Computer Files and Data Storage

Section A Data, Information, and Files CHAPTER 4 Computer Files and Data Storage Page 158

Section A Data, Information, and Files Chapter 4 SectionPREVIEW Section D Section A You will be able to: • Correctly use the terms “data” and “information” • Create valid file names under DOS and Windows • Explain how wildcards and file extensions simplify file access • Determine if a file is an executable file or a data file Page 158

Data and Information: Technically Speaking Aren’t data and information the same thing? Chapter 4 Section A • Data is words, numbers, and graphics that describe people, events, things, and ideas. • used by computers • Information is the words, numbers, and graphics used as the basis for human actions and decisions. • used by humans Page 160

Computer Files What kinds of files are stored on a computer? Chapter 4 Section A • File - named collection of data that exists on a storage medium such as a hard disk or floppy drive Page 160

File Naming Conventions May I use any name I want when I create my own files? Chapter 4 Section A • Filename • unique set of letter and numbers • identifies a file • describes the file contents • Filenameextension further describes the file contents. • separated by the filename with a dot • You must provide a valid filename that adheres to rules or filenamingconventions. Page 161

Wildcards Is * * a filename? Chapter 4 Section A • The asterisk is a wildcard character used to represent a group of characters in the filename or extension. • Wildcards are handy for finding specific files on a hard disk. Page 162

File Extensions and File Types Why do I need to know about file extensions? Chapter 4 Section A You can access files efficiently if you are familiar with the characteristics of file categories. Page 163

Executable Files How do I use executable files? Chapter 4 Section A • An executable file contains the program instructions that tell a computer how to perform a specific task. • Most have .exe or .com extensions. Executable files have .exe file extensions Page 163

Data Files How do I use data files? Chapter 4 Section A • A data file contains words, numbers, and pictures that you can view, edit, save, send, and print. • Passive, unlike executable files which are active • created using application software • receive data files on CD-ROMS such as clip art • You manipulate a data file using the same software that was used to create it. Page 164

Data Files How do I use data files? Chapter 4 Section A Section A • The standard method for opening a data file is to start an application, then use the open command. • A generic filename extension indicates general type of data contained in a file. • a .bmp could be opened in Microsoft Paint or MicroGrafx Picture Publisher Page 165

Data Files How do I use data files? Chapter 4 Section A • An application-specificfilenameextension is associated with a particular application Application- specific filename extensions Page 166

Configuration Files, and Program Modules What other kinds of files will I find on my computer? Chapter 4 Section A • Other files are necessary for hardware and software operations and should not be deleted. Page 167

Section B File Manager Utility Software CHAPTER 4 Computer Files and Data Storage PARSONS/OJA Page 168

Section B File Manager Utility Software Chapter 4 SectionPREVIEW Section D Section B You will be able to: • Describe the difference between logical and physical file storage Page 168

Section B Worksheets File Manager Utility Software Chapter 4 Section B • File manager utility software • provided by your computer operating system • helps you locate, rename, move, copy and delete files Page 168

Device Letters Why do storage devices have letters? Chapter 4 Section B • A storage device, such as a floppy disk drive, a hard drive, and a CD-ROM drive, is identified by a letter called a device letter. • floppy disk drive = A • main hard disk = C • additional storage devices = D through Z Page 168

Directories and Folders How can I get a list of files that are stored on a disk? Chapter 4 Section B Section B • An operating system maintains a list of files called a directory for each disk, CD-ROM or DVD. • Directory includes • filename • filename extension • date and time file was created • file size Page 169

Directories and Folders How can I get a list of files that are stored on a disk? Chapter 4 Section B Section B Operating system’s file manager utility displays lots of information about the files stored on a computer Page 169

Directories and Folders How can I get a list of files that are stored on a disk? Chapter 4 Section B Section B • Root directory • main directory of a disk • provides a useful list of files • Folders - smaller lists within directories • A folder is separated from a drive letter and a filename by a backslash (\). Page 169

Directories and Folders How can I get a list of files that are stored on a disk? Chapter 4 Section B Section B A file specification (path) is the drive letter, folder, filename, and extension that identifies a file. A:\Word\Gumbo.doc drive letter extension filename subdirectory (folder) Page 170

Storage Models How does file manager utility software depict files and folders? Chapter 4 Section B • File manager utility software provides a metaphorical view of the files stored on a computer. • also called logical models • filing cabinet • tree structure Page 170

Storage Models How does file manager utility software depict files and folders? Chapter 4 Section B A file cabinet metaphor depicts a storage device as a drawer of a filing cabinet containing folders and documents. Page 170

Storage Models How does file manager utility software depict files and folders? Chapter 4 Section B • Visualize a disk directory as a tree. • trunk and branches are folders • leaves are files You can visualize the directory of a disk as a tree on its side. Page 171

Storage Models How does file manager utility software depict files and folders? Chapter 4 Section B Windows Explorer Page 172

Using File Manager Utility Software How do I use file manager utility software? Chapter 4 Section B • Find - to locate a file • Rename - to change the name • Copy - to copy a file • Move - to move file from one folder to another • Delete - when you no longer need a file Page 172

Section C How Computers Store File Data CHAPTER 4 Computer Files and Data Storage Page 174

Section C How Computers Store File Data Chapter 4 SectionPREVIEW Section D Section C You will be able to: • Describe the difference between logical and physical file storage • Discuss how the directory and the FAT help you access files Page 174

Section C How Computers Store File Data Chapter 4 Section C • The data for a single file can be scattered all over the surface of a disk. • Physical storage - way computer store data on a disk. • Logical storage - conceptual model of files and folders. Page 174

Storage Terminology What are the basic components of a data storage system? Chapter 4 Section C • Storagemedium - the disk, tape, CD, DVD, paper, or other substance that contains data • Storagedevice - mechanical apparatus that records and retrieves data from a storage medium • floppy disk drives • hard disk drives • CD drives • DVD drives • tape drives Page 174

Storage Terminology What are the basic components of a data storage system? Chapter 4 Section C • Storagetechnology - a storage device and the media it uses. • Storing - also known as • writing data (mainframe applications) • saving a file (Windows terminology) • Retrieving - also known as • reading data (mainframe applications) • loading data • opening a file (Windows terminology) Page 174

Bits and Bytes If I enter a letter or number how is it actually stored? Chapter 4 Section C • Computers use codes to convert information into digital data. • series of 1s and 0s • Bit - smallest unit for digitizing data • Byte - 8 bits • A byte represents: • a character • a space • numeral • punctuation Page 174

Magnetic and Optical Technologies How does a computer get the 1s and 0s onto the storage medium? Chapter 4 Section C • 1s and 0s are changed in the surface of the storage medium. • Transformation depends on storage technology. • Magneticstorage - stores data by magnetizing microscopic particles on the disk or tape surface • Read-writehead - mechanism in the disk drive that reads and writes magnetized particles that represent data Page 175

Magnetic and Optical Technologies How does a computer get the 1s and 0s onto the storage medium? Chapter 4 Section C Disk surface Read-write head Storing data on magnetic media Mylar disk Page 175

Magnetic and Optical Technologies How does a computer get the 1s and 0s onto the storage medium? Chapter 4 Section C • Data stored on magnetic media such as floppy disks can be altered by dust, smoke, heat, and mechanical problems. • Some experts estimate that the reliable life span of data stored on magnetic media is about three years. Page 175

Magnetic and Optical Technologies How does a computer get the 1s and 0s onto the storage medium? Chapter 4 Section C • Optical storage stores data as microscopic light spots (lands) and dark spots (pits) on the disk surface. • Data stored on an optical storage device is less susceptible to environmental damage. Page 176

Magnetic and Optical Technologies How does a computer get the 1s and 0s onto the storage medium? Chapter 4 Section C Optical storage devices read data using reflected laser light Page 176

Tracks, Sectors, and Clusters Is data stored in specific places on a disk, tape, or CD? Chapter 4 Section C • Tracks - electronic storage bins • parallel to the edge of the tape • spiral out from the center of the disk • arranged as concentric circles or • Tracks that are arranged in concentric circles are divided into wedge-shaped sectors • Cluster - a group of sectors Page 177

Tracks, Sectors, and Clusters Is data stored in specific places on a disk, tape, or CD? Chapter 4 Section C A formatted disk is divided into circular tracks Page 177

File Allocation Tables How does a computer keep track of the location of every file? Chapter 4 Section C • File allocation table (FAT) - an operating system file that maintains a list of files and their physical location on the disk. • like a table of contents • a damaged FAT results in losing data • Back up data on hard disk. Page 177

File Allocation Tables How does a computer keep track of the location of every file? Chapter 4 Section C • Computer looks for empty clusters to store data • Name of new file and number of cluster are recorded in the FAT • Files that do not fit in one cluster spill over to contiguous or noncontiguous clusters, depending on availability. • Pointers - instructions that point to each piece of the file Page 178

File Allocation Tables How does a computer keep track of the location of every file? Chapter 4 Section C Section C Each colored cluster represents part of a file Page 178

File Allocation Tables How does a computer keep track of the location of every file? Chapter 4 Section C • It takes longer to retrieve a file stored in noncontiguous clusters. • When you delete a file, the clusters’ status becomes “empty” but retains old data until new data is stored. • You may be able to retrieve data using an undelete utility. • Recycle Bin’s Restore feature Page 179

File Allocation Tables How does a computer keep track of the location of every file? Chapter 4 Section C • Files stored in many noncontiguous clusters become fragmented. • drive performance declines • becomes harder to locate clusters • A defragmentationutilityrearranges files in contiguous clusters • improves drive performance Page 179

Section D Disks, Tapes, CDs, and DVDs CHAPTER 4 Computer Files and Data Storage Page 180

Section D Disks, Tapes, CDs, and DVDs Chapter 4 SectionPREVIEW Section D Section D You will be able to: • Select a storage device based on characteristics such as its capacity and access speed Page 180

Section D Disks, Tapes, CDs, and DVDs Chapter 4 Section D There are many types of storage devices, each with unique advantages and disadvantages. Page 180

Section D Disks, Tapes, CDs, and DVDs Chapter 4 Section D • Versatility • can access data from different media • Durability • less susceptible to damage • Storage capacity - maximum amount of data that can be stored on a storage medium • kilobyte = approximately 1000 bytes • megabyte = approximately 1 million bytes • gigabyte = approximately 1 billion bytes • terabyte = approximately 1 trillion bytes Page 180

Section D Disks, Tapes, CDs, and DVDs Chapter 4 Section D • Speed -measured by access time and data transfer rate • Access time - average time it takes a computer to locate data and read it • millisecond = one-thousandth of a second • Randomaccess- ability of a device to jump directly to the track or sector holding the data • floppy disk, hard drive, CD, DVD Page 180

Section D Disks, Tapes, CDs, and DVDs Chapter 4 Section D • Sequentialaccess - reads through from beginning of tape • tape drive • Data transfer rate - amount of data that moves per second Page 180

Floppy Disk Storage Why is it called a floppy disk? Chapter 4 Section D • Floppydisk - round piece of flexible mylar plastic covered with thin layer of magnetic oxide. • sealed in protective casing • also called floppies or diskettes • inside casing is “floppy” • not as speedy as zips • decreased use • Zipdisk - high-capacity floppy disk manufactured by Iomega Corporation. Page 181

Computer Files and Data Storage