Computer Interview Questions and Answers

Answer - 31 : - The size of computer data is measured in bytes. Larger units of bytes are often measured in kilobytes, megabytes, and gigabytes. However, the size of these units can be somewhat ambiguous. For example, a kilobyte can equal 1,024 bytes or 1,000 bytes, depending on the context in which it is used. A megabyte may equal 1,048,576 bytes or 1,000,000 bytes. In 1998, the International Electrotechnical Commission (IEC) introduced new units of measurement to avoid this confusion. These units are all exact measurements and cannot be estimated like kilobytes, megabytes, and gigabytes. The new IEC units are listed below: byte (B) kibibyte (KiB) - 2^10 mebibyte (MiB) - 2^20 gibibyte (GiB) - 2^30 tebibyte (TiB) - 2^40 pebibyte (PiB) - 2^50 exbibyte (EiB) - 2^60 zebibyte (ZiB) - 2^70 yobibyte (YiB) - 2^80 For a list of the more commonly used, but also more ambiguous SI units of data storage

Answer - 32 : - Even small images take up as much space as several pages of text. This is because each dot (or pixel) in the image has a certain value, which means there are lot of values to store. For example, a bitmap image that is 100 x 200 pixels in size must store 20,000 values. An image that is 640 x 480 must store 307,200 pixels. Text documents, on the other hand, require a value for each character. Since each character takes up one byte of space, a page with 2,000 characters equals 2,000 bytes or about two kilobytes (2K). Compare that to a small 100 x 200 bitmap (.BMP) image, which takes up 124K. Fortunately, JPEG and GIF compression can significantly reduce the file size of images. For example, the file above is reduced to 8K as a JPEG (with a compression ratio of 60%) and 12K as a GIF image. Still, it would take 4 pages of text to equal one small JPEG image and 6 pages or text to equal the same size GIF. If you're developing a Web site, it is important to realize that images will always take up the majority of your space.

Answer - 33 : - No matter what kind of Mac or PC you have, you can use them on the same network. However, if you would like the computers to "see" each other on the network so you can transfer files between the two systems, the Mac will need to be running Mac OS X 10.3 or later. Mac OS X 10.3 (Panther) allows the Mac to join a Windows network just like a Windows computer. As long as Windows Networking is enabled on the Windows machine, you can connect it with the Mac. First, make sure you are in the Finder on the Mac (it should say "Finder" next to the apple in the upper-left corner of the screen). Then choose "Connect to Server..." from the Go menu in the menu bar, or use the shortcut Command-K. This will bring up a window allowing you to type in the IP address of the computer you would like to connect to. If you are unsure of the IP address of the Windows machine, click the "Browse" button located near the bottom of the window. Clicking the Browse button opens a Network window in the Finder that shows the current servers on the network. This window can also be opened by clicking the "Network" icon in the left sidebar of any open Finder window. Click the "Servers" icon in the Network window to view all available servers. Any Windows computers with Windows client networking enabled should show up here. Double click the icon for the computer you want to connect to and you'll be prompted to mount a virtual disk on you desktop. You may also have to enter a username and password, if required by the Windows machine. This login can be specified in the Windows networking preferences or you can enter the administrator login for the Windows machine. Once you have successfully connected, a shared drive or folder will appear on your Mac's desktop. Double-click the icon to open the drive or folder and view its contents. You should be able to drag and drop items to and from the window, just like any other folder on you local hard drive.

Answer - 34 : - Nobody wants to buy a fast computer just to have it slow to a crawl over time. If your computer is not performing like it used to, there are a number of causes that could be causing the sluggish performance. Here are a few: A nearly full hard drive. If your hard drive is almost completely full, it is likely many of your files are fragmented. This is because as the hard drive fills up, there are fewer open blocks of space to write additional files to. The result is that new files get written on different sections of the drive (file fragmentation). Your computer takes longer to read fragmented files, since it has to scan more of the hard drive. This can cause your computer to slow down significantly. Solution: Delete unnecessary files and run a file defragmentation/optimization program such as Norton Speed Disk. Spyware and viruses. If you're using Windows, there is a high probability that your operating system has been infected by various spyware programs or viruses. These programs run discreetly within your system, taking up CPU and memory, slowing your computer down. They usually find their way into your computer through your Internet connection and are often hard to detect. Viruses and spyware can cause anything from a small drop in your computer's performance to bringing your machine to grinding halt. Solution: Use Windows Update to download the latest security updates and install at least one antivirus program and antispyware program to find and remove malicious files. Low memory (RAM). Everything that happens on your PC has to go through the computer's memory at some point. So if you don't have a lot of RAM, it may cause bottleneck when your computer needs to move a lot of information at once. Typically, newer software programs require more RAM than older programs, since they often have more features and better graphics capabilities. If your computer could run old programs well, but is having trouble running new programs, upgrading your memory is the first thing you should do. It's relatively inexpensive and can breath new life into your machine. Solution: Add more RAM to your computer. Make sure you get the correct type of memory for your machine -- check the size, type, number of pins, and speed of the RAM. If none of these solutions seem to help boost your computer's performance, you may have

Answer - 35 : - Infrared technology is what most TV remotes use. The distance an infrared signal can travel varies based on the strength of the remote, but is usually less than 50 feet for household electronics. In order for an infrared signal to be detected, there must be a direct line of sight between the transmitter (remote) and the receiver (TV). If there is a wall or large object between them, the signal will not pass through it. Bluetooth, on the other hand, uses a radio frequency, which allows transmission through walls and other objects. The standard range of a Class 3 Bluetooth device is about 30 ft., which makes it ideal for syncing PDAs with computers, using wireless cell phone headsets, and enabling handsfree cell phone use inside Bluetooth-enabled automobiles. Because Bluetooth technology is based on a standard 2.4 GHz frequency, different Bluetooth devices can typically communicate with each other, regardless of the manufacturer. Most infrared devices only work with proprietary equipment. While Bluetooth is well on its way to replacing infrared in many different areas, the technology is not meant to be used for wireless networking. Instead, Wi-Fi technology, which has a larger range and higher bandwidth than Bluetooth, is the standard that most wireless networking equipment uses.

Answer - 36 : - Hibernate and Standby are two different sleep options that Windows XP offers. Hibernate saves an image of your desktop, including all open windows and files. Then it powers down your computer just as if you had turned it off. When you turn your computer on again, your windows and files are open just as you left them. Standby is a more traditional sleep mode, as it reduces the power your computer uses to almost nothing. When you select Standby, the power to your screen, hard drive, and peripheral devices is cut. However, the power to the computer's memory (RAM) is maintained so your open files stay open.

Answer - 37 : - Computers are digital devices, meaning they perform all calculations using ones and zeros. This method of computing is referred to as the "binary system," and is the heart of all digital technology. Devices such as hard drives, CD recorders, and Mini DV camcorders are digital devices, and therefore record data digitally, as ones and zeros. VCRs, tape players, and record players, on the other hand, are analog devices. This is because they record data linearly from one point to another. Imagine a bumpy line moving from left to right -- that is what an analog audio recording would look like. Analog devices read the media, such as tapes or records, by scanning the physical data off the media. For example, a record player reads the bumps and dips in the grooves of the record and translates the information into an audio signal. An audio CD player, however, reads ones and zeros off a compact disc and translates that information into an audio signal. However, the ones and zeros only estimate the actual soundwave, whereas a record player records the exact sound. When you hear terms like "sampling rate" or "bit rate," these refer to how many times per second the digital signal is sampled. The higher the number, the more accurate the estimate is, which translates into higher quality sound or video. So why is digital technology used if analog provides a better representation of the recorded information? Well, since computers perform digital computations, they can only work with digital media. Therefore, all analog audio or video media must be converted to digital to work on a computer. Once the information is digital, computers can be used to edit the data and create effects that were never possible with analog media. Digital media is non-linear, which means it can be edited or played back starting at any point, which can be a huge timesaver compared to working with tape. Digital information also does not "wear out" after repeated use like tapes or records do, which results in much better longevity for digital media. To summarize, a digital signal is an estimation of analog data. Digital recordings are made with ones and zeros, while analog recordings are made with linear bumps and dips. While digital information is not as exact as analog information, it can be used with ot

Answer - 38 : - A raster graphic, which is made up of a specific number of pixels cannot be translated into a vector graphic, an image made up of paths. That being said, some programs like Macromedia Flash can create paths out of raster graphics so that they can be manipulated as vector images. This conversion typically reduces the image's size significantly, but different areas of the image are approximated, giving the image a stained-glass look. While it is possible to create a vector image (i.e. an EPS file) from a raster graphic (i.e. a JPEG image), an exact conversion is not possible. Because of the approximations made in the conversion process, a scaled up vector version of an original raster graphic would most likely look worse than just scaling the raster graphic itself. A quick tip if you're using Photoshop -- increasing the image size by 10% at a time often yields better results than just scaling the full amount at once.

Answer - 39 : - Kbps stands for "kilobits per second," while Mbps stands for "megabits per second." Because one megabit is equal to 1024 kilobits, 1.0 Mbps is over 1000 times faster than 1.0 Kbps. Note that the lowercase "b" in Kbps and Mbps means "bit," not byte. One byte is equal to eight bits. For example, 2 MBps equals 16 Mbps. This is a small but important difference to be aware of. Data transfer rates are typically measured in bits, while data storage capacity is usually measured in bytes.

Answer - 40 : - Many people think that there are 1000 bytes in a kilobyte. After all, "kilo" means 1000. In most cases, this approximation is fine for determining how much space a file takes up or how much disk space you have. But there are really 1024 bytes in a kilobyte. The reason for this is because computers are based on the binary system. That means hard drives and memory are measured in powers of 2. For example, 2^0 = 1 2^1 = 2 2^2 = 4 2^3 = 8 2^4 = 16 2^5 = 32 2^6 = 64 2^7 = 128 2^8 = 256 2^9 = 512 2^10 = 1024 Notice how 2^10 is 1024. Therefore, 2^10, or 1024 bytes compose one kilobyte. Furthermore, 1024 kilobytes compose one megabyte, and 1024 megabytes compose one gigabyte. For most practical purposes, you can estimate 1024 to 1000. But correcting someone who says there are 1000 bytes in a kilobyte is a great way to impress your friends.