P10 CIS 230 Chapter 10 Computer Peripherals Fall 2013

__________________________ are devices that are external to the main processing function of the computer itself. They are external to the CPU. They do not include the CPU, memory and power supply.

T/F. The peripherals in a mainframe computer are similar, except larger, with more capacity. They may be 100 keyboards and terminals and a hard drive array.

T/F. Computer storage is often conceptualized hierarchically, based upon the speed with which data can be accessed.

In the hierarchy of storage, access to CPU __________________________ is essentially instantaneous, since they are actually a part of the CPU.

In the hierarchy of storage, __________________________ is the fastest memory outside the CPU.

__________________________ is a small amount of fast memory that is used to hold current data and instructions.

__________________________ storage refers to both types of RAM, DRAM and SRAM.

T/F. Both DRAM and SRAM provide immediate access to program instructions and data by the CPU and can be used for the execution of instructions.

__________________________ storage refers to hard drives, thumb drives, CD-ROMs/DVDs and magnetic tape.

T/F. Data and programs in secondary storage must be copied to primary storage (memory) for CPU access.

T/F. Most secondary devices are mechanical in nature and are therefore slower than primary memory. The only exception is flash memory.

The location of the desired data is usually not immediately accessible, and the medium must be physically moved to provide access to the current location. The __________________________ is the time needed to find the desired location.

T/F. Most of the access time specified for secondary storage devices consists of seek time.

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State the two advantages of secondary storage.
1) its permanence, or lack of volatility and
2) it may be used to store massive amounts of data

Large capacity flash memory units called “__________________________” have appeared on the market and are starting to supplant disk drives as the long-term storage device of choice in computers where less weight, low power consumption and small size are important. They have the additional advantage of being relatively immune to failure due to physical shock and vibration, and generate less heat and no noise.

A __________________________ consists of one or more flat, circular platters made of glass, metal, or plastic, and coated with a magnetic substance.

T/F. Particles within a small area of the magnetic substance can be polarized magnetically in one of two directions with an electromagnet. An electromagnet can also detect the direction of polarization previously recorded. Magnetic polarization can be used to distinguish 1’s and 0’s.
Electromagnetic read/write heads are used for this purpose.

T/F. A drive motor rotates the disk platter(s) about its central axis.

An __________________________ resembling that of a phonograph record player has the read/write head mounted at the end. It makes it possible for the read/write head to move radially in and out across the surface of the disk. The read/write head motor controls precisely the position of the arm on the disk.

State the two major types of magnetic disks.
1) Floppy disks or diskettes (obsolete)
2) Hard disks

T/F. Most hard disk drives contain several platters, all mounted on the same axis, with read/write heads on each surface of each platter. The actuator arm heads move in tandem, so they are positioned over the same point on the surface. Each side of the platter has an actuator arm that can read and write data for that side of the platter.

With the actuator arm head in a particular position, it traces out a circle on the disk surface as the disk rotates. This circle is known as a __________________________. Each one contains one or more blocks of data.

Since each of the tracks on each surface of the platters all line up, the set of tracks for all of these surfaces form a __________________________.

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On most disks, the surface of the disk platter is divided into equally sized pie shaped segments, known as __________________________. Each one contains one block of data, typically 512 bytes, which represents the smallest unit that can be independently read or written.

In __________________________, the tracks near the center have the smallest number of sectors per track and the number of sectors increases as the tracks get larger. Each track on an IDE drive is designed to have the optimum number of sectors appropriate to the size of the track. There are still 512 bytes per sector for every sector on the drive.

T/F. Each platter on the hard drive is made of rigid material and is precisely mounted.

T/F. The actuator arm heads do not actually touch their side of the platter.

A __________________________ occurs when the actuator arm comes in contact with a platter.

T/F. The hard disks are sealed to prevent dust particles from getting between each side of the platter and the actuator arm head.

T/F. When the disk is stationary, the actuator arm head rests in a parked position on the edge of the drive. The head has an aerodynamic design, which causes it to rise on a cushion of air when the disk platter spins.

T/F. A single data block consists of a header, 512 bytes of data and a footer.

A(n) __________________________ separates the block from neighboring blocks.

The track positions, blocks, and headers must be established before the disk may be used. The process of doing this is called __________________________ the disk.

T/F. The entire track is laid down as a serial stream of bits.

T/F. Many current hard drives include a large buffer memory that can hold several blocks of data.

A __________________________ is a grouping of two or more disk drives. It can be used to reduce overall data access time by sharing the data among multiple disks and also to increase system reliability by providing storage redundancy.

__________________________ is a very useful disk array and can be implemented in two ways. These two ways are a mirrored array and a striped array with parity.

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A __________________________, in a RAID configuration, consists of two or more disk drives where each disk drive is identical. The disks each contain exactly the same data. Reads are faster since some of the data can be obtained from each of the hard drives. All data must be written to each of the hard drives.

A __________________________, in a RAID configuration, requires a minimum of three disk drives. Some of the data is stored on each of the drives along with parity information (error checking information). If one of the drives goes bad, a new drive can be obtained and the data can be reconstructed with the help of the parity information.

T/F. A mirror array (RAID 1) and a striped array with parity (RAID 5) are examples of a fault-tolerant system.

T/F. Optical storage technologies are portable and are capable of packing a relatively large amount of data into a convenient package. It is intended more for offsite archiving, as well as program and file distribution.

A __________________________ is a read-only, removable medium with data storage capacity of about 700 MB. Data are stored in blocks on the disk. The blocks can be arranged in files, with a directory structure similar to that of magnetic disks.

T/F. Rather than concentric tracks, data on a CD-ROM is stored on a single track, approximately three miles long, which spirals from the inside of the disk to the outside. Instead of sectors, the data is stored in linear blocks along the track. Each block is the same length.

T/F. Data is stored on the disk in the forms of pits and lands. They are burned into the surface of the disk with a high-powered laser. The disks are reproduced mechanically using a stamping process. The disk is protected by a clear coating.

T/F. A laser beam is reflected off the pitted surface of the CD-ROM as the motor rotates the disk. The reflection is used to distinguish between the pits and lands, and these are translated into bits.

On a CD-ROM, a “0” bit is represented as a __________________________.

On a CD-ROM, a “1” bit is represented as a __________________________.

T/F. When the laser strikes land, light reflected into the light detector.

T/F. When the laser strikes a pit, light is scattered.

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__________________________ is essentially similar to CD-ROM technology. The disks are the same size and formatted similarly. However, the use of a laser with a shorter light wavelength (visible red, instead of infrared), allows tighter packing of the disk. Each layer can hold approximately 4.7 GB.

T/F. Two layers of data can be placed on the same side of the DVD disk, one underneath the other. In addition, both sides of a DVD-ROM can be used. If both layers on both sides are used, the DVD-ROM capacity is approximately 17 GB. The use of a blue laser extends this capacity to approximately 50 GB.

__________________________ disks were originally designed to provide an inexpensive way for archiving data. WORM disks can be written, however once written, a data block cannot be rewritten. When a file is updated, it is simply written again to a new block and a new directory entry is provided.

T/F. WORM disks work similarly to a CD or a DVD. The main difference is that the disk is made is made up of material that can be blistered by a medium-powered laser. Initially, the entire disk is smooth. When data is to be written, the medium-power laser creates tiny blisters in the appropriate locations. These correspond to the pits in a normal CD-ROM.

State the other types of optical storage technologies that medium-powered laser blister technology is also used.
CD-R, DVD-R and DVD+R
CD-RW, DVD-RW, DVD+RW, DVD-RAM, DVD+RAM, BD-RE

__________________________ is a sequential medium, which makes it impractical for random access tasks. Generally, full system backups are made to it and moved to offsite locations for long term storage. It can be used for archival purposes and for disaster recovery. It can be stored indefinitely.

T/F. Tape cartridges are read serially and are used for data backup.

T/F. When the tape is in the tape drive, ready for operation, it is said to be mounted.

A __________________________ is an image made up of thousands of individual pixels (picture elements) arranged to make a large rectangular screen. Each pixel is a tiny square on it.

T/F. The size of the display is the diagonal length of the screen.

A __________________________ pixel is actually made up of a mixture of different intensities of red, green and blue (RGB). It takes one byte per pixel to represent a 256-color image. 24 bit color would use 8 bits per color and result in more than 16 million colors on the screen and is sometimes described as True Color.

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A __________________________ scale with no shading would require only one 1 bit per pixel (on for white, off for black).

The actual display is produced by scanning and displaying each pixel, one row at a time, from left to right, top to bottom. This method of displaying all the pixels is known as a __________________________. It is essentially identical to the way that television pictures are generated.

Some monitors __________________________ the display, by displaying the odd rows first and coming back and displaying the even rows.

T/F. Interlaced monitors tend to flicker more than noninterlaced ones.

Noninterlaced displays are also sometimes called __________________________.

An alternative to raster scan is __________________________, in which pixels are displayed in whatever order is necessary to trace out a particular image. It could trace a character by following the outline of the character. It is used for object images in CAD/CAM applications. They are sometimes used when printing object graphics-based drawings to a plotter.

T/F. The popularity of what-you-see-is-what-you-get (WYSIWYG) output requires the ready availability of different fonts and flexibility in layout on the screen.

__________________________ technology has become the prevalent means of displaying images.

T/F. In a LCD, a florescent light panel, located behind the display, produces white light.

Explain the operation of a LCD Display.
A polarizing filter in the front of the light panel polarizes the light so that most of it is polarized in one direction.
The polarized light then passes through a matrix of liquid crystal cells. In a color display, there are 3 cells positioned properly for each pixel.
When an electrical current is applied to one of these cells, the molecules in the cell spiral.
The light coming out of the crystal is now polarized in different directions, depending on the strength of the current that was applied to the crystal.
The light is now passed through a red, blue or green color filter.
The final polarizing filter blocks all light that is polarized perpendicular to its preferred direction, the second filter will only pass through the light that is polarized in the correct direction.
Therefore, the brightness of the light is proportional to the amount of polarization twist that was applied by the liquid crystal’s spiral.

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For a(n) __________________________ monitor, there is one transistor per cell in the matrix. It guarantees that each cell will receive a strong charge. It is more expensive and difficult to manufacture. It has a brighter picture.

For a(n) __________________________ monitor, there is one transistor per row and column in the matrix. Each cell is lit in succession. The display is dimmer since pixels are lit less frequently.

T/F. CRT (Cathode Ray Tube) was the most common display technology. It is similar to TVs. CRTs have been replaced by LCDs.

T/F. OLED (Organic Light-Emitting Diode) technology is a new screen technology that is poised to supplement or replace LCD technology in display monitors.

__________________________ technology offers an image that is brighter, with colors that are more vivid and with vastly improved contrast. Despite the improved image, the OLED panel consumes less power, with a package that is even thinner than current flat screen monitors.

LCD technology is __________________________ in the sense that light is generated by a backlight; the light is selectively blocked by the LCD cells in the panel. Leakage in the cells limits the level of darkness that can be achieved and the maximum brightness is limited by the brightness of the backlight.

In contrast, OLED technology is __________________________. OLED technology consists of a thin display panel that contains red, green, and blue LEDs for each pixel with transistors for each LED that generate electrical current to light the LED. The light output is produced directly by these LEDs. The brightness of a pixel is determined by the amount of current supplied by the transistor, which in turn is determined by an input signal indicating the desired level of brightness. The simplicity of the panel, combined with the lack of need of a backlight, result in the thinness of the panel.

T/F. Early printers were derived from typewriters. Printing resulted from the hammer-like physical impact of the character through inked ribbon onto paper.

T/F. Later impact printing used pins that were selectively employed to generate dot matrix representations of the characters on the page. These printers were known as dot matrix printers.

T/F. All modern printing is done using nonimpact printing.

T/F. Like displays, printer output can be character based or graphics based.

T/F. Nearly all modern computer printers produce their output as a combination of dots, similar in style to the pixels used in display.

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Explain the two major differences between dots and pixels.
1) The number of dots per inch printed is generally much higher than the number of pixels per inch displayed. There are 70 to 150 pixels per inch on the monitor and 600 to 2400 dots per inch on the paper.
2) The dots produced by most printers are either on or off and pixels have an infinite range of intensity or brightness.

T/F. The output to many printers takes the form of graphical bitmaps that represent the required pixels directly.

T/F. Some printers have built-in computing capability and can accept data in the form of a page description language, predominately Adobe PostScript or PCL. The controller in the printer can then convert from the page description language to the bitmap within the printer itself. Memory is provided within the printer to hold the bit-mapped image while it is being printed.

State the various types of printers.
Typewriter / Daisy wheels (obsolete)
Dot matrix (also obsolete)
Inkjet
Thermal wax transfer
Dye Sublimation
Laser Printer

__________________________ use impact printing, because printing results from the physical impact of a print head on the paper.

__________________________ squirt boiled droplets of ink as the print cartridge moves across the page to print a row and mechanical rollers move the page downward to print successive rows.

The heat, from the print heads of a __________________________ printer, melts the wax onto ordinary paper.

The heat, from the print heads of a __________________________ printer, melts the dye onto special paper. The dye diffuses in this paper so that the color of dots actually blends together. It can print continuous color tones.

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__________________________ printing is derived from xerography. The major difference is that the image is produced electronically from the computer using a laser or light-emitting diode, rather than scanning a real image with a bright light, as in a copy machine. It requires the interaction of mechanical, electrical and optical technologies. The toner is placed on a negatively charged rotating drum. The drum deposits the toner on positively charged paper as the paper moves through the system.

List the six steps in the operation of a laser printer.
Cleaning
Conditioning
Writing
Developing
Transferring
Fusing

In the __________________________ step of a laser printer printing a page, the drum is cleaned of any residual toner with a rubber blade and a fluorescent lamp removes any electrical charge remaining on the drum.

In the __________________________ step of a laser printer printing a page, the entire drum is uniformly charged to -600V by the primary (or main) corona wire located inside the toner cartridge.

In the __________________________ step of a laser printer printing a page, the laser printer controller uses a laser beam and a series of mirrors to create the image of the page on the drum.

In the __________________________ step of a laser printer printing a page, the developing roller, located inside the toner cartridge, has a magnet inside of it that attracts the iron particles in the toner. As the developing roller rotates by the drum, the toner is attracted to the areas of the drum that have been exposed by the laser, creating the print image on the drum.

In the __________________________ step of a laser printer printing a page, a strong positive charge is placed on the paper patiently waiting to be printed. The paper attracts the negatively charged toner particles from the drum.

In the __________________________ step of a laser printer printing a page, heat and pressure are used to fuse the toner to the paper.

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State several user input devices.
Keyboards
Pointing devices Mechanical Mouse Optical Mouse Trackball Game Controller
Light pens
Graphics tablets & Touch Screens
Scanners

Keyboards consist of a number of switches and a keyboard controller. The keyboard controller is built into the keyboard. When a key is pushed, a signal called a __________________________ is sent to the controller. A different signal is sent when the key is released. They allow keys to be used in combination.

T/F. A mouse is the best known pointer device.

As the __________________________ is moved across the surface, the roller ball protruding from the bottom also moves. Two wheels, mounted at right angles from each other, touch the roller ball and move with it. These wheels are called encoders. As the encoders move, they generate a series of pulses. The number of pulses corresponds to the distance that it has moved.

T/F. One encoder records the right-left movement and the other encoder records the up-down movement. The pulses are sent to a program in the computer to interpret the current location of the mouse.

T/F. Some encoders use a tiny light and sensor to create the pulses while others use a tiny mechanical switch.

A __________________________ is pointed at a screen to identify a position on the screen. By moving it around the screen, a cursor can be made to follow it. It can be used to point to a target, such as a control button on the screen, and can be used as a drawing tool. It is not actually capable of telling the system its position. Instead, the software program that is used with it rapidly generates pixels of light on the display screen at known locations in the area where it is believed to be pointing.

T/F. Graphics tablets use a variety of techniques, including pressure sensitive sensors, optical sensors, magnetic sensors and capacitive sensors to determine the location of a pen on the pad. They are particularly suited for drawing.

T/F. A similar mechanism is used for the touch pads commonly found on laptop computers.

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T/F. Touch screens provide a capability similar to those of graphics tablets, but with the sensing mechanism attached directly to the display screen, allowing the user to point directly to an object on the screen.

__________________________ are the primary means used to input paper images.

State the three primary types of scanners.
Flatbed scanners
Sheet-fed scanners and
Hand-held scanners

The mechanism of a __________________________ consists of a light source and a row of light sensors. As the light is reflected from individual points on the page, it is received by the light sensors and translated to digital signals that correspond to the brightness of each point. Color filters can be used to produce color images, either by providing multiple sensors or by scanning the image three times with a separate color filter for each pass.

T/F. The resolution of a scanner is similar to that of printers, approximately 600 – 2400 points per inch.

T/F. From the perspective of a computer, a network is simply another I/O device, a device that, like a disk, offers input to applications on the computer and receives output from applications on the computer.

T/F. Like other I/O devices, there is a network interface card (NIC) that handles the physical characteristics of the connection and one or more I/O drivers that manage and steer input data, output data and interrupts.

The __________________________ is responsible for the electrical signals that connect the computer to the network, directly or through a communication channel. It is also responsible for the protocols, implemented in hardware, that define the specific rules of communication for the network. These protocols are called medium access control protocols (MAC protocols).

Every NIC and network device has a unique physical address that is burned into the device at the factory. This physical address is referred to as the __________________________ address.