Mustafa Sakarya        040050357          Hüseyin Toros        20462        1 09 April 2006        

             Question 1. What is the difference between hardware and software?

             Answer 1. Hardware is the machine that we see when we look at the computer. But a computer without software is not different from a furniture. Software is something that makes this machine work.

             Question 2. What is the difference between system software and application software?

             Answer 2. System software that is main part of software controls the computer and the other application software and includes all of the programs needed to keep a computer running normally. Application software is specific programs that are programmed for special purposes and last users. System software is general; application software is specific parts of software.

             Question 3. Explain the purpose of the power-on self-test (POST)?

             Answer 3. When we start the computer, the system software has to check whether the machine (RAM, disk drives, input-output devices) works or not. POST includes these tests and beeping sound will be produced if any problem exists.

             Question 4. What are the advantages of multitasking?

             Answer 4. If you have a multitasking operation system, you can run more than one application program at the same time such that one application program is a foreground application and the others are inactive.

             Question 5. Explain the difference between full backup and an incremental backup?

             Answer 5. An incremental backup stores all files that have changed since the last full, differential or incremental backup. The advantage of an incremental backup is that it takes the least time to complete. However, during a restore operation, each incremental backup is processed, which could result in a lengthy restore job. Incremental backup provides a much faster method of backing up data than repeatedly running a full backup. Full backup is the starting point for all other backups, and contains all the data in the folders and files that are selected to be backed up. Because the full backup stores all files and folders, frequent full backups result in faster and simpler restore operations. Remember that when you choose other backup types, restore jobs may take longer.

             Question 6. How do commercial software, shareware, freeware, and public domain software differ?

             Answer 6. Commercial software: You must buy before using it. Shareware: You try it for a certain time. If you like it you must buy and can use it for a longer time. Freeware: You do not pay for it but you are restricted not to sell and copy it. Public domain software:

             Question 7. Explain the types of compression algorithms?

             Answer 7. A lossy data compression method is one where compressing data and then decompressing it retrieves data that may well be different from the original, but is "close enough" to be useful in some way. This type of compression is used frequently on the Internet and especially in streaming media and telephony applications. These methods are typically referred to as codecs in this context. This is in contrast with lossless data compression. Depending on the design of the format lossy data compression often suffers from generation loss, that is compressing and decompressing multiple times will do more damage to the data than doing it once. Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. This can be contrasted to lossy data compression, which does not allow the exact original data to be reconstructed from the compressed data. Lossless data compression is used in software compression tools such as the highly popular ZIP file format, used by PKZIP, WinZip and Mac OS 10.3, and the Unix programs bzip2, gzip and compress. Other popular formats include Stuffit, RAR and 7z. Lossless compression is used when it is important that the original and the decompressed data be identical, or when no assumption can be made on whether certain deviation is uncritical. Typical examples are executable programs and source code. Some image file formats, notably PNG, use only lossless compression, while others like TIFF and MNG may use either lossless or lossy methods. GIF uses a lossless compression method, but most GIF implementations are incapable of representing full color, so they quantize the image (often with dithering) to 256 or fewer colors before encoding as GIF. Color quantization is a lossy process, but reconstructing the color image and then re-quantizing it produces no additional loss. (Some rare GIF implementations make multiple passes over an image, adding 255 new colors on each pass.)