Advanced Computer Applications PC Storage & Output Devices Advanced Computer Applications Lesson 3

DO NOW 9/9 Does a Computer Need an Internal Modem With Cable Internet? Write your definition of a modem. What type of modem you have at home?

OBJECTIVES Identify different types of storage output and other peripheral devices. Understand how hard drives are segmented. Comprehend the different types of modems and how they work.

Four Basic Functions: INPUT Keyboard Mouse Scanner Voice Microphone PROCESSING CPU RAM ROM OUTPUT PRINTER MONITOR STORAGE CD-ROM CD-RW CD-DVD DISKETTES FLASH DRIVES HARD DRIVE TAPE

Hardware Components Storage Devices: When PC is turned off data is lost unless saved onto a more permanent storage device Work like video recorders Retrieve it or record over it Storage Devices: As discussed previously, everything typed in while working with a program is stored in RAM and, therefore, only temporary soon as the power to the PC is turned off, you work is lost unless it has been saved onto a more permanent storage device. These devices work like video recorders in that they record the data onto a magnetic media. Once recorded, the power can be turned off without loss of data. If needed again, you simply retrieve it (play it back) as often as required. If no longer needed, new data can be recorded over it.

Hardware Components Peripherals Device connected to the computer through the “bus” Monitors, keyboards, disk drives, printers and scanners Some are delicate and are mounted directly inside the computer case Video boards, inboard modems, sound cards What are Peripherals? A peripheral is a device connected to the computer through the bus. Many essential components of a PC are peripherals, including monitors, keyboards, and disk drives. Printers and scanners are also peripherals. Some peripherals, because of their small size or delicate nature, are mounted directly inside the computer case. Video boards, inboard modems, and sound cards are devices inside the computer that depend on the bus.

Magnetic Storage Devices Coated with a magnetically sensitive material, such as iron oxide Hard Drive/Disk Most widely used secondary storage device Aluminum platters covered with a thin iron- oxide coating Data is magnetically recorded onto its surface Magnetic Storage Devices are coated with a magnetically sensitive material, such as iron oxide, that reacts to a magnetic field. Hard Drive or Hard Disks: Is the most widely used secondary storage device. A hard disk drive generally consists of aluminum platters covered with a thin iron-oxide coating similar to videotapes or cassettes, which allows data to be magnetically recorded onto its surface. Hard drives come in various storage capacities and are permanently encased to protect them from contamination. Hard disks consist of several hard aluminum platters stacked on top of each other.

Magnetic Storage Devices Hard Disks (Hard Drives) Disk Cartridges Flash Drives Magnetic Tape ZIP Disk Magnetic Storage Devices are coated with a magnetically sensitive material, such as iron oxide, that reacts to a magnetic field. Hard Disks (Hard Drives) Diskettes High-Capacity Floppy disks Magnetic Tape ZIP Disk Disk Cartridges Flash Drives

Hard Drive/Hard Disk How does it read/write data? *NOTE: Sector = Groups or clusters on a track. Tracks Cylinders Cylinders How does it read/write data? How does it read/write data? The heads write the data coming from the disk controller to the platters by aligning magnetic particles on the platter’s surfaces, the heads read data by detecting the polarity of particles that have already been aligned.

Hard Drive/Hard Disk Sectors, tracks, heads, and cylinders: Data is stored in the magnetic coating of the disk Head is used to write and read data Data is organized on a disk in cylinders, tracks and sectors Cylinders are concentric tracks on the surface of the disk Tracks are divided into sectors A hard disk has a head on each side of a disk. Actuator arm is moved by a servo-motor Sectors, tracks, heads, and cylinders: On a hard disk, data is stored in the magnetic coating of the disk. The so-called head, held by an actor arm, is used to write and read data. This disk rotates with a constant turn time, measured in revolutions per minute (RPM). Data is organized on a disk in cylinders, tracks and sectors. Cylinders are concentric tracks on the surface of the disk. A track is divided into sectors. A hard disk has a head on each side of a disk. Nowadays, the actuator arm is moved by a servo-motor (not a step motor which needs more time while swinging in after moving over the desired track). All hard disks have reserved sectors which are used automatically by the drive logic if there is a effect in the media.

Hard Drive/Hard Disk A = Track (Red) B = Sector (Slice) C = Sector Track D = Cluster Each track is divided into a number of clusters that represent the smallest unit of storage that is addressable (can be written to or read). Typically, a cluster is 256 or 512 bytes in length. Sector is the “pie slice” A sector is the basic unit of data storage on a hard disk. The term "sector" emanates from a mathematical term referring to that pie shaped angular section of a circle, bounded on two sides by radii and the third by the perimeter of the circle. An explanation in its simplest form, a hard disk is comprised of a group of predefined sectors that form a circle. That circle of predefined sectors is defined as a single track. A group of concentric circles (tracks) define a single surface of a disks platter. Early hard disks had just a single one-sided platter, while today's hard disks are comprised of several platters with tracks on both sides, all of which comprise the entire hard disk capacity. Early hard disks had the same number of sectors per track location, and in fact, the number of sectors in each track were fairly standard between models. Today's advances in drive technology have allowed the number of sectors per track, or SPT, to vary significantly. Clusters are essentially groupings of sectors which are used to allocate the data storage area. Sector 0 of the diskette or disk contains a special file, the file allocation table (FAT). The FAT tells where the directory to the files on the medium is located and information about how clusters are used. You can't look at sector 0 directly. Video

Magnetic Storage Devices Hard drive storage Trivia: A megabyte equals approximately five hundred typed pages of paper. A gigabyte equals a stack of paper approximately 100 feet high. So a 10-gigabyte hard drive is capable of storing a stack of paper 100 stores high. That’s the equivalent of a 10 story building! A hard drive with 100 gigabytes could hold an entire library floor of journals and magazines, too!

Magnetic Storage Devices Zip Disk Drive- Flash Memory – Used in digital cameras and other devices Uses chips to hold information No moving parts Zip Disk- Like the floppy disk, had a portable disk inside a plastic case. A ZIP disk can hold 100 to 250 megabytes. 250 megabytes is roughly equal to five volumes of encyclopedias! Flash Memory – Used in digital cameras and other devices, uses chips to hold information. You can add information to flash memory in large chunks rather than piece by piece, making storage faster and easier than with other types of memory.

Optical Storage Devices Optical Disks – use laser to read and write information CD-R (Recordable) CD-RW (ReWritable) CD-ROM DVD-ROM DVD-R/DVD-RW Optical Disks – use laser to read and write information. There are 6 types of optical disks: CD-R - Compact Disk Recordable CD-RW - Compact Disk ReWritable CD-ROM - Compact Disk Read-Only Memory DVD-ROM - Digital Video Disk Read-Only Memory DVD-R/DVD-RW - DVD Recordable/DVD-ReWritable CD-R – Compact Disk Recordable, is a CD-ROM disk that doesn’t contain information. A CD-R drive writes information onto the CD-R Disk. A CD-R can hold about the same amount of information that the CD-ROM can hold. Information can only be put on the CD-R and the CD-ROM once. CD-RW – is an optical disk that can record information many times. CD-RW disks are useful for making copies of important information for backup. CD-ROM - (Compact Disk-Read-Only-Memory) disks are input devices. Without special equipment, you cannot save data to a CD-ROM, but can retrieve information from one if you have a CD-ROM drive on your computer. It is an optical disk that can hold up to 1 gigabyte of information . One Gigabyte is = to 700 floppy disks or 300,000 pages of test. CD-ROMS are now common in PC’s because it’s a cheap way to store lots of information. DVD-ROM – Is another type of optical device; however, it can hold up to 17 gigabytes of information. It would take 17 CD-ROMS to hold information in one DVD-ROM. DVD-ROM disks are commonly used to hold movies.

Output Devices Monitor Displays information visually Before 1960 input/output was typically viewed on a printout 1960 DEC attached a TV-style cathode ray tube (CRT) to its PDP-1 minicomputer Today we use a LCD (Liquid Crystal Display) Monitor Displays information visually and is one of the most important components of a computer system. Before 1960, the input/output of a computer was typically viewed on a printout. However, in 1960, the computer company Digital Equipment Corporation (DEC) attached a TV-style cathode ray tube (CRT) to its PDP-1 minicomputer, which shortly thereafter became the standard method of viewing the computer's messages and displays. Most PC users today have an LCD (Liquid Crystal Display) monitor which is much thinner than a CRT.

Output Devices Printers Impact Dot-matrix Ink Jet and Bubble Jet Laser Plotters Printers Next to monitors and disk drives, printers are the most common output devices. A wide variety of printer types is available. Impact printers push images of letters and symbols (cast in metal or plastic) through a ribbon onto the paper. These are the slowest and oldest printer types and generally cannot print graphic images. Dot-matrix printers use a pattern of dots on a print head to imprint through a ribbon onto paper. Like all the other following printer types, they generally can print graphic images. Ink Jet and Bubble Jet printers spray ink onto paper to produce the output. Laser printers use copier-like technology to spread patterns of toner and affix it to paper using heat. Plotters use a needle to draw on paper; they are frequently used by engineers to produce schematic drawings.

Hardware Components Modems (Modulator/Demodular) Allow two or more computers to communicate over telephone lines (and other lines) Digital vs. Analog signals Modulation/Demodulation How Modems Work Modems allow two or more computers to communicate over the telephone lines. Because computers communicate through digital signals and telephones communicate through analog signal, the process is a bit complex. The sending modem must translate the computer’s digital signals (bits) into analog signals for the transmission across the telephone to be successful. At the other end, another modem is used to translate the analog signals back to digital so that the receiving computer can understand the message. The process of translating the signal from digital to analog is referred to as Modulation. The process of translating analog to digital is referred to as Demodulation.

Modems

Modem Types Telephone DSL Cable Wireless Short Video

Famous Persons in Computer History Work on your projects with your partner. Due Thursday 9/11 Directions