Notes, summaries, assignments, exams, and problems for Computers

Understanding Computer Memory

Memory Types

Main Memory

Main memory is integrated into the system's firmware and directly governed by the CPU. It stores the boot process, data from the stack, memory-resident programs, and the user program currently executing.

Types of Main Memory:

• Ferrite memories (obsolete)
• Integrated memory:
  • RAM (Random Access Memory)
  • ROM (Read-Only Memory)
  • PROM (Programmable ROM)
  • EPROM (Erasable Programmable ROM)
  • OTP Memory (One-Time Programmable ROM)
  • EAROM (Electrically Alterable ROM)

Cache Memory

Cache memory is located within the CPU and communicates directly with it. It stores frequently used data to reduce access time from main memory.

Mass Memory

Mass memory refers to storage devices with higher capacity, typically peripherals.

Types

Client-Server Model

• The client-server model defines the structure of communicating applications and their synchronization.
• It consists of two interacting processes:
  • Server Process
  • Client Process
• Client and server are inseparable; one cannot exist without the other.

Server

• This process awaits hearing on a given server port. It continuously waits for remote client processes to connect.
• Authentication
• Security and information privacy in the system where they reside.
• Must be able to handle requests from multiple clients simultaneously.
• Important: All clients will be connected to the same server port.

In general, we say that a computer is a server when its operating system runs one or more server processes (FTP, HTTP, DNS, etc.).

Client

• It is a process that sends

Video Capture and Storage

Factors Affecting Video Capture Speed

Which of the following is not a factor in the loss of speed in video capture to your computer?

• CD/DVD speed

Recommended Hard Disk Data Transfer Rate

For video capture, the recommended minimum hard disk data transfer rate is:

• 2.5 Mb/sec
• 5.0 Mb/sec
• 4.5 Mb/sec
• 3.5 Mb/sec

Peak Writing Definition

The amount of information a hard drive can write consistently in one second is called Peak Writing.

Data Compression

Compression Process

Compression is the process of removing or restoring data to reduce the size of a file.

Synchronous vs. Asynchronous Compression

When the algorithmic compression process takes the same amount of time as the decompression process, it is called Synchronous.

Audio Formats and

Matrix Operations and Linear Equations in MATLAB

Format short, long format, format rat (format is the x / y), format short (as is 3 * 10^-5 = 3e-5). A = [; ;]. To extract a positive one: A(2,2). Changing a number in one position: A(row, column) = number in that position.

Write a whole line: A(row,:). or A(row, 2:4) - the columns you want from that row. For columns it is the same but in reverse: A(:, 3:7). Extract a submatrix A(2:3, 2:3) - ever-growing range. Transpose: A.'. Conjugate matrix (star A*): A'. Matrix for blocks: [A | E] - like n-th row or [A; E] - so I place it under.

Matrix by number unit: 23 * ones(3). Identity: eye(x, y).

Systems of Linear Equations Ax = b:

• Rank(A) = rank(A | b) = No incog. - SCD: x = A \ b
• Rank(A) = rank(A | b)

Components

DNS Client, DNS Servers, Zones of Authority

Transport Layer Model: TCP/IP

TCP

The Transmission Control Protocol (TCP) ensures reliable communication between the sender and receiver of a message.

UDP

The User Datagram Protocol (UDP) offers a lower guarantee of packet delivery compared to TCP because it doesn't use acknowledgments.

Implementation Level of the TCP/IP Model

The application layer is the level where common programs communicate over a network.

ICMP

The Internet Control Message Protocol (ICMP) is a sub-protocol for diagnostics and error reporting within the Internet Protocol (IP).

FTP

The File Transfer Protocol (FTP) is part of the TCP/IP suite and provides file transfer services.

HTTP

The HyperText Transfer Protocol (HTTP) is the foundation... Continue reading "TCP/IP Model and Comparison with OSI Model" »

Media Player Functionality

A media player can play both audio and video, including TV programs. Common widget types include:

• DVD (xine)
• Audio (Winamp)
• Video (Windows Media)
• Multimedia (Movie Player)

FLV Format

FLV is a streaming video format popular on the internet, especially due to platforms like YouTube and Google Video. It requires Adobe Flash Player.

Video Editing Process

Video editing encompasses all operations performed during movie production.

Movie Components

Key components of a movie include:

• Menu
• Movie
• Frame
• Transition
• Clip

Windows Movie Player

Windows Movie Player is a built-in Windows application for simple and comprehensive video editing.

Film Editing

Film editing involves inserting various clips in chronological order for viewing.

Mounting Process

The... Continue reading "Media Player, Video Editing, and Movie Production Essentials" »

FireWire: High-Speed Serial Bus Interface

FireWire is an interface designed to connect up to 63 devices. The bandwidth of this bus is either 400 Mbps or 800 Mbps, depending on the version. IEEE 1394a supports up to 400 Mbps, while IEEE 1394b supports up to 800 Mbps.

Computer Peripherals: Input, Output & Storage

Peripherals are a set of elements, often referred to as information media or mass storage units, that are necessary to store data and information and are available to the central processor. There are two main types:

Input Devices

An input device is any device through which information is introduced to the central processing unit (CPU).

Output Devices

An output device is any device through which information is drawn from the central processing... Continue reading "Computer Hardware Essentials: Ports, Storage & Interfaces" »

Here's a list of essential Linux commands:

• lime - Displays the current calendar.
• lime 1980 - Shows the calendar for the year 1980.
• cal 12 1980 - Displays the calendar for December 1980.
• date - Displays the current date.
• date -s "2009-11-05 18:55" - Changes the system time.
• who - Shows who is currently logged into the system.
• who -u - Displays the process ID (PID) of logged-in users.
• kill -9 3525 - Terminates the process with PID 3525.
• uname - Outputs the machine's name.
• uname -a - Shows detailed information about the machine.
• uptime - Displays how long the machine has been running.
• du - Displays disk space usage by folders.
• du -k - Displays disk space usage in 1024-byte blocks.
• df - Displays disk usage statistics.
• ps - Displays a general list of running processes.

Data Link Layer Fundamentals

1. MAC vs. LLC Sublayers: Motivation

The Data Link Layer (Layer 2) is crucial for connecting to upper layers and managing device communication within a local network. It employs specific addressing schemes to identify devices and uses frames to group bits for transmission. This layer is divided into two sublayers:

• Logical Link Control (LLC):
  • Establishes the connection with upper layers, integrating with network layer protocols.
  • Identifies the network layer protocol (e.g., IPv4, IPv6) for the encapsulated packet.
  • Remains independent of the physical equipment, providing a consistent interface to the network layer.
• Media Access Control (MAC):
  • Responsible for bringing data onto and off the physical media.
  • Handles data encapsulation,

Core Computer System Components

Hardware, Software, and Firmware Defined

Hardware is the physical part of a system. Software is a set of programs and applications consisting of instructions and routines that are used to coordinate programs and microprogrammable devices. Firmware is system software recorded in the electronic structure of a system, containing a set of programs that serve as intermediaries between software and hardware.

The Arithmetic Logic Unit (ALU)

The ALU (Arithmetic Logic Unit) is the operational part of a microprocessor. This complex combinational circuit is responsible for performing arithmetic and logic operations. ALU types include 0-address, 1-address, 2-address, and 3-address ALUs. Inside the ALU are two registers: the... Continue reading "Fundamentals of Computer Architecture and the 8086 Microprocessor" »