Untitled Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What process does a laser printer use to create light and dark spots for toner application?

Halftoning technique

Thermal printing method

Rotating drum exposure (correct)

Inkjet technology

Which color mode is used by printers as opposed to monitors?

HSB

RGB

HSV

CMYK (correct)

What is a key advantage of laser printers over inkjet printers?

More color options

Easier to replace cartridges

Lower initial cost

Higher image resolution and speed (correct)

What type of ink do solid ink printers use?

Melted wax ink Signup and view all the answers

Which of the following printer types is considered best for high-quality photos on special paper?

Dye sublimation printers Signup and view all the answers

What is the primary function of a modem?

To modulate and demodulate data Signup and view all the answers

Why might dye-based inks be considered less advantageous than pigment-based inks?

They fade in sunlight. Signup and view all the answers

Which type of printer best supports rapid, high-quality color prints?

Color laser printers Signup and view all the answers

What is the primary function of support chips within a computer system?

Managing functions like memory control Signup and view all the answers

What is the role of the bus system in a computer?

To facilitate communication among CPU, memory, and I/O devices Signup and view all the answers

Direct Memory Access (DMA) primarily benefits a system by?

Allowing more efficient data transfer between I/O devices and memory Signup and view all the answers

What happens when an I/O device uses the interrupt mechanism?

The CPU halts its operation to execute an interrupt handler routine Signup and view all the answers

What is the purpose of the bus arbiter in a bus system?

To determine which device has control of the bus Signup and view all the answers

The cycle stealing method allows I/O devices to?

Request bus access and interrupt CPU processes Signup and view all the answers

Why are legacy buses like the ISA bus becoming obsolete?

Due to limitations in speed and bandwidth Signup and view all the answers

What performance challenge arises due to the increasing speed of CPUs and I/O devices?

Bus contention issues leading to performance bottlenecks Signup and view all the answers

What is the primary benefit of Zone Bit Recording in magnetic disks?

It allows more sectors per track in outer zones, enhancing capacity. Signup and view all the answers

How does RAID level 1 enhance data reliability?

It duplicates data across primary and backup disks. Signup and view all the answers

Which statement accurately describes floppy disks compared to hard disks?

Floppy disks have heads that touch the media, leading to more wear. Signup and view all the answers

What is the major drawback of RAID level 0?

It lacks redundancy, risking data loss if a drive fails. Signup and view all the answers

What characteristic defines Winchester disks?

They are sealed to prevent dust contamination. Signup and view all the answers

Why did floppy disks become less common in modern computers?

Newer storage technologies have replaced them. Signup and view all the answers

Which of the following best describes RAID's purpose?

To improve disk performance and reliability using multiple disks. Signup and view all the answers

What distinguishes RAID level 2 from other RAID levels?

It uses Hamming code for error correction across drives. Signup and view all the answers

Which modulation technique changes the signal's voltage to represent digital data?

Amplitude Modulation (AM) Signup and view all the answers

What is the difference between baud rate and bit rate in data transmission?

Baud rate refers to signal changes per second, while bit rate is number of bits sent per baud. Signup and view all the answers

What does the term 'full-duplex' in data transmission refer to?

Data is transmitted simultaneously in both directions. Signup and view all the answers

Which of the following is NOT a type of modulation mentioned?

Quantum Modulation Signup and view all the answers

Which process is used to convert incoming analog signals back into digital data?

Demodulation Signup and view all the answers

How does Dibit Phase Encoding transmit data?

By using different phase shifts to represent two bits. Signup and view all the answers

What is the common data rate range for modern modems?

28,800 bps to 57,600 bps Signup and view all the answers

What are start and stop bits used for in serial transmission?

To signify the beginning and end of a character. Signup and view all the answers

What is the primary advantage of ADSL over traditional dial-up?

Higher download speeds than upload speeds Signup and view all the answers

What is the typical downstream speed range one can expect from ADSL?

4-8 Mbps Signup and view all the answers

What is the function of channel 0 in the ADSL channel division?

Reserved for POTS (Plain Old Telephone Service) Signup and view all the answers

What happens to the bandwidth of traditional phone lines when the filters are removed?

It increases, enabling higher data rates Signup and view all the answers

What percentage of the bandwidth in ADSL is typically allocated for downstream use?

80-90% Signup and view all the answers

Which of the following best describes the nature of ADSL modulation?

Data is sent via amplitude and phase modulation Signup and view all the answers

What is the purpose of the Network Interface Device (NID) in an ADSL setup?

To mark the end of the telephone service provider's property Signup and view all the answers

Why do average users experience lower upstream speeds compared to downstream speeds in ADSL?

Most online activities involve downloading more data Signup and view all the answers

What purpose does white balance correction serve in digital cameras?

Adjusts colors to reflect true tones Signup and view all the answers

What type of storage media is commonly used for saving images in digital cameras?

Flash memory or microdrives Signup and view all the answers

Which of the following best describes the purpose of ASCII?

To represent text in computers and telecommunications Signup and view all the answers

Which component of modern digital cameras is primarily responsible for managing lens and flash communication?

Embedded computing power Signup and view all the answers

What does the compression in JPEG format primarily achieve?

Reduces file size with some detail loss Signup and view all the answers

Which of the following is NOT a component of post-capture processing in a digital camera?

Color grading Signup and view all the answers

How many unique characters can ASCII represent?

128 Signup and view all the answers

Which of the following represents a limitation of ASCII?

Designed solely for U.S. usage Signup and view all the answers

Study Notes

Secondary Memory

Addresses limitations of main memory, which is too small for vast amounts of data.
Demand for storage grows with technology advances.
Substantial information (like comprehensive film archive) needs digitization and storage.
Data can reach hundreds of terabytes, exceeding main memory capacity.

Memory Hierarchy

Five-level hierarchy (Registers, Cache, Main Memory, Magnetic Disk, Optical Disk, Tape).
Registers: Fastest, smallest storage (around 128 bytes) accessed at full CPU speed.
Cache Memory: Larger than registers, ranging from 32 KB to a few megabytes, slightly slower than registers.
Main Memory: Holds tens of megabytes to several gigabytes, with access times in the range of tens of nanoseconds.
Magnetic Disks: Serve as primary means for permanent storage, providing several to tens of gigabytes with millisecond access times.
Magnetic Tape and Optical Disks: Primarily for archival storage, with second-level access times and capacity limited only by budget.
Access Time increases when going from registers to tape or optical disks.
Storage Capacity increases downward (Registers → larger magnetic disks → tapes) moving down the hierarchy
Cost per bit decreases as you move down the hierarchy

Magnetic Disks

Storage device with platters coated in magnetizable material.
Disk heads write/read data by magnetizing areas on surface.
Originally large; now much smaller (3-12 cm).
Track: Circular sequence of bits on the disk.
Sector: Each track is divided into sectors (512 bytes of data each).
Components: Preamble (for sync), data, ECC (error correction).

Zone Bit Recording

Tracks divided into zones; outer zones have more sectors per track, increasing capacity.
Manages read/write commands, arm movement, error correction, and remapping of bad sectors.
Perpendicular Recording: Newer technique to increase data density by recording vertically.
Winchester Disks: Sealed drives for dust protection ensuring high surface quality.

Floppy Disks

Originally for mainframe maintenance, quickly became popular for personal computer software distribution.
Physically flexible, hence the name "floppy".
Organized into tracks and sectors.
Unlike hard disks, heads directly touch the surface, resulting in more wear.
Floppy disks were widely used for around 20 years, but newer storage media now replace them.

RAID

Redundant Array of Independent Disks.
Addresses slow disk performance relative to CPU by using multiple disks in parallel.
Enhances disk performance and reliability.
Unlike a Single Large Expensive Disk (SLED), RAID uses multiple disks; it appears as one large disk to the OS.

RAID Levels

RAID Level 0 (Striping): Data split into strips and distributed across multiple drives for higher performance (lower reliability).
RAID Level 1 (Mirroring): Data duplicated across primary and backup disks, offering high fault tolerance and high reliability (lower performance).
RAID Level 2 (Hamming Code Parity): Data split into bits; Hamming code used for error correction; suitable for systems with many synchronized drives (high performance, high overhead).
RAID Level 3 (Single Parity Disk): Uses one parity disk for error correction, all drives are synchronized. Can handle single drive failures, limited to handling one I/O request per time (high reliability, limited performance).
RAID Level 4 (Striping with Dedicated Parity): Strips data with a dedicated parity disk, high fault tolerance, but small updates slow performance due to parity disk bottleneck.
RAID Level 5 (Distributed Parity): Distributes parity information across all disks (eliminates bottleneck), and provides high fault tolerance (best for systems needing high reliability, high performance without parity disk bottleneck)

CD-ROMs

Origins: Initially for television recording, soon popular for computer storage due to high capacity and low cost.
LaserVision and Audio CDs: Early large-diameter optical disks were unsuccessful except in Japan; Philips and Sony launched the Compact Disc (CD) in 1980, becoming the first mass-market digital storage medium using this format.
Red Book Standard: Published technical specifications enabling cross-compatibility among music publishers and electronics, ensuring CD compatibility with various players.
Pit-Land Structure: A low-power laser reads pits (depressions) and lands (flat areas), identifying transitions between them to read binary data; ensuring reliable encoding.
CD-ROM Development: Philips and Sony published the Yellow Book in 1984 for CD-ROM standards, enhancing error correction for data reliability.

CD-Recordables

Emergence: Mid-1990s saw affordable and accessible CD recorders.
Usage: Primarily for data backup, small-scale CD production, and as masters for duplication.
Differences from CD-ROMs: Data is permanent once written, cannot be erased
Structure: 120-mm polycarbonate blanks with grooves for laser guidance.
Reflective Layer: Initially gold (later aluminum) creates reflectivity for data writing.
Dye Layer: Cyanine (green) and pthalocyanine (yellow-orange) dyes simulate pits and lands.
Writing Mechanism: High-powered laser creates dark spots on dye, mimicking data pits.
Compatibility: Can be read by standard CD-ROM drives and audio CD players.

CD-Rewritables (CD-RW)

Purpose: Provides a rewritable CD-ROM alternative, meeting demand for reusable media.
Material: Uses an alloy of silver, indium, antimony, and tellurium; which has two stable states (crystalline and amorphous) with different reflectivities.
Laser Functionality: Three Levels:
High Power: Converts crystalline to amorphous state, creating low-reflectivity "pits"
Medium Power: Reverts alloy to crystalline state, restoring high-reflectivity "lands"
Low Power: Reads data without altering material state.
Cost: CD-RW discs are often more expensive than CD-Rs.
Accidental Deletion: CD-R is preferred for backups due to its write-once nature, reducing the risk of accidental data loss.

DVD

Background: Developed to meet demand for high-capacity, high-quality optical storage.
DVD Evolution: Derived from CD technology but optimized for larger storage and multimedia.
Core Improvements: Smaller pits, tighter spiral, red laser, enabling higher data density.
Capacity Increase: Up to 4.7 GB for single-layer DVDs (7x a CD's capacity).

DVD Formats

Standard DVD Formats: Single-sided, single-layer: 4.7 GB
Single-sided, dual-layer: 8.5 GB
Double-sided, single-layer: 9.4 GB
Double-sided, dual-layer: 17 GB

DVD Capabilities

Multimedia Capabilities: High-resolution video (720 x 480), supporting up to 133 minutes of content with MPEG-2 compression, plus audio and subtitles in up to 8 languages, and subtitles in 32 languages.

Blu-Ray

Successor to DVD, named for its shorter wavelength blue laser.
Improved Focus: Blue laser allows for smaller pits and lands, enabling higher data density.
Storage Capacity: Single-sided Blu-Ray: 25 GB, Double-sided Blu-Ray: 50 GB.
Data Transfer Rate: ~4.5 MB/sec, higher than DVD but slower than modern magnetic disks.
Expected Replacement: Likely to phase out CD-ROMs and DVDs due to higher capacity and performance.
Adoption Timeline: Full transition expected to take several years.

Input/Output (I/O)

Computer system components = CPU, memories (primary/secondary), I/O equipment.
I/O equipment: Printers, scanners, modems.
I/O equipment connects to the rest of the system via buses.

Buses

Definition: A communication system that transfers data between components within a computer or between computers.
Motherboard Components:
CPU (Central Processing Unit): Brain of the computer, executing instructions.
DIMM (Dual In-line Memory Module) Slots: Slots for RAM modules allowing memory expansion.
Support Chips: Manage functions like memory control and interfacing.
Bus System: A pathway etched onto the motherboard connecting CPU, memory, and I/O devices.
Structure of I/O Devices:
Components (Controller): Contains most electronics for managing the I/O device (e.g., hard drive, printer, scanner).
Device Itself: The physical unit.
Function of Controllers: Translate CPU commands into actions for the I/O device.
Direct Memory Access (DMA): Allows data transfer between I/O devices and memory without CPU intervention, streamlining handling and improving efficiency.
Interrupt Mechanism: Controller sends an interrupt signal to the CPU, halting current operation; execute an interrupt handler routine to process I/O completions.
Bus Utilization: Shared resource used by CPU and I/O controllers.
Bus Arbitration: A component (bus arbiter) controls bus access ensuring orderly device access.
Priority Scheme: I/O devices receive priority to prevent data loss, especially hard drives. The CPU can use the bus exclusively when no I/O requests are present
Cycle Stealing: I/O devices request bus access, interrupting CPU processes, which can slow overall system performance.
Performance Challenges: Increasing speeds of CPUs and components have led to bus contention issues, creating bottlenecks.

Legacy and Modern Bus Technologies

Legacy Buses: ISA Bus (Industry Standard Architecture)- becoming obsolete due to limitations in speed and bandwidth, EISA Bus- enhancement of the ISA bus maintaining backward compatibility with improved performance.
Modern Bus Technologies: PC Bus (Peripheral Component Interconnect)- designed for high-speed data transfer and ease of use, widely used to connect CPU with high-bandwidth peripherals.

Terminals

Computer terminals consist of a keyboard and a monitor (often integrated in older systems).

Keyboards

Original IBM PC: Snap-action switches for tactile and audible feedback.
Cheaper Keyboards: Simple mechanical contact for key activation.
Advanced Methods: Some keyboards use magnets and coils to detect key presses.
Operation: Key press generates interrupt; handler reads register for key code; release also triggers interrupt.
Software handling: Multikey sequences (SHIFT, CTRL, ALT) processed by software for enhanced functions.

CRT Monitors

Structure: Cathode ray tube (CRT) and power supplies housed within a box.
Functionality: Electron gun emits electron beam towards phosphorescent screen, producing images via raster scanning.

CRT Raster Scanning Process

Horizontal Sweep:Electron beam sweeps horizontally across screen with a controlled voltage increase.
Vertical Sweep: Electron beam returns to the left side after completing horizontal sweep with vertical deflection plates.
Refresh Rate: The screen is repainted at 30-60 times per second.

CRT Grid Function

Grid controls electron acceleration; positive voltage allows passing (glowing screen); negative voltage repels and prevents glow.
Visual Output: Binary control converts electrical signals into displayed pixels (bright/dark spots) illustrating an image.

Flat Panel Displays

Transition from CRT to LCD: CRT monitors are too bulky for portables, leading to LCD adoption; lightweight and slimmer.
Liquid Crystal Technology: Organic molecules that flow like liquids, but have structured arrangement; allowing light manipulation based on molecular alignment.

Flat Panel LCD Structure

Basic Structure: LCD consists of two glass plates with a liquid crystal sandwiched between, transparent electrodes, and light sources to illuminate the screen. Polarizing filters (polaroids) are attached to both sides to manage light polarization

Twisted LCD Structure

Twisted Structure: TN (Twisted Nematic) display features horizontal/vertical grooves on the rear/front plates which causes liquid crystal molecules twist.

Flat Panel Display Matrix Configurations

Passive Matrix Displays: Use perpendicular wires to create a grid.
Active Matrix Displays: Incorporate TFTs (Thin Film Transistors) at each pixel, enabling independent voltage control for better image quality.

Video RAM

Purpose: Used in CRT and TFT displays for refreshing the screen.
Information for each screen image is stored in a bitmap.
Storage Requirements: For 1600x1200 resolution, requires storage for the RGB values in bytes.
Color Palette Option: Indexed color can be used to reduce memory requirements.

Video RAM (Bandwidth and AGP)

Bandwidth Challenges: High screen resolution/video playback requirements exceed older bus architectures like (E)ISA and PCI
AGP Bus Introduction: To address limitations, Intel developed AGP (Accelerated Graphics Port); for higher-speed graphics performance.

Mice

Evolution of Computer Users: Early computers were operated by experts; now minimal technical knowledge.
Why a Mouse: Early interfaces used command lines; point-and-click interfaces (Windows/Macintosh) eased navigation.
Mechanical Mouse: Features two perpendicular rubber wheels/rolling ball for tracking movement.
Optical Mouse: Uses LED and photodetector, no moving parts; tracks by sensing grid lines crossed on special pad.
Optomechanical Mouse: Combines mechanical and optical elements, using a rolling ball and light pulse encoders.
Data Transmission: Data packets for mouse movement and button states sent serially to the computer.

Printers

Matrix Printers: Technology uses print heads (7-24 needles) forming dots arranged in matrices; for efficiency on large forms, receipts, and multipart continuous forms with carbon paper.
Inkjet Printers: Technology uses piezoelectric or thermal crystals to control individual droplet sizes for various printing qualities; usually affordable.
Laser Printers: Technology utilizes a rotating drum; charged and exposed to a laser, creating light/dark spots for toner application; excellent for high-quality/fast printing, sometimes combining printing/copying/faxing functions.

Color Printers

Color Representation: Monitors use RGB; printers use CMYK
Gamut and Calibration: Devices have limited color ranges that require calibration to match screen(RGB) and printed colors (CMYK)
Inkjet Printer Types: Dye-based, pigment-based; common ink cartridges.
Solid Ink Printers: Uses melted wax ink, offers stable color over time but with long startup time

Advanced Color Printers

Color Laser Printers: Uses CMYK toners; large memory, high quality but may need time, best for lasting color
Wax Printers: Uses heated wax ribbons for vibrant color.
Dye Sublimation Printers: Vaporizes dye for near-continuous colors without halftoning; best for use for high quality photograph.

Telecommunication Equipment

Most computers connect to a network (often the Internet).
I/O equipment required for network communication

Modems

Definition: Modulates and demodulates data for transmission over phone lines.
Purpose: Connects computers over telephone lines, enabling communication between various devices,
Challenge: Raw digital signals don't transmit well; need modulation.
Digital Signal Transmission Issue: Digital signals distort.
Solution: Modulation (using carrier sine wave, 1000-2000 Hz). which carries data with minimal distortion

Modem (Modulation/Demodulation)

Modulation: Converting digital data into analog signals for transmission.
Demodulation: Converting received analog signals back into digital data to retrieve original information.
Types of Modulation: Amplitude Modulation (AM), Frequency Modulation (FM), Phase Modulation (PM).

Modem (Advanced Techniques)

Dibit Phase Encoding: Transmits 2 bits per time interval, using different phase shifts for encoding.
Baud and Bit Rate: Baud rate refers to signal changes per second; bit rate can be higher if multiple bits are sent per baud.

Modem Data Transmission

Serial Transmission: 8-bit characters sent serially over single-channel telephone lines.
Start and Stop Bits: Each character preceded by a start and followed by a stop bit, increases bit count to 10. (example given 9600baud)
Types of Data Transmission Modes:
Full-duplex: Simultaneous, two-way transmission using different frequencies.
Half-duplex: Data travels in one direction at a time.
Simplex: Data travels only in one direction.

Modem Capabilities

Data Rates: 28,800 bps to 57,600 bps with low baud rates; advanced techniques combine modulation methods for higher bit rates.

Digital Subscriber Line (DSL)

Overview: High-speed Internet access technology over traditional telephone lines.
ADSL: Asymmetric DSL, higher download speeds than upload speeds.
Broadband Concept: Offers broader bandwidth compared to earlier dial-up, often marketed as "Broadband".
Voice Optimization: Traditional phone lines designed for voice, bandwidth is limited to 3000 Hz.

Wireless Technologies

Wireless has become ubiquitous and increasingly important.
Wi-Fi: Uses radio waves for data transfer; widely used in homes and offices for high speed data access.
WiMax: A wireless broadband wireless solution that works via radio towers for longer distance communication; used today; often used by businesses or in public areas;
Mobile Networks: Wireless communication networks have become more important as mobile devices have proliferated.
Cellular Technologies: Many different cellular technologies exist today.

Digital Cameras

Overview: Peripherals that capture images electronically, mainly using a CCD sensor array.
Mechanism: Uses a lens to focus an image onto a CCD (Charge-Coupled Device) array replacing film. Analog-to-digital converter reads intensities to generate digital data.
CCD Array: Converts light into electrical charges with values from 0-255.
Color Filtering: A Bayer filter separates light into red, green, and blue components within the CCD array. Each pixel consists of four CCD sensors for full color capture
Interpolation: Software combines pixel data to create a full-color image.

Digital Cameras Image Capture Functions (Processes)

Focus: Adjusts lens based on image detail.
Exposure: Determines optimal light intensity.
White Balance: Adjusts color based on light source spectrum.
Storage: Saves data in camera's RAM (high-end SLRs may use more) for rapid frame capture

Digital Camera (Post-Capture Processing)

White Balance Correction: Adjusts colors to reflect true tones.
Noise Reduction: Reduces image noise.
Sharpening: Enhances edges to improve detail.
Compression: JPEG format compresses images, reducing filesize with potential detail loss.

Digital Cameras (Image Storage/Transfer)

Storage Media: Saved on flash memory; Micro drives.
Image Transfer: Connects to computers via USB, FireWire, etc
Editing Software: Tools exist for further editing (e.g., Adobe Photoshop).

Digital Cameras Embedded Computing

Embedded System: Modern digital cameras have powerful processors
Capabilities for managing functions: lens/flash, real-time display, controlling buttons/settings.

ASCII (American Standard Code for Information Interchange)

Character encoding standard used primarily in early computers.
Bit Length: 7 bits per character; has 128 possible characters (including control characters).
Purpose: Represents text in computers/telecommunication.
Examples: SOH, STX, ETX, EOT (used for control in data transmission)

UNICODE

Formed by companies, developed as a universal standard.
16-bit encoding assigns a unique code point for every character.
65,536 code points cover many world languages and symbols
ASCII compatibility; Latin 1 has code points 0-255, mapping to ASCII.
Code Point Allocation: Divided into blocks of 16, organized by script and helps with various language challenges.
Diacritical Marks: Each mark has it's own code point; software combines them to create new symbols
UNICODE Challenges: Script-based sorting issues; requires external tables; dynamically growing language (new words/names).
Cultural Sensitivity and Controversies: Number of code bits for some languages vary (Han ideographs) and reflects cultural inclusion in allocation.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.