Data Formats PDF

IT1910 Data Formats Data, in computer terms, is a fact, figure, or information that is represented in a set of bits – ones and zeros. Wires and circuits bring forth these bits as electrical pu...

IT1910 Data Formats Data, in computer terms, is a fact, figure, or information that is represented in a set of bits – ones and zeros. Wires and circuits bring forth these bits as electrical pulses in the computer system. These bits can be a file, information, or instruction. The user can edit, store, and delete data to meet his/her specific needs. Data in human form is entered to a computer using a keyboard, a mouse, or any other input device. From the human form, computers manipulate data to convert it to their own representation, which is in binaries of ones and zeros. General Considerations In order to follow the process of data, some considerations of each data flowing in the computer systems should be listed. 1. File Type – It is a name given to a specific kind of file. It may be either of the following examples: − Audio and video files − Image file − Compressed file − System-related and programming files − Disc and media files − Word processor and text files − Executable file − Presentation and spreadsheet files Terminologies for File Type a. File Name – It is a unique file identifier and may be named by a human or a computer. b. File Extension – It is a 1- to 4-letter character identifier for the specific file type. c. File Extension Icon – It is a common identifier for file extension. d. File Association – It is a program associated with the file extension. 2. File Format – It is a structure or layout of a computer file in terms of how data is contained and organized. The structure of a typical file may include a header, metadata, a saved content, and an end- of-file (EOF) marker. The data stored in the file depends on the purpose of the file format. 3. Metadata – It provides additional information about a certain item’s content. The other terms for metadata are descriptions, keywords, tags. (Example: JPEG – dimensions, date created, date accessed, color depth, etc.) 4. File Attributes – These are settings associated with computer files that grant or deny certain rights to how a user or the operating system can access that file. a. Read-only – It allows a file to be read, but nothing can be written to the file or changed. b. Archive – It tells Windows Backup to back up the file. c. System – It is a system file. d. Hidden – It is a file that cannot be seen when doing a regular directory. Classifications of Data As alphanumeric characters As a visual image (still and moving) As audio Internal computer data Data as Alphanumeric Characters Data are entered as characters, symbols, number digits, and punctuation. Specific input devices and methods are used to create these. (e.g., Keyboard, keypads, on-screen keys, magnetic card stripes, etc.) 02 Handout 1 *Property of STI  [email protected] Page 1 of 3  IT1910 Examples: 1. American Standard Code for Information Interchange (ASCII) was originally developed as a standard by the American National Standards Institute (ANSI). ANSI has also defined 8-bit extensions to the original ASCII codes that provide various symbols, line shapes, and accented foreign letters for the additional 128 entries. 2. Extended Binary Coded Decimal Interchange Code was developed by IBM. Its use is restricted mostly to IBM and IBM-compatible mainframe computers and terminals. 3. Unicode supports approximately a million characters, using a combination of 8-bit, 16-bit, and 32-bit words. It divides its character encodings into sixteen 16-bit code pages, called planes, which allows space for about a million characters. Data as Visual Data Images used within the computer fall into two (2) distinct categories: Bitmap objects are images (e. g., photographs and paintings) that are characterized using an image scanner, digital camera or mobile device, or video camera frame grabber. Graphical objects are images made up of graphical shapes (e. g., lines and curves) that can be defined geometrically. Examples: 1. Graphics Interchange Format (GIF) was first developed by CompuServe in 1987 as a proprietary format that would allow users to store and exchange online bitmap images in 256 colors on different computing platforms. Now, it is extensively used on the Web due to its animated frame-by-frame images. 2. Portable Network Graphics (PNG) is the best known compressed alternative to GIF. PNG can store up to 48 bits of color per pixel and can store a transparency percentage value and a correction factor for the color in a monitor or printer. 3. Joint Photographers Expert Group (JPEG) employs a compression algorithm to reduce the amount of data stored and transmitted. This algorithm reduces the image resolution under certain circumstances, particularly for sharp edges and lines, which makes JPEG more suitable for the representation of highly detailed photographs and paintings. Video images are a result of a sequence of bitmap image frames. The video format is determined by a codec or encoder/decoder algorithm referred to as a “container.” The container serves as a superstructure to encode, decode, hold, and stream video. It serves both video and audio and may support multiple codecs. Data as Audio Data Sound can be stored in digital form on storage media. Since the original sound wave is analog, conversion is needed to make it in digital form, where it is then sampled electronically at regular time intervals. Each time a sample is taken, it is measured by the ADC (Analog-to-Digital Converter) that converts the analog value to a digital (binary) equivalent (consists of sampling, quantization, and encoding). Sampling lays out of the analog signal in a graph. Quantization layers the discrete signal in the analog signal with less margin of error. Encoding converts discrete signals into highs (1) and lows (0), hence the binary equivalent of a time- bound discrete signal. 02 Handout 1 *Property of STI  [email protected] Page 2 of 3  IT1910 Internal Computer Data These are data types represented as interpretation from programming languages. Here are the factors to consider: The actual operations that the computer processor is capable of performing The data types that are supported by the programming language to create the application program. These are the simple data types: 1. Boolean – constant values (true/false) 2. Char – alphanumeric character code 3. Enumerated – user-defined data type 4. Integer – whole numbers (+ / -) 5. Real / Float – numbers with a decimal portion Data Compression Lossless algorithm compresses the data in such a way that the application of a matching inverse algorithm restores the compressed data exactly to its original form. Lossy algorithm operates on the assumption that the user can accept a certain amount of data degradation as a trade-off for the savings in a critical resource, such as storage requirements or data transmission time. References: A/D Converter and D/A Converter (n.d.). In ROHM Co., Ltd.’s website. Retrieved 2019, May 17 from https://www.rohm.com/electronics-basics/ad-da-converters/what-are-ad-da-converters Berekovic, M., Buchty, R., Hamann, H., Koch, D., & Pionteck, T. (2018). Architecture of computing systems – ARCS 2018 proceedings. Switzerland: Springer Nature. Christensson, P. (2011, March 15). File format definition. Retrieved from https://techterms.com/definition/file_format on May 17, 2019 Christensson, P. (2011, March 15). File type definition. Retrieved from https://techterms.com/definition/file_type on May 17, 2019 Computer Hope (2018). What are the most common file types and file extensions? [Web log post]. Retrieved 2019, May 17 from https://www.computerhope.com/issues/ch001789.htm Elahi, A. (2018). Computer systems - Digital design, fundamentals of computer architecture and assembly language. Switzerland: Springer Nature. Englander, I. (2014). The architecture of computer hardware, systems software & networking (5th ed.). New Jersey: Wiley. Ishida, R. (2010, August 12). Character encodings: Essential concepts. Retrieved from https://www.w3.org/International/articles/definitions-characters/ on May 17, 2019 Patterson, D. & Hennessy, J. (2017). Computer organization and design – The hardware/software interface. Massachusetts: Elsevier. [Techquickie]. (2018, September 28). Video file formats - MP4, MOV, MKV [Video File]. Retrieved from https://www.youtube.com/watch?v=hvgxn8v--8Q on May 17, 2019 WAVE PCM soundfile format (n.d.). In Soundfile: Basic Audio Programming in C++. Retrieved from http://soundfile.sapp.org/doc/WaveFormat/ on May 17, 2019 Yadin, A. (2016). Computer systems architecture. Florida: CRC Press. 02 Handout 1 *Property of STI  [email protected] Page 3 of 3