Info Tech 1

• Boolean Operations:

  • Boolean operations manipulate true/false values
  • Specific operations include AND, OR, XOR (exclusive or), and NOT
• Analog and Digital Computers:

  • Analog data includes sound waves that vary continuously over time
  • Digital data consists of discrete energy values represented by ones and zeros
  • Computers produce digital data in binary form
• Analog vs Digital Transmission:

  • Analog transmissions vary continuously, like broadcast TV and radio
  • Digital transmissions are made of square waves with clear beginnings and endings
• Memory Hierarchy:

  • Registers, L1 Cache, L2 Cache, Main Memory, and secondary and tertiary storage are part of the memory hierarchy
  • Main memory consists of volatile RAM, with common forms being dynamic RAM and static RAM
• Buses:

  • A bus is a collection of traces that transport information between hardware devices
  • I/O channels are shared by several devices to perform I/O operations independently of the system's main processors
• Processor:

  • Processor executes machine-language instructions and has different execution modes like User mode and Kernel mode
  • Memory protection and management prevent processes from accessing unauthorized memory
• Spooling:

  • Spooling is a buffering technique that uses an intermediate device to coordinate communications between processes and I/O devices
• Bootstrapping:

  • Bootstrapping loads initial OS components into memory and is performed by the computer's BIOS
  • If the system is not loaded, the user will be unable to access any of the computer's hardware
• High-level languages: Instructions look similar to everyday English
• High-level Languages Examples: C, C++, Java, Python, etc.
• Batch processing: executing jobs by collecting them in a single batch and executing them without further interactions from users
• Interactive processing: users have no interaction with the operator, suitable for tasks where data and processing decisions are established in advance like payroll
• Real-time processing: requires efficient coordination with user needs, actions performed by the computer in accordance with deadlines in its external real-world environment
• File manager: software component within the OS kernel that coordinates the use of mass storage, allows users to group files into directories or folders, allows hierarchical organizations of folders called subdirectories
• Device drivers: software units that communicate with controllers (peripheral devices like printers), designed for a particular type of device
• Memory manager: a component in the OS kernel that coordinates the use of main memory, finds and allocates memory space for each program, keeps track of memory areas that are no longer occupied, makes use of virtual memory when program requirements exceed available memory
• Protocol standards define the syntax of the data transmitted and all other rules that govern communications
• Network Classification by Size:

  • Local Area Network (LAN): covers a limited geographical area
  • Personal Area Network (PAN): connects mobile phones, personal computers, and peripherals close to one person
  • Wide Area Network (WAN): covers a country, continent, or the whole world
  • Metropolitan Area Network (MAN): covers a campus or a city
• Network Topologies:

  • Bus Network
  • Ring Network
  • Star Network
  • Tree Networks
  • Meshed Networks
  • Star-bus Networks
• Symmetric & Asymmetric Protocols:

  • Symmetric: implementations at both ends of the communications channel are identical
  • Asymmetric: implementations at both ends are slightly different
• Standard & Proprietary Protocols:

  • Standard: controlled by official standard bodies
  • Proprietary: controlled by commercial organizations
• Standard & Proprietary:

  • Standard protocols are controlled by official standard bodies like ISO, ANSI, ITU, EIA
  • Proprietary protocols are controlled by commercial organizations and lock users to specific suppliers
• Data Compression:

  • Sometimes segmentations are too large for transmission and packets can be compressed to become smaller
  • Data compression makes transmission more efficient, especially for images, long videos, and audios with redundant information
• Quantitative Characteristics:

  • Bandwidth, Capacity, Throughput, Utilization, Noise, Delay, Jitter can be measured in networking
• Bandwidth:

  • Range of frequencies effectively carried by the channel, measured in Hertz (Hz)
• Capacity:

  • Data rate or speed, measuring the number of bits carried by the channel in one second, measured in bit/s
• Throughput:

  • Number of bits carried by the channel in one second as experienced by an end user, measured in bit/s
• Utilization:

  • Proportion of time that the channel is fully occupied, measured in %
• Noise:

  • Measured by comparing its power with that of the signal in deciBel (dB)
• Delay:

  • Measures the time a signal enters the channel at the transmitter to the time it exits at the receiver, measured in milliseconds (ms)
• Jitter:

  • Variability of delay, important for real-time applications, measured in standard deviation
• Protocol standards define syntax of the data transmitted and all other rules that govern communications
• Protocol header contains information relevant to the peer layer
• Network Ownership Classification:

  • Open network: internal operation based on design that are in public domain
  • Closed/proprietary network: controlled by a particular entity, applications are restricted by license fees and contract conditions
• Network Classification by Size:

  • Local Area Network (LAN): covers a limited geographical area
  • Personal Area Network (PAN): connects mobile phones, personal computers, and peripherals close to one person
  • Wide Area Network (WAN): covers a country, continent, or the whole world
  • Metropolitan Area Network (MAN): covers a campus or a city
• Network Topologies:

  • Bus Network
  • Ring Network
  • Star Network
  • Tree Networks
  • Meshed Networks
  • Star-bus Networks
• Quantitative Characteristics:

  • Bandwidth, Capacity, Throughput, Utilisation, Noise, Delay, Jitter can be measured in networking
• Bandwidth:

  • Range of frequencies effectively carried by the channel, measured in Hertz (Hz)
• Capacity:

  • Also known as data rate or speed, measures the number of bits that can be carried by the channel in one second, measured in bit/s
• Throughput:

  • Number of bits that can be carried by the channel in one second as experienced by an end user, measured in bit/s