it ensured that a gaming rig would not undergo premature obsoleteness. Once a single Voodoo 2 card was unable to keep up with the gaming demands that a gamer was putting on it, all they had to do was throw in a second video card and they would be ready to fly once more. The ability to add a second video card was a huge advantage over other competitors at that time.

Unfortunately, 3dfx crashed and burned due to its lack of innovation in later product lines, and merely tried to milk old product designs for all they were worth. The company was later gobbled up by nVidia, and the SLI project was forgotten and shelved for two reasons. Advancements in leaps and bounds with more powerful video cards made SLI unnecessary, and video cards had progressed beyond the limited PCI bus and had started to take advantage of AGP. It was not possible to link AGP and PCI buses to utilize SLI, or to have more than one AGP slot on a motherboard, for that matter. Therefore, nVidia did not feel it was worth investing in SLI technology at the time. Clock speeds and driver optimizations became the main focus and driving force behind the development of video cards. On the software side of things, optimizing video card drivers became an important key for card development, and often breathed new life into older cards.

nVidia SLI
After ATi gained a secure lead in the video card market with their superior image quality and performance, while nVidia fell behind a bit (more recently with their FX series cards) and needed to take innovation in a new direction.  The 6xxx series emerged, on both AGP and PCI Express buses, which was shortly followed by the reintroduction of SLI technology, thanks to the development of the PCI Express standard by Intel, finalized in 2002.  A few months later, nVidia moved to PCI Express only, which can be clearly seen with their 7xxx series video cards.

nVidia’s SLI technology employs rendering methods that go beyond 3dfx’s interleaving method on the PCI serial bus.  SLI takes advantage of the increased bandwidth of two 16x PCI Express slots, thanks to the nature of the parallel bus architecture.  Parallel bus architecture allows more work to be done in within same amount of time than what the PCI bus could do with its older serial architecture.  Parallel bus architecture allows more data to be transferred within same amount of time because of multiple dedicated lines (a.k.a “lanes”) running back and forth between the slots and motherboard chipset.

However, there is one caveat.  The two PCI Express 16x slots are 16x in name only when used in a dual-card setup.  The secondary 16x PCI Express slot is a branch off of the primary 16x PCI Express slot, thus effectively sharing the bandwidth between the two slots.  When only the primary slot is in use, it receives the full bandwidth, while the secondary slot remains in a deactivated state.  When both slots are in use, each slot is throttled down and receives 8x, thanks to lane width negotiation.

SLI also takes advantage various features of nVidia hardware, such as the capabilities of the GPU (Graphics Processing Unit; the video card’s CPU), but as well as the motherboard chipset, which manages data transfers for the SLI-enabled PCI Express slots, among other tasks. Depending on how a SLI setup is configured, it’s possible to get nearly double the performance than that of a system with only a single video card.  Various Benchmarks have estimated this performance gain to be about 1.5 to 1.9 times (or, 77% to 90%) greater in a dual card SLI setup.  This is a generalized estimation from an array of benchmark reviews on SLI.  The actual performance gain is dependent on a number of factors that will vary from computer to computer: the hardware components used, the ForceWare driver version used, and the benchmark program used.

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We’ve all heard it: “Backup, backup, backup.” Do you know why you need to back up? Yes, being prepared for the unknown is important, but this is actually a known fact: MOST HARD DRIVES WILL BE DEAD WITHIN 3-5 YEARS, and many do fail within the first year. Read that again. Now think about your 3 year-old PC… that hard drive is a ticking time bomb of pain just waiting for the most inopportune time to die or even just corrupt the data that is on there (which is just as bad or even worse from a data standpoint).

But how many of us actually do back up our data and how often? From my personal experience, very, very few people have backups that were made within the past month or three, if anything at all. But still, everyone acknowledges that they need to backup.

So why don’t they? Well, first off, it costs money. You need something to back up onto. Secondly, it takes effort and often isn’t trivial to do. Third, it’s boring (Well, it is. Do you REALLY want to spend hours trying to figure out what needs to be backed up, doing test backups, testing those backups, and then regularly performing the backups for the rest of your life? Yeah, me neither).

So instead, we take the risk, hoping and praying that nothing happens until we buy that next computer and copy everything over, thus effectively making our old computer the “backup,” even though it isn’t really one because it’s now been handed down to some other use, and the data on there now will potentially be changed or even deleted. So when we have to go back to it a year from now because that shiny new computer’s hard drive died, we are only able to recover 1/4 of our data, and we spend days upon days recreating it, and some data will just be lost forever.

Perhaps spending the time right now really is worth it in the long run. In this guide, we’ll look at the currently available options.

Backup Principles

Types of backups
There are three types of backups. The first is a full backup. This is a complete copy of everything that is to be backed up. It will use up the same amount of space as the files on the disk, before accounting for compression. Full backups are nice because you can just find the tape/file you need and restore it with no mess.

The second type is an incremental backup. Incremental backups only store the changes or changed files since the last backup, whether it is a full backup or another incremental backup. They typically save quite a bit of space since you aren’t storing many copies of the exact same files, and they are much quicker to process during the backup. The downside is that you’ll need the last full backup plus every incremental backup you made since then in order to restore the files. So restoration is more painful, and if there is a damaged tape or other media somewhere in the middle, you could potentially lose most of your data from that point forward. Incremental backups do require special backup software to track what files have changed and upon restore, to re-join the data from all the different backup sources.

The third type of backup is a differential backup. It is a middle ground between full and incremental backups in that it stores all files that have changed since the last full backup, ignoring any previous differential or incremental backups. That makes restoration much quicker than with multiple incremental backups, but it can require quite a bit more space and take longer to perform the backup.

How often to backup
Backup frequencies depend primarily on how fast/much your data changes and how important it is to you. If you only add and change a few files per week, a monthly full backup would be fine. Also keep in mind that something is better than nothing. It’s better to have a better to have a week-old or day-old backup than a month-old backup, month-old backup than a year-old backup, and a year-old backup than nothing at all.

This is really the first thing to decide when planning a backup strategy. Businesses typically do weekly full backups on the weekends and nightly incremental backups Monday through Friday. The hardcore approach is to do a full weekly backup, duplicate it, store the copies each in separate locations (different cities/states is even better), and then do nightly incremental backups. That way, even should something catastrophic happen (such as the destruction of the building with one set of backups), the business is still never more than one week out of date.

Of course, those same businesses have an IT staff that are responsible for tasks like backup management. If you’re reading this, though, you’re probably not nearly so well equipped. Instead, you could do monthly/bi-weekly/weekly full backups, and that would probably be good enough. Depending on the backup method you choose, you could also do some incremental backups between the full backups.

Price per Gigabyte
Since money is always in the mix, this has to be factored in. How much does it cost to back up one GB of data? This can be especially important if you want to keep multiple backups (say, weekly backups for the past month or two). The price might actually be higher than the hard drive the data is stored on right now.

You’ll also need to factor in the price of the drive for something like a tape drive that is only used for backup.

Speed of backup
The speed of the backup is relevant because you often can’t use the computer during the backup process (so data doesn’t become inconsistent between the backup and hard drive storage). So unless you’re going to start the backup at the end of the day (and that is very common), you’ll want the fastest backup method possible. With some backup methods, you’ll have to swap tapes, CDs, or DVDs in the middle of the backup so you’ll have to physically be present to do the swap. There are ways of automating that, too, but that starts adding to the price.

Ease and speed of data recovery
This is often something that is glossed over when considering backup options. If the backup can’t be restored quickly and easily, even more valuable time and energy will lost. The faster the data is back, the faster everything can return to normal. The more complex the backup (greater number of incremental backups and tapes/CDs/DVDs), the more complicated and slower the recovery will be. Speed of media transfer also plays a role here as well. If you have everything backed up over the internet, it might take hours and hours to download the backup.

Of course, for individuals, the speed isn’t as important as the ease. If it’s hard, it will take more energy and focus to figure out what to do for a recovery. That’s one of the reasons it’s important to do a practice data recovery so you’re familiar with what to do when you need to recover.

Number of previous backups held
It is a good idea to hang onto old backups. The reason is that a newer backup might become corrupted, damaged, or destroyed, or the data you backed up might actually be wrong. If you only have one backup, you’re out of luck. You need to have an older backup to turn to for those situations.

Of course, holding more backups on hand adds to the price of backup. So you want to try to find the right balance.

Off-site vs. On-site
On-site backups are ones you keep on the same premises, and off-site backups are ones that are stored somewhere else. Keeping your backups in the same building doesn’t do any good if it is destroyed by fire, and keeping them in the same city doesn’t do any good if that city is wiped out by a massive flood or other catastrophe. Of course, dealing with off-site backups are annoying because you have to get the data from here to there somehow, and then you need to be able to get it back quickly if the need arises, especially if off-site backups are the only option you are using.

Most individuals can get away with on-site only backups, but it’s still a good idea to keep all your important data at a friend or family member’s house that you really trust and update it every year or so… or whatever frequency you feel comfortable with. That way a fire to your house won’t destroy absolutely everything.

Backup Durability
How relevant durability is to you depends on your backup approach. If you do weekly full backups and keep one old backup, then you’ll be rotating through 2 sets of backup media, and it will never be more than 2 weeks since your media was last used. Usually with this scenario, the durability of the backup media (which is always measured in years) won’t really be a factor because it’s much more likely that the media will fail while you are creating the backup than during the one week where you really need to restore data from that tape.

However, if you only backup every year or so (e.g. to do the important data off-site backup), then you need to be aware of the media’s durability. If you actually wish to keep the media as an archive, then the durability becomes vitally important. You’ll still need to move the data onto new media every so often or you risk having losing the archive to media failure.

Another factor for durability is storage conditions. While CDs and DVDs often are said to have 20-100 year lifespans, a burned CD can be killed in a matter of hours by exposing it to direct sunlight. Magnetic tape is usually expected to last for 20-50 years, but data can be corrupted by a short exposure to a strong magnet. So you’ll also need to be aware of the media’s weaknesses and account for that as well. Most media prefers a cool, dark place with mild levels of humidity for maximum media lifespan.

Post from: PCMech. Helping Normal People Get Their Geek On And Live The Digital Lifestyle.

Introduction
Most of us cannot afford fancy 7.1 surround sound systems or feel that we do not utilize the computer’s audio functions enough to reap the benefit of one. However, most of us have stereos. That and a few cables is all you need to enjoy a nice audio system without damaging your bank account. In this article, I will show you an easy way to use your stereo as computer speakers for a nice sound system at a very low cost.

What you need
There are only a few things you need to create your new sound setup.

• Of course, a stereo. This stereo must have an auxiliary (aux.) port. Aux. ports are usually the two red and white ports located on the back of the stereo or receiver.


• A computer, duh! The computer must have at least a front audio output either on onboard sound or a sound card.


• Cables and adapters. This is where you may have to make a purchase. Both of these items can be found at a Radio Shack or other electronics store.

The item you need is a stereo patch cable:

Found Here. Get whatever length you need.

The second item is a stereo adapter:

Found Here. By no means do you have to get the gold-plated one, but sound quality might be improved a minor amount.

These three things are all you need to create you new audio system.

Connecting the Stereo to the Computer

1. Patch cable to stereo.
   Take one end of the patch cable (does not matter which) and attach it to the aux. port of the stereo. Red (right audio) to red. White (left audio) to white. Make sure they are securely connected.


2. Patch cable to adapter.
   Take the other end of the patch cable and attach it to the adapter. Again, red to red, white to white. Make sure they are securely connected.


3. Adapter to computer.
   Now take the 1/8″ plug of the adapter and plug it into the audio port on your computer. Either use the front audio port (usually the green one) or the one of your choice (see the Additional ideas for more info). Make sure the plug is all the way into the port, as any looseness may cause poor audio quality.
   

Using the New Sound Setup
Now comes the fun part. Using the new system. First, turn your stereo on and set it to the aux. setting. Some stereos have a switch, some have a button, each stereo is different. If you are unsure how to do this, consult your stereo manual. Then, open you favorite media player on your computer. Whether it is Windows Media Player, Winamp, or RealPlayer, it doesn’t matter. Finally select you favorite song and hit play. You should now be hearing music through your stereo. If not look at the Troubleshooting section.

To get back to hearing music from your stereo, stop the music on your computer and switch the stereo back to the CD, tape, or radio setting. Some stereos have the CD and Aux. settings combined into one, so that is why you must stop the music first.

Troubleshooting
If you do not hear music or the music is not playing through all the speakers, try the next few steps.

• Check all your connections. It is very common for a cable to come loose. This is the first thing to check when sound is not working properly.


• Check the audio levels on the computer and stereo. I know I have often had the computer output set to “Mute” or turned down very low. Also check the stereo volume level. Make sure “Mute” is off. Sometimes if you have the volume at a good level for CD playing, it will be too quiet for sound coming from the computer. You may have to adjust accordingly.


• Make sure all your audio drivers are installed on your computer. This is not as common as a problem, but can still happen.

Caution
Be sure not to set your stereo speakers too close to your monitor. Since stereo speakers are unshielded, they can affect CRT monitors in a bad way.

Additional Ideas
These are some fun things you can do with your new setup.

If you have a 5.1 or greater sound card and your old computer speakers, you can use them in your new setup. Plug the speakers into the front audio port (since they will most likely be in front of you on your desk). Then plug the adapter from your stereo into your back audio port (usually black). This can be a cool way to get surround sound.

You can use your computer as an additional CD player. Instead of switching back to your stereo to play CD’s you can place an audio CD in your computer’s disk drive and play the CD from there, which will still go through the stereo.

Conclusion
So now that you have saved a few bucks on a new audio system, you can enjoy computer audio with a fatter wallet. This new system can greatly enhance your gaming experience or just make computer audio more enjoyable.

Post from: PCMech. Helping Normal People Get Their Geek On And Live The Digital Lifestyle.

Even after a decade of promises, we still aren’t living in the paperless world. You’ll still need to have a printer. Older printers may have issues with the newest OSes, and many computers today are not sold with the parallel ports that older printers require. Newer printers are usually faster and have better print quality, and they can integrate directly with digital cameras. Multifunction printers integrate scanners for scanning, copying, and faxing. Those are all reasons you might need to buy a printer.

The basics of buying a printer are to determine your needs and budget, research the options, and then determine the best deal for you.

Determine needs and priorities

The first step to buying a printer is to determine your budget. Once you’ve done that, you can consider the printer’s speed, print quality, features, and consumables cost.

Budget

Your budget is the primary limiter of your options. The least expensive printers are $30 or even free after rebate, and high quality color lasers cost up to $1000. Cheaper printers tend to have poor build quality, slower and poorer drivers and OS compatibility, and higher consumables cost. For a good inkjet printer, I typically recommend preparing for a $150-200 budget. I tend to be leery of <$80 and pretty much all Lexmark printers. They have had terrible drivers and very high consumable costs.

Consumables Cost

Ink cost is closely related to the budget. Some printers will have you shelling out $40 for ink regularly while others are only $5-10 for a single-color ink cartridge. Many printer manufacturers are treating ink like razor blazes — give away the printer/razor and make money on the ink/blades. For that reason, consumable cost analysis is very important. However, the value of the consumables cost is only as important as the amount that you print. If you don’t print a lot, it may not matter.

In general, it’s better to prefer color printers with seperated single-color cartridges rather than a single color cartridge. The reason is that most people print predominantly one or two colors, and you’ll be throwing out perfectly good ink of one little-used color in order to replenish the much-used color ink that has run out.

Speed

Your requirement for printer speed is a function of how patient you are and how much you print. If you regularly print 50 color pages, getting a printer that can print 7 pages per minute (ppm) is easily worth the cost difference from one that can only print 2 ppm. The difference is a 7 minute print job instead of a 25 minute print job. Printers that are shared amongst multiple people usually need to be faster than the average printer. Manufacturers vary on whether they report speed in “normal mode” or “draft mode” and the quality/speed can be dramatically different between the two modes. It’s best to look for reviews that consider the quality differences and settings along with the printer speed at those settings.

One of the hidden factors of printer speed is the amount of time from when you press “Print” to when the printer actually spits out its first page. Many printers offload the print job computation to the printer driver, which will calculate the entire print job before beginning the print. This can mean a 20-60 second wait where the printer is sitting idle waiting on the computer to finish computing the print job and actually beginning to print. If you are printing a “rush” printout, that idle time can be particularly distressing because other printers would actually begin printing immediately and finish more quickly. That’s some food for thought.

Print Quality

Print quality is generally a combination of crispness and color accuracy and vibrancy. This is where review roundups can really help since it will allow you to compare how a single image is printed by several printers in order to get a feel for how the printers you are considering will fair. Quality can be affected by the type of paper used, and you’ll want to take account of the printer’s quality with and without special glossy printer paper.

Resolution is the spec manufacturers fall all over themselves to quote to prove their awesome print quality, but don’t fall for it. Read some comparative reviews to get a feel for the real world print quality, which might be dramatically different from what the specs indicate.

Features

Printer features can vary widely. Some printers are designed to be multi-function devices that scan, print, copy, and fax while other printers specialize printing photos and yet other printers are designed to be as small and light as possible for travel purposes. Some printers can connect to digital cameras or flash memory cards and offer the ability to print photos directly without the use of a computer. Other possible features are banner printing, large paper sizes (11″x17″ and larger) support, high quantity paper bins, and network/WiFi/infrared connectivity.

One of the downsides to the multi-function device is that you’ll typically get a machine that does some things well and some poorly. You will need to be especially cautious of the scanner speed/quality as well as the print speed/quality and consumables cost. This adds an extra degree of complexity to the research and decision process.

Post from: PCMech. Helping Normal People Get Their Geek On And Live The Digital Lifestyle.