Hardware

Q 1. What is Virtual memory? How can you change the virtual memory settings?
Ans: Virtual memory. Windows operating systems use virtual memory to temporarily store data when it is running out of the physical memory (RAM) in the computer. This data is stored in a file on the hard disk(which is known as swap file or paging file). For most Windows installations, the OS automatically manages the size of the paging file. You can manually increase or decrease the size of this file or split the file across multiple hard disks depending on your requirements.

If you feel that the system performance is poor, you can increase the size of this file or divide the file into multiple disks. The following steps explain how you can change the virtual memory settings in Windows XP:
1. Click Start ->Control Panel ->System.
2. Click the Advanced tab.
3. Click the Settings button in the Performance area.
4. Click Advanced.
5. Click Change in the Virtual Memory area.
6. Enter the “Initial size” and “Maximum size” and click Set.
7. Close all windows.
Q 2. What is RAM?
Ans: Random access memory (RAM) is considered the primary or main memory of the computer, and it allows quick data storage and access. This memory is used as temporary storage by the system and by applications during normal operation of the computer.

Q 3. What is the difference between SDRAM and VRAM?
Ans: Computer memory is commonly referred to as RAM, or Random Access Memory. Both SDRAM and VRAM are types of RAM, but they are used for different purposes.SDRAM is the primary memory used by computers and is located in memory slots on the motherboard. It is used to load the operating system and running programs. Therefore, the more SDRAM your computer has, the more programs it can run at one time. Having an abundant amount of SDRAM may also allow your computer to run faster that a similar machine with less RAM. This is because more data can be loaded from the hard drive and stored in memory, which enables it to be accessed more quickly.VRAM is short for "Video RAM" and is used to store graphics data. VRAM is typically located on the computer's video card, though on computers with an integrated video chip (such as entry-level laptops), it may be located next to the video processor. Regardless of where the VRAM is located, its purpose is to load and store video data. The more VRAM a computer has, the more 2D and 3D images it can display at one time. Therefore, computers with lots of VRAM have large buffers for 3D graphics and can produce faster frame rates than machines with limited VRAM. This is helpful when playing 3D games and using 3D rendering applications.

Q 4. Why does my cable appear to be missing pins?
Ans: Many different types of cables use pin connectors. These pins carry different streams of data to connected peripherals and other devices. Most cables with pin connectors have a male end that has multiple rows of pins. These pins connect to a female connector, which has receptacles for the pins.

Sometimes you may notice that there are more receptacle holes than there are pins. This is normal, as many cables do not use all the possible pins. In fact, some of the pins included with the cable may not even be used. This is because many connection standards are designed with scalability in mind, meaning extra pins are included for future use. Sometimes these pins may never be used, while other times they provide useful functionality for new hardware designs.

VGA CablesA common example of a cable that appears to be missing a pin is a VGA cable. A standard VGA port has 15 pin receptacles, organized into 3 rows of 5 pins each. However, the male end of the VGA connection is missing a pin in the middle row. This is normal, since the pin is not needed for the connection. Therefore, if you notice your VGA cable is missing a pin, don't freak out. It's just part of the design.
Q 5. How do I check how much memory my computer has?
Ans: The amount of memory, or RAM, installed in your computer can significantly affect its performance. For example, having several programs open at the same time may cause your computer to slow down if all the memory is being used. Having too little memory may also prevent you from being able to open applications that require a lot of RAM. (This information is typically listed in the program's system requirements). Therefore, it is helpful to know how much memory is installed in your computer.In Windows, you can view the amount of memory installed in your computer by right-clicking "My Computer" and selecting "Properties..." A window will open with the amount of RAM displayed underneath the "Computer" section of the window. This window can also be viewed by opening the "System" Control Panel.If you want to see how much memory your Windows computer is using, you can open the Windows Task Manager by pressing Control-Alt-Delete or Control-Shift-Esc. You can also right-click the Taskbar and select "Task Manager." Once the Task Manager is open, click the "Performance" tab to view how much physical memory is installed in your computer and how much is available.

Q 6. Why won't my computer boot up after I installed new memory?
Ans: Installing memory, or RAM, is a great way to improve the performance of your computer. However, there are many types of RAM, and it is important to install the correct RAM when updating your computer's memory.
For example, not all 1GB RAM memory modules are the same. Some may run at 400MHz, while others may run at 667MHz. A 1GB SDRAM chip may have 168 pins, while a SO-DIMM may only have 144. These and other differences can cause RAM to not work with your machine.

If you install the incorrect RAM in your machine, one of two things will happen. 1) The computer will boot up but will not recognize the new memory, or 2) The computer will not boot up at all. If you remove the new RAM and the computer boots up fine, it is pretty clear that the RAM is causing the problem.
While RAM chips can be defective, memory problems are usually caused by installing the wrong type of RAM. You can verify the RAM type using your computer's user guide or by searching for your computer model on websites that sell memory.
When buying RAM, it is also a good idea to make sure it has a lifetime warranty. That way, if the RAM is bad or ever has problems, you can get it replaced free of charge.

Q 7. How can I tell if a memory module is ECC parity RAM or non-ECC non-parity RAM?
Ans: Parity memory modules have an extra chip on them to check for errors. Therefore, non-parity memory should have an even number of chips on the module and parity memory should have an odd number. Typically, there will be 8 chips on a non-ECC module and 9 chips on an ECC module.
However, some parity SIMMs can have 12, 18, 24 or 36 chips. Therefore, a sure-fire way to determine of a memory module is parity or non-parity is to divide the number of chips on the module by three. If the number is evenly divisible by 3, it is a parity, or ECC module. If the number of chips is not divisible by three, the module is non-parity, or non-ECC.

Q 8. Can I replace non-ECC memory with ECC memory?
Ans: ECC (Error Correcting Code) memory is parity memory and non-ECC memory is non-parity. Parity memory has an extra chip on the module that checks for errors in the transfer of information to and from the memory. So if a memory module has an odd number of chips, it is parity RAM.

Many motherboards support both ECC and non-ECC memory. Some sources say you can even mix the two types of RAM and the ECC RAM will work as non-ECC memory. However, most memory companies do not support mixing the two types, so try it at your own risk. Since most motherboards will accept ECC memory, it often depends on if your computer's BIOS supports it. You may have to check your computer's manual to find the answer.
If you have a choice, non-ECC memory is typically cheaper than ECC memory and works slightly faster. So when in doubt, use non-ECC memory.

Q 9. How do find out how much RAM my computer has and how much it is using?
Ans: Knowing how much RAM, or memory, your computer has is important because it determines what programs you can run on your machine. The more RAM you have, the more memory-intensive programs you can run. It also allows you to run more programs at one time. Having "excess" RAM is even beneficial, as it helps your computer avoid bottlenecks when processing large amounts of data.

If you are using Windows, you can find out how much RAM you have by right-clicking the My Computer icon and selecting "Properties..." This will open the System Properties window and you can view the amount of physical memory installed under the General tab. You can find out how much memory your computer is currently using by right-clicking anywhere in the open space of the Taskbar and selecting "Task Manager." Then click the Performance tab of the window that opens and you will be able to view your memory usage.

If you are using Mac OS X, you can see you much RAM is installed in your computer by choosing "About This Mac" from the Apple menu. This is located in the far upper left-hand corner of the screen. To find out how much memory is being used, open the Activity Monitor program, located in the Utilities folder (within the Applications folder). Then click the System Memory button near the bottom of the window to see how much memory your system is currently using.

Q10. What does scalable mean, in reference to a computer?
Ans: Scalable is synonymous with expandable. A computer with a scalable architecture is able to be upgraded easily and for a long time. When buying network equipment, it is especially important that it is scalable so that it can work with the newer systems that may be added on later. The less scalable your equipment is, the sooner you'll be forced to upgrade.

Q 11. What is the difference between the AMD Athlon and Intel Pentium processors?
Ans: Intel and AMD (Advanced Micro Devices) are the two major manufacturers of processors for PCs. Intel makes the Pentium and Celeron processors; AMD makes the K6 and Athlon processors.

So what's the difference? Well, historically, Pentium processors have had the best overall performance. However, the new AMD processors are faster than their Pentium counterparts in some tests. In general, you'll pay the most for an Intel processor, which means the AMD processors typically have a better price-performance ratio.

Q 12. Why do videos run slow on my computer?
Ans: First of all, make sure you have the latest driver software for your video card. To get the latest version, you can go to the video card company's web site and download the driver update for free. I would suggest defragmenting the hard drive, since excessive hard disk scanning can prevent smooth audio and video playback. If neither of these options do the trick, try upgrading to the latest version of the software you are using to play the movies. Finally, if that doesn't work, you might just not have enough hardware power to play the video smoothly. That means you need to actually go buy a new video card if you want smooth, high-quality video. Doh.

Q 13. Why won't my scanner work?
Ans: There are a couple of things that could be wrong with your scanner setup: 1. The drivers may have not been installed correctly (this is the most likely problem). Try reinstalling the software that came with the scanner. 2. The SCSI ID the scanner is using is already in use. Each SCSI device must have a unique ID or conflicts will happen. To change the ID, select a new number (most likely on the the back of the scanner). 3. The scanner or scanner software is incompatible with the computer. Check to see if the computer meets the scanner requirements. Also check for the latest version of drivers at the manufacturer's web site. 4. You don't have a good software program to control and import the scans. If the scanner didn't come with any software programs, the best program to use is Adobe Photoshop. If you just need a simple program that won't empty the bank, try Adobe Photoshop LE, Adobe PhotoDeluxe, or Jasc Paintshop Pro.

Q 14. What is the difference between AGP and PCI graphics cards?
Ans: AGP (Accelerated Graphics Port) cards serve the same purpose as PCI graphics cards. However, the AGP interface, which was created by our buddies at Intel, has become the more popular choice for PCs. Part of the reason for this is that AGP cards manage memory better than PCI cards. The AGP interface can actually use your computer's standard memory as well as the video memory to help boost video performance. So, if you have an AGP slot in your computer, I'd go with an AGP card. If you only have PCI slots, however, a PCI graphics card isn't going to be much different.

Q 15. Is it possible to increase the number of available PCI slots on my computer?
Ans: Unfortunately, you can't increase the number of PCI slots inside your computer. The only option you have, other than buying another computer, is to get a PCI tower, which has multiple PCI slots. The tower connects to any PCI slot on your computer's motherboard. (For example, it could turn one slot into six.) However, these are typically only used by people that do high-end video editing, and they are pretty expensive.

Q 16. Why is my mouse jumpy?
Ans: If the cursor on your screen isn't following the movement of your hand, there's a good chance you've got a dirty mouse. No matter how hard you try, it is basically impossible to keep your mouse pad dust and dirt free. And after hours and hours of rolling on a dirty surface, your mouse ball is bound to pick up some gunk. This grime gets twisted around the rollers inside your mouse and prevents them from rolling smoothly against the mouse ball. Since these rollers are what tell your computer what the mouse is doing, it's not good when they don't roll.
So if your cursor isn't moving how you want it to, before you decide to throw your mouse against the wall, check to see how dirty it is. To check the mouse, twist off the cover on the bottom that holds the ball in. Then take out the ball and examine the rollers. If you can see stuff on them, it's time to clean 'em. To clean the inside of your mouse, you can use a Q-tip or even your fingernails to get the dirt off the rollers. Make sure you clean all the way around them. Then blow inside the mouse to make sure everything gets out. Finally, wash off the mouse ball with soap and water and dry it. It is also a good idea to clean off your mouse pad. Once you've done all this, you can put the clean ball back in your clean mouse and experience smooth rolling freedom once again.Of course, if you have an optical mouse, this should never be a problem. =)
Q 17. What is the difference between burning and ripping?
Ans: "Ripping" refers to extracting audio files off a CD and copying them to your hard drive. After ripping the audio, you can then convert the files to the more compressed MP3 format if you want.
"Burning" refers to the process of writing data onto a CD. You can burn both audio and data CDs, as well as DVDs, provided your computer has a CD/DVD burner.
Q 18. What does it mean when a computer is "low on resources?"
Ans: The resources a computer has are mainly processing speed, hard disk storage, and memory. The phrase "low on resources" usually means the computer is running out of memory. The best way to prevent this error from coming up is to install more RAM on your machine. Upgrading your RAM is the best performance booster you can give your computer, and it usually doesn't cost a lot.

Q 19. Can I fax a document without a fax machine?
Ans: There are a number of fax programs available for faxing documents electronically using your computer's modem, or simply through the Internet. Some popular fax programs include FaxSTF (Mac) and Fax Wizard (Windows). These programs allow you to fax electronic documents such as Word documents or documents you scan into your computer. I would suggest visiting Download.com for a shareware fax program if you don't have one or visiting eFax.com for more information.

Q 20. What are the Alt (Option) and Control (Ctrl) keys for?
Ans: These keys on the keyboard are called "modifier keys." They are typically used in conjunction with another key on the keyboard to perform a specific function. For example, in Windows, Alt-F4 (press and hold Alt, then press F4) is often a shortcut to close the active window. Control-C is usually a shortcut to copy selected text or a selected object. Control-V is the shortcut for pasting the copied data.
On the Macintosh, the Command (or Apple) key typically has the same function as the Control key in Windows. The Control key on the Mac can be pressed while clicking the mouse button to perform a right-click. Many programs on both Macs and PCs use mutliple modifier keys for shortcuts for certain operations. For example, to save an image for the Web in Photoshop, you can press Ctrl-Alt-Shift-S in Windows or Command-Option-Shift-S on the Mac.
Q21. Will a USB 1.0 or 1.1 device work with my computer that only has USB 2.0 ports?
Ans: The device (digital camera, card reader, scanner, hard drive, cable modem, etc.) will work with the USB 2.0 ports even if the device only has a USB 1.0 or 1.1 connection. The physical connectors are exactly the same for USB 1.1 and USB 2.0. However, the device will only work at USB 1.1 speeds (12 Mbps) and not USB 2.0 speeds (480 Mbps).

Conversely, if your computer only has USB 1.0 or 1.1 ports and you would like to use a USB 2.0 device with it, the device will probably work. Again, you will only be able to transfer data at the slower USB 1.1 transfer rate. Most USB 2.0 devices are backwards compatible with USB 1.1, but for data-intensive devices (like a hard drive or iPod), the data transfer is so slow with USB 1.1, it may not even be worth using it.
Q 22. What is the difference between an AGP and a PCI graphics card?
Ans: The biggest difference between AGP and PCI graphics cards is that AGP cards can access the system memory to help with complex operations such as texture mapping. PCI cards can only access the memory available on the actual card. AGP doesn't share bandwidth with other devices, whereas PCI cards do. AGP also makes pipelined requests, which means it can execute multiple instructions at one time. PCI cards are not pipelined, which means each instruction has to finish before the next one is run.

So, with all these great advantages of AGP, you'd think it would be the clear winner in performance, right? Well, not quite. Tests of similar AGP and PCI graphics cards show they perform almost the same (typically measured in frames per second). The area where AGP really shines is in high-resolution tests, where the direct access to the system memory is most beneficial.
If you're installing an AGP or PCI card in your computer, the AGP slot is usually the shortest and should be brown. The PCI slots are slightly longer and are colored white. The actual size of the cards can vary as much as a few inches, though the pins on the bottom of the card should match the correct slot.
Q 23. What do I need in order to burn my own CDs?
Ans: To create or "burn" your own CDs, you need three things: 1) an operating system or program that supports CD burning, 2) a CD-burner, and 3) recordable CDs.

Of the three, it is most likely that you already have the first one. All recent versions of Microsoft Windows and Apple's Mac OS support CD burning. Programs like iTunes and Toast can be used if the operating system does not include CD burning functions.

Secondly, you need a CD burner. Technically, this is either a CD-R or CD-RW drive. A basic CD-ROM drive will not burn CDs. CD-R drives can record data on recordable CDs, while CD-RW drives can write and rewrite data onto rewritable CDs as well as record once on regular CD-R discs. CD burners can be either internal (inside the computer) or external devices. If you buy an internal drive, it may be wise to have an authorized technician install it.
Once you have installed the CD burner hardware, you need discs to use with the CD burner. As described earlier, CD-R discs can be recorded once while CD-RW discs can be erased and rewritten multiple times. CD-RW discs can only be used with CD-RW drives. Once you have some blank CD-Rs, just insert one of the discs into your CD burner and follow you operating system's instructions for creating either a data or audio CD.
Q 24. What is the difference between memory and hard disk space?
Ans: Memory and disk space are perhaps the most widely-confused terms in the computing world. To truly comprehend how your computer works, you must first understand what memory and disk space are.
The hard disk, sometimes called the "hard drive," which is actually the mechanism that holds the hard disk, is a spindle of magnetic discs that can hold several gigabytes of data. Therefore, disk space refers to how much space you have available on your hard disk for storing files. When you save a document or install a new program, it gets stored on your hard disk. The more files you download, install, or save on your hard disk, the more full it becomes.
Memory, on the other hand is not the same as disk space! Memory refers to the random access memory (RAM) inside your computer. These are small chips that hold several memory modules side by side. Your computer uses memory (RAM) to store actively running programs on the computer, including the operating system. For example, the operating system's interface and other processes get loaded into memory when the computer boots up. When you open a program like Microsoft Word, it gets loaded into the computer's memory as well. When you quit the program, the memory space is freed up for other programs.
RAM can be accessed several hundred times faster than a hard drive, which is why active programs must be loaded into the RAM from the hard drive. Because most data on the hard disk does not need to get loaded into the system memory at one time, computers typically have much more hard disk space than memory. For example, a computer may come with a 200 GB hard drive, and only 1 GB of RAM.
So if your computer tells you that you don't have enough space to install a program, you will need delete files from your hard disk that you don't need or buy an additional hard drive. If your computer says there is not enough memory to run a certain program, you will need to upgrade your memory by buying more RAM. Knowing the difference between these two types of hardware can save you precious time and money.
Q 25. What is the difference between physical memory and available memory?
Ans: Physical memory is how much RAM you have installed in your computer. For example, if you have two 512 MB memory chips in your machine, you have a total of 1 GB of physical memory. This memory is what your computer uses to load the operating system as well as individual programs and files.
Available memory refers to how much RAM is not already being used by the computer. Because loading the operating system takes up memory, your available memory drops right after your computer boots up. You can reduce how much memory the operating system uses by uninstalling system files or extensions that are often installed by utility programs.
Each time you open a program, it is loaded into your computer's memory, and therefore reduces your available memory. Large programs such as Adobe Photoshop and 3D action games take up more memory than simple programs like text editors or spreadsheet programs. If you need more available memory to open a large program, you should first quit other programs that are running.
The best way to increase available memory is to add more RAM, or physical memory, to your computer. Before doing this, make sure your computer has open memory slots. Some utility programs claim to "double your RAM," but they often slow down your computer signficantly in the process. Adding more physical memory to your computer gives your applications more breathing room and therefore should help your computer run faster.
Q 26. Can I use a generic v.92 modem from Wal-Mart in my Dell computer?
Ans: It may surprise you to learn that most companies don't make the modems that go into their computers. Instead, companies such as Dell use modems from other manufacturers who specialize in making modems. Therefore, a modem you buy from Wal-Mart should work just as well as one you buy from Dell.
However, you should check the system requirements of the modem you are interested in to make sure your computer supports it. It is most important to check the required operating system since the drivers need to be compatible with the OS. If the software drivers don't work with your operating system, your computer may not be able to recognize the modem.
Q27. How can I upgrade my computer to USB 2.0?
Ans: The answer to this question depends on if you have a desktop or a laptop computer.
If you have a desktop, you need at least one available PCI slot. This expansion slot is located on the back of your computer and and is usually covered by a metal plate that you must remove before installing a PCI card. You can install a USB 2.0 PCI card into this slot, which will give your computer USB 2.0 connectivity. Most USB 2.0 cards have several USB ports on them, so you can connect multiple USB devices to the card.
If you have a laptop, your computer will need to have a PCMCIA slot. (It is also called a PC card slot, which is much easier to say.) The slot is typically located on the side of the computer and is a little over five centimeters wide. It should be covered by a protective flap that will push in when you press on it. You can install a USB 2.0 PC card into this slot, which will give your computer one or more USB 2.0 connections.
As long as your operating system supports USB 2.0, you can install a USB 2.0 card whether or not your computer already has USB 1.1. Note that connecting a USB 2.0 hub or USB 2.0 device to a USB 1.1 port will cause the device to run at the slower USB 1.1 speed. Since USB 2.0 is 30-40 times faster than USB 1.1, it may be worth the upgrade.
Q 28. What are some examples of computer peripheral devices?
Ans: A computer peripheral, or peripheral device, is an external object that provides input and output for the computer. Some common input devices include:
keyboard
mouse
joystick
pen tablet
MIDI keyboard
scanner
digital camera
video camera
microphone
Some common output devices include:
monitor
projector
TV screen
printer
plotter
speakers
There are also devices that function as both input and output devices, such as:
external hard drives
media card readers
digital camcorders
digital mixers
MIDI equipment
While these are some of the more common peripherals, there are many other kinds as well. Just remember that any external device that provides input to the computer or receives output from the computer is considered a peripheral.

Q 29. How can I print to a printer connected to an Airport Base Station?
Ans: The Airport Extreme and Airport Express Base Stations both have a built-in USB port that allows you to connect a printer. Whatever printer you decide to connect to an Airport Base Station will be available to all computers connected to the Base Station.
In order to print to an Airport printer, you first need to make sure your computer is connected to the wireless router (the base station) either wirelessly, or directly with an Ethernet cable. If you are using a Mac, you can simply select the Base Station from the drop-down menu by clicking the Airport icon in the upper right-hand corner of the screen. Windows should allow you to choose the Base Station if you click the wireless network icon in the systray, located in the lower-right part of the screen.
The second thing you need to do is make sure the printer drivers for the printer are installed on the computer. Your computer will not recognize the wireless printer if you have not installed the correct drivers. You should be able to use the disc(s) that came with the printer or download the drivers from the manufacturer's website. After installing the drivers, you may need to restart your computer.
Once you've installed the printer drivers and established a network connection with the Airport Base Station, you should be able to print to the wireless printer. Just select "Print..." in whatever program you want to print from and then choose the printer from the list in the dialog box that pops up. The computer should recognize the printer as if it was connected directly to the machine. Once you click "Print," the file will get sent to the Base Station and the printer connected to it will print the document.

Q 30. What is the difference between Firewire 1394a and 1394b?
Ans: Firewire is a high-speed digital interface that comes in two varieties - 1394a (or just 1394) and 1394b. The 1394a standard (Firewire 400) supports data transfer rates up to 400 Mbps and uses a 6-pin connection. The 1394b standard (Firewire 800) can transfer data up to 800 Mbps and uses a 9-pin connection.
An 6-pin to 9-pin adapter can be used to plug a 1394a cable into a 1394b port, but the speed will be limited to 400 Mbps.
Q 31. What is the difference between the DVD-R and DVD+R formats?
Ans: DVD-R (pronounced "DVD dash R") and DVD+R (pronounced "DVD plus R") are nearly identical formats. The discs look the same and are both supported by most DVD-ROM drives and DVD burners. The only difference between the formats is the way they determine the location of the laser beam on the disc. DVD-R discs use tiny marks along the grooves in the discs, called land prepits, to determine the laser position. DVD+R discs do not have land prepits, but instead measure the "wobble frequency" as the laser moves toward the outside of the disc.
The DVD-R format was developed by Pioneer and was released in the second half of 1997. DVD+R was developed by Sony and Philips and was introduced in 2002. Companies that support DVD-R include Pioneer, Toshiba, Hitachi, and Panasonic, while companies that support DVD+R include Sony, Philips, Hewlett-Packard, Ricoh, and Yamaha.
However, most of these companies now develop hybrid DVD drives that support both DVD-R and DVD+R formats. They are known as DVD?R or DVD?RW drives. When looking for media for your DVD drive, make sure it ends in "-R" if you have a DVD-R drive or "+R" if you have a DVD+R drive. If you have a DVD?R drive, you can use either format. DVD-R is still more popular than DVD+R, but since they are both widely supported, it should not matter which format you choose.
Q 32. How can I tell if my CD/DVD drive burns CDs or DVDs?
Ans: If the drive only says "CD-ROM" or "DVD-ROM" then it probably does not burn CDs or DVDs. If it says CD-R, then it can burn recordable CDs and if it says CD-RW, it can write and rewrite to rewritable CDs.
If the drive says DVD-R or DVD+R, it can burn DVD-R or DVD+R discs. If it says DVD-RW or DVD+RW, then it can burn rewritable DVDs.
Drives that can burn CDs and read DVDs are often referred to as "Combo Drives" by many PC manufacturers. Apple Computer uses the term "SuperDrive" to refer to drives that can read and write to both CDs and DVDs.

Q 33. What does it mean to "power cycle" a device?
Ans: Power cycling an electronic device is a technical way of saying "resetting" it. When you power cycle a device, you turn it off and then turn it back on again. Pretty high-tech, huh? Usually, you should let the device sit for a couple seconds after turning it off to make sure the memory in the device is fully cleared before turning it back on.
Any electronic device can be power cycled, but the term is frequently used with cable modems, DSL modems, and routers. This is because small internal errors in these devices can prevent them from functioning correctly. Resetting them typically fixes the errors and allows them to work correctly again.
Q 34. What are primary and secondary storage devices?
Ans: A computer stores data using several different methods. Therefore, there are different levels of data storage, which may may be referred to as primary and secondary storage. While there is no official definition of these two terms, primary storage typically refers to random access memory (RAM), while secondary storage refers to the computer's internal hard drive.

RAM, commonly called "memory," is considered primary storage, since it stores data that is directly accessible by the computer's CPU. RAM is a high-speed storage medium that can be accessed with minimal delay. Because the RAM is connected directly to the CPU via the memory bus, the CPU can access data stored in RAM very quickly. For this reason, RAM is used to store data loaded by active programs and the operating system.
Hard drives are considered secondary storage since they are not connected directly to the CPU. Instead, hard drives send and receive data through an I/O bus, which may pass through a cache or other type of memory before getting to the CPU. Also, hard drives are not as fast a RAM, which means they cannot transfer data as quickly. However, unlike RAM, hard drives retain data when the computer is turned off. This is because hard drives store data magnetically, while RAM requires an electrical current.
While the computer's primary internal hard drive is the most common secondary storage device, other devices may be considered secondary storage devices as well. These include additional internal hard drives, external hard drives, and optical drives, which are used for CDs, DVDs, and other optical media.

Q35. What is SMP?
Ans: Symmetric Multiprocessing, a computer architecture that provides fast performance by making multiple CPUs available to complete individual processes simultaneously (multiprocessing). Unlike asymmetrical processing, any idle processor can be assigned any task, and additional CPUs can be added to improve performance and handle increased loads. A variety of specialized operating systems and hardware arrangements are available to support SMP. Specific applications can benefit from SMP if the code allows multithreading.

SMP uses a single operating system and shares common memory and disk input/output resources. Both UNIX and Windows NT support SMP.

Q36. Which Intel and AMD processors support SMP?
Ans: The most popular entry level SMP systems use the x86 instruction set architecture and are based on Intel's Xeon, Pentium D, Core Duo & Core 2 Duo based processors and AMD's athlon64 X2, Quad FX or Opteron 200 & 2000 Series.

Q37. How do LGA sockets differ from PGA and SEC?
Ans: PGA-Short for pin grid array, a type of chip package in which the connecting pins is located on the bottom in concentric squares. PGA chips are particularly good for chips that have many pins, such as modern microprocessors.
LGA - Lang Grid Array (CPU with contacts and the socket on the motherboard holds pins).

Q38. What is the difference between Pentium 4 and Pentium core 2 Duo? Explain the new technology.
Ans: Pentium 4 (with 1 single-core die) was superseded by the Pentium D (64bit processor, comprised with two single-core dies [NetBurst microarchitecture] in one package) and Pentium Extreme Edition brands of dual-core CPUs. The core-duo or dual core pentium had both cores placed on each dual-core die (Core architecture) with a reduced power consumption.

A dual-core device contains two independent microprocessors and a quad-core device contains four microprocessors. A multi-core microprocessor implements multiprocessing in a single physical package.

A dual-core processor is like a four-lane highway—handling up to twice as many cars as its two-lane predecessor without making each car drive twice as fast. Similarly, with an Intel dual-core processor-based PC, you can perform multiple tasks such as downloading music and gaming simultaneously.

If you are performance conscious, go for Core Duo. If you are budget conscious, then Pentium 4 or Pentium D is quite ok...just add mem stick and improve your video care using PCI vcards instead of AGP vcards...with the same bit, the latter runs slower.

Q39. How does IRQ priority works?
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Q40. What happens if you dissemble the battery located on the Mother-Board?
Ans:

Q41. How do L1, L2, and L3 work?
Ans: cache memory is a high speed memory kept in between processor and RAM to increase the data execution speed. It is kept near to the processor.
There are different levels of cache.
L1-cache is the fastest cache and it usually comes within the processor chip itself. The L1 cache typically ranges in size from 8KB to 64KB and uses the high-speed SRAM (static RAM) instead of the slower and cheaper DRAM (dynamic RAM) used for main memory.
The Intel Celeron processor uses two separate 16KB L1 caches, one for the instructions and one for the data.

L2 cache comes between L1 and RAM(processor-L1-L2-RAM) and is bigger than the primary cache (typically 64KB to 4MB).

L3 cache is not found nowadays as its function is replaced by L2 cache. L3 caches are found on the motherboard rather than the processor. It is kept between RAM and L2 cache.
So if your system has L1,L2 and L3 cache data fetching will be L1->L2->L3->RAMie. If data is not there in L1 it will check L2 then L3 then RAM...

Q42. What technology enables you to upgrade your computer’s BIOS by using simply a software?
Ans: Upgrading the BIOS (Basic Input Output System) of your computer's motherboard, also sometimes called 'flashing,' used to be a complex operation full of potential perils for your PC. The task involved downloading the correct BIOS file, the proper CMOS chip flashing software, rebooting the PC into DOS mode, applying the correct commands and then waiting in suspense until the update finished. All the while there was a lurking danger - if something went wrong, you would be left with an essentially unusable motherboard… Not an operation for the novice, and not one that even PC enthusiasts approached with enthusiasm.

Q43. How should we install RAM on a Dual-channel motherboard?
Ans: If your motherboard uses dual-channel architecture, you will need a pair of RAM modules. If you want a total of 1 GB, you then need 2 RAM modules of 512 MB. It is imperative to install computer memory modules from the same manufacturer with the same clock rating from the same standard.

Q44. What is the advantages of serial over parallel bus?
Ans:

Q45. Is USB using serial or parallel bus? What about firewire?
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Q46. What is UPS?
Ans: Short for uninterruptible power supply, a power supply that includes a battery to maintain power in the event of a power outage. Typically, a UPS keeps a computer running for several minutes after a power outage, enabling you to save data that is in RAM and shut down the computer gracefully. Many UPSs now offer a software component that enables you to automate backup and shut down procedures in case there's a power failure while you're away from the computer.

There are two basic types of UPS systems: standby power systems (SPSs) and on-line UPS systems. An SPS monitors the power line and switches to battery power as soon as it detects a problem. The switch to battery, however, can require several milliseconds, during which time the computer is not receiving any power. Standby Power Systems are sometimes called Line-interactive UPSes.

Q47. What is thw difference between standby and online UPS?
Ans:

Q48. What is SAS?
Ans: Short for Serial Attached SCSI, an evolution of parallel SCSI into a point-to-point serial peripheral interface in which controllers are linked directly to disk drives. SAS is a performance improvement over traditional SCSI because SAS enables multiple devices (up to 128) of different sizes and types to be connected simultaneously with thinner and longer cables; its full-duplex signal transmission supports 3.0Gb/s. In addition, SAS drives can be hot-plugged.

In topologies with more than two connected devices, SAS calls for the use of expander devices to allow for more than one host to connect to more than one peripheral.

SAS devices can communicate with both SATA and SCSI devices (the backplanes of SAS devices are identical to SATA devices). A key difference between SCSI and SAS devices is the addition in SAS devices of two data ports, each of which resides in a different SAS domain. This enables complete failover redundancy as if one path fails, there is still communication along a separate and independent path.

Q49. What are the three main reason for using RAID?
Ans: RAID is an acronym that stands for Redundant Array of Inexpensive Disks or Redundant Array of Independent Disks. RAID is a term used in computing. With RAID, several hard disks are made into one logical disk. There are different ways this can be done. Each of the methods that puts the hard disks together has some benefits and drawbacks over using the drives as single disks, independent of each other. The main reasons why RAID is used are:

To make the loss of data happen less often. This is done by having several copies of the data.
To get more storage space by having many smaller disks.
To get more flexibility (Disks can be changed or added while the system keeps running)
To get the data faster.

Q50.How many disk can be used for RAID 1?
Ans: RAID 1 is usually implemented as mirroring; a drive has its data duplicated on two different drives using either a hardware RAID controller or software (generally via the operating system). If either drive fails, the other continues to function as a single drive until the failed drive is replaced. Conceptually simple, RAID 1 is popular for those who require fault tolerance and don't need top-notch read performance. A variant of RAID 1 is duplexing, which duplicates the controller card as well as the drive, providing tolerance against failures of either a drive or a controller. It is much less commonly seen than straight mirroring.
Hard Disk Requirements: Exactly two hard disks. Any type may be used but they should ideally be identical.

Q51. How RAID 5 works?
Ans: This is the most powerful form of RAID that can be found in a desktop computer system. Typically it requires the form of a hardware controller card to manage the array, but some desktop operating systems can create these via software. This method uses a form of striping with parity to maintain data redundancy. A minimum of three drives is required to build a RAID 5 array and they should be identical drives for the best performance.

Parity is essentially a form of binary math that compares two blocks a data and forms a third data block based upon the first two. The easiest way to explain it is even and odd. If the sum of the two data blocks is even, then the parity bit is even. If the sum of the two data blocks is odd, the parity bit is odd. So 0+0 and 1+1 both equal 0 while 0+1 or 1+0 will equal 1. Based on this form of binary math, a failure in one drive in the array will allow the parity bit to reconstruct the data when the drive is replaced.

With that information in mind, here is an example of how a RAID 5 array would work. Each row in the chart represents a physical block on the drive and each column is the individual drive. The numbers in the table represent the data blocks. Duplicate numbers indicate a duplicated data block. A "P" indicates a parity bit for two blocks of data.

Drive 1 Drive 2 Drive 3
Block 1 1 2 P
Block 2 3 P 4
Block 3 P 5 6

The parity bit shifts between the drives to increase the performance and reliability of the data. The drive array will still have increased performance over a single drive because the multiple drives can write the data faster than a single drive. The data is also fully redundant because of the parity bits. In the case of drive 2 failing, the data can be rebuilt based on the data and parity bits on the two remaining drives. Data capacity is reduced due to the parity data blocks. In practice the capacity of the array is based on the following equation where n is the number of drives and z is the capacity:
(n-1)z = Array Capacity
In the case of three 500 gigabyte hard drives, the total capacity would be (3-1)x500GB or 1000 gigabytes.

Hardware RAID 5 implementations can also have a function called hot swap. This allows for drives to be replaced while the array is still functioning to either increase the drives capacity or to replace a damaged drive. The drive controller then takes time while the array is running to rebuild the data array across the drives. This is a valuable feature for systems that require 24x7 operation.
Advantages:
· Increased storage array performance
· Full data redundancy
· Ability to run 24x7 with hot swap
Disadvantages
· High costs to implement
· Performance degrades during rebuilding

Q52. What is the smallest number of disk required by RAID 5?
Ans: At least 4 disks are required by RAID 5.

Q53. What other types of RAID do you know?
Ans: Types of RAID:
RAID 0
RAID 1
RAID 2
RAID 3
RAID 4
RAID 5
RAID 6
RAID 7
RAID 10
RAID 50
RAID 53
RAID s

Q54. What are the six steps for lesar printing?
Ans: Six steps are
1. Cleaning. The drum is cleaned of any residual toner and electrical charge.
2. Conditioning. The drum is conditioned to contain a high electrical charge.
3. Writing. A laser beam discharges the high charge down to a lower charge, but only in places where toner should go.
4. Developing. Toner is placed onto the drum where the charge has been reduced.
5. Transferring. A strong electrical charge draws the toner off the drum onto the paper. This is the first step that takes place outside the cartridge.
6. Fusing. Heat and pressure fuse the toner to the paper.

Q55. What is the difference between PCI-EX x1 and PCI-EX x16?
Ans: The PCI-EX x1 slot is the very small slot on your motherboard, it is usually used for USB expansion cards, Network adapters and some soundcards. The PCI-EX x16 is used for graphics cards because it has(you guessed it) 16 times the bandwidth to allow better performance in games.