CSC 1010 1st EditionExam # 3 Chapters: 7 & 8Chapter 7 What is storage?Media and devices used to store and retrieve data, instructions, and informationWhat unit is used to define the measurement of storage? A Byte. How does storage differ from memory?Memory is also called primary storage or RAM. Storage (also called secondary storage) stores items for future use, rather than temporarily. Storage is also nonvolatile, rather than volatile. When you want to work with a file, you read it from storage and place it in memory. When you are finished with the file, you write it from memory into storage.How does volatility compare?Screen display and contents of most RAM (memory) is erased when the power is off, and contents of storage are retained when the power is off. What is a storage device and a storage medium?- Storage device: Hardware that records and retrieves items to and from a storage medium- Storage medium: Physical material on which a computer keeps data, instructions, and informationWhat is reading and writing?- Reading: Process of transferring data, instructions, and information from a storage medium into memory. It serves as a source of input.- Writing: Process of transferring items from memory to a storage medium. It serves as a source of output.What is access time?The amount of time it takes device to locate item on disk. Access time defines speed of disk storage device. The follow devices have access time:o Tape (slowest, least expensive)o Floppy Disko Compact Disco Hard DiscWhat is capacity?The number of bytes (characters) storage medium can hold:o Kilobyte KB – 1 thousando Megabyte MD – 1 milliono Gigabyte GB – 1 billiono Terabyte TB – 1 trilliono Petabyte PB – 1 quadrillionWhat is a floppy disk?It is a portable, inexpensive storage medium. Today’s standard disk is 3.5” wide. HD (High Density disk) Stores 1.44MB. What are the parts of a floppy disk?A floppy disk is thin, circular, flexible film enclosed between two liners.How are floppy disk drives designated?- One floppy drive: drive A- Two floppy drives: drive A and drive BWhat does it mean for a floppy disk to have double density?One can use both sides. What is the metal flap on a floppy disk called? It is called a right protected knotch. How does a floppy disk drive work?1: Shutter moves to expose recording surface on disk2: Signal sent to control movement of read/write heads and disk3: If write instruction, circuit board verifies whether disk can be written to4: Motor causes floppy disk to spin5: Motor positions read/write heads over correct location on disk6: Read/write heads read data from or write data on the floppy diskWhat are tracks and sectors?A track is narrow recording band that forms full circle on disk surface. A sector can store up to 512 bytes of data. 80 tracks per side X 18 sectors per track X 2 sides per disk X 512 bytes per sector = 1,474,560 bytes = 1.44 MBWhat is formatting?Formatting is the process of preparing disk for reading and writing. Formatting marks bad sectors as unusable.How do you care for a floppy?Proper care helps maximize disk’s life. A Floppy disk can last at least seven years. Always abide by the following: 1. Never open the shutter and touch the disk’s recording surface2. Avoid exposure to heat and cold3. Avoid exposure to magnetic fields4. Avoid exposure to contaminants such as dust, smoke, or salt air5. Keep disks in a storage tray when not using themWhat is a write-protect notch?A wrote-protect notch is a small opening with a cover that you slide. It protects floppy disks from being erased accidentally. Notch open means you cannot write on the disk, and notch closed means you can write on the diskWhat is a high-capacity disk drive?A high-capacity disk drive uses disks with capacities of 100 MB and greater. It is primarily used to backup files and transfer files. i.e. Zip drive; can store 100 MB or 250 MB of dataWhat is a backup?A backup is a duplicate of file, program, or disk that you can use if original is lost, damaged, or destroyed.What is a hard disk?A hard disk consists of several inflexible, circular platters that store items electronically and has high-capacity storage (20 – 100 GB). Components are enclosed in airtight, sealed case for protection.How does a hard disk work?1: Circuit board controls movement of head activator and small motor2: Small motor spins platters3: When software requests disk access, read/write heads determine location of data4: Head actuator positions read/write head arms over correct location on platters to read or write dataWhat is a cylinder?A cylinder has the location of a single track through all platters. A single movement of read/write head arms can read same track on all platters.What is a head crash?A head crash occurs when read/write head touches platter surface. Spinning creates cushion of air that floats read/write head above platter. Clearance between head and platter is approximately two millionths of an inch (a gap is half the diameter of a dust particle). What is a disk cache?A portion of memory processor uses to store frequently accessed itemsWhat is a partition?A formatted hard disk divided into separate areas called partitions. Each partition functions as if it were aseparate hard disk drive. - Drive C: Designation for first partition or for a single partition on hard disk- Drive D: Designation for second partition on hard diskWhat is a removable hard disk?A disk drive in which a plastic or metal case surrounds the hard disk so you can remove it from the drive. It is used for backup or to transfer files.How does RAID work?RAID is a disk system that duplicates data, instructions, and information to improve data reliability ensuring that data is not lost if one drive fails. - Mirroring has one backup disk for each disk- Striping stores data across multiple disksWhat Windows utilities maintain a hard disk drive?- Backup- Disk Cleanup- Disk Defragmenter- Scheduled TasksWhat is an Internet hard drive?It is a service on Web that provides storage to computer users. Most offer free storage, and revenues come from advertisers. What are advantages of an Internet hard drive?An internet hard drive has: - Large audio, video, and graphics files can be downloaded to an Internet hard drive instantaneously- Files can be accessed from any computer or device with Web access- Others can be authorized to access data from your Internet hard drive- Allows offsite backups of dataWhat is a compact disc (CD)?It is a storage