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

Supercomputer

Supercomputers are the fastest type of computer available, used for complex calculations in specialized fields like weather forecasting. Their high cost limits their use to specific applications.

Mainframe

Mainframes were originally large cabinets housing central processing units. With the advent of smaller computers, the term evolved to describe powerful machines capable of handling large-scale operations and supporting numerous users simultaneously.

Minicomputer

Minicomputers are mid-sized systems that bridge the gap between mainframes and workstations. They can support multiple users and offer processing power suitable for various tasks.

Personal Computer (PC)

Personal computers are small, affordable computers designed for individual... Continue reading "Computer Types: From Supercomputers to Personal PCs" »

What is Cloud Computing?

Cloud computing is the delivery of computing services over the internet to offer faster innovation, flexible resources, and economies of scale.

Top Benefits of Cloud Computing

• Cost: Eliminates the capital expense of buying hardware and software and setting up and running on-site data centers.
• Speed: Most cloud computing services are provided self-service and on-demand, so even huge amounts of computing resources can be provisioned in minutes.
• Global Scale: Offers the ability to scale elastically.
• Productivity: Cloud computing removes the need for many tasks, so IT teams can spend time achieving more important business goals.
• Performance: Reduces network latency for applications and provides greater economies of scale.
• Security:

VoIP and Networking Core Concepts

1. What is an IP-Based PBX?

What is the PBX where all switching is done in IP?

1. IP Enabled PBX
2. Hybrid PBX
3. IP-PBX
4. TDM-PBX

2. Firewalls for IPv6 VoIP Connections

What kind of firewalls are designed to manage VoIP connections in IPv6?

1. Traditional firewalls
2. SIP Application Level Gateways
3. Session Border Controller
4. Jitter Buffer

3. VoIP vs. PSTN: Disadvantages

What is NOT a VoIP advantage over PSTN telephony?

1. Access from anywhere, not constrained to a physical location
2. Security, Resiliency, and Availability
3. It depends on electricity
4. Video conferencing possibilities

4. Asterisk Dialplan Variable Types

Which of the following are NOT variables we can use in Asterisk dialplans?

1. Channel variables
2. Environment variables
3. Global variables
4. Local variables

5.

1. Non-Volatile Memory

Non-volatile memory retains stored information even when not powered. It is used for secondary storage or long-term persistent storage. Examples include:

• CD
• Hard Disk (similar reading and writing time)
• Solid-State Drive (SSD): No moving mechanical components, no difference for sequential vs. random reading, but a significant difference between reading and writing.
• ROM
• Flash Memory
• Magnetic Tape: Natural sequential reading and writing, suitable for backups.

2. File System

A file is a contiguous logical address space that can be written to, read from, opened, closed, and deleted. It has the following attributes:

• Name
• Unique ID
• Type
• Location
• Size
• Protection
• Date

Information about files is stored in file system structures.

3. Directory

A directory... Continue reading "File Systems: Structure, Management, and Optimization" »

Technology: Creating Practical Solutions

Technology is creating practical solutions to satisfy human needs and problems.

Factors in the Technological Process

Physical and scientific concepts

Technical drawing

Materials and their properties

Work techniques

Economic factors

Information technology

Stages of the Technological Process

Needs and problems

Collecting information

Designing (drawing)

Planning (materials-tools-time-money-people in charge)

Building

Evaluating and checking

Writing a report

Materials for technical use

Resolution and Sensitivity

Resolution = MaxV / (2^bit - 1).

Linear Potentiometer

Total Resistance = 800 Ohms, E = 2V, L = 10 cm.

Sensitivity = V/L. Max/Min Z.

Z_out = || 80{10 - |x|}.

Z_min = 0 Ohms.

Z_max = 400 || 400 = 200 Ohms.

Unknown input impedance = voltage follower.

Gauge Factor

20mm wire strain gauge resistance = 150 Ohms. Under force tension, R changes by 5, and L changes to 0.08.

Load Cell

Load Cell Sensitivity / Minimum Value of N.

LC makes a change in V from 0 to 2V. V varies linearly.

LCS = 2V / 10N = 0.2 V/N.

Minimum Value of N = 10N / 0.1N = 100, 2⁶.

Filters

IIR Filter Identification

Unbounded, non-causal.

IIR/Unbounded. y[n-1] = 200x[n] + 300x[n-1] - 500x[n-2]. Non-causal.

Digital-to-Analog Conversion

N-bit R-2R Ladder

V = 0/6.4. n = 5.

Maximum V_out... Continue reading "Understanding Sensors, Filters, and Data Conversion" »

Solid Bulk Terminals

As the name implies, solid bulk terminals handle bulk cargo and are typically located near port entrances.

Design

These terminals don't require a continuous berth. The current trend is to construct them with a light working platform.

Goods

Solid bulk terminals handle various goods, categorized as follows:

• Primary Bulk Cargo: Iron ore, cereals, coal, bauxite, and phosphates.
• Secondary Bulk Cargo: Metals, minerals for construction (coke, cast iron, cement, magnesium ore, scrap), and other agricultural products.

Storage

Storage methods depend on the cargo type:

• Clean Bulk: Products for human or animal consumption (cereals, flour, animal feed) require specific handling and storage facilities.
• Dirty Bulk: Materials from mining and steel

Teen Room Essentials

Furniture

• Chest of drawers: A piece of furniture with drawers in which you keep things such as clothes.
• Cushion: A bag made of cloth, plastic, or leather that is filled with soft material, often has an attractive cover, and is used especially on chairs for sitting or leaning on.
• Duvet: A quilt, often with a removable cover; comforter.
• Wardrobe: A tall cupboard in which you hang your clothes.

Room Atmosphere

• Dimly-lit: Describing the way a room is lit when there's only a small amount of light.
• Restful: Used to describe something that produces a feeling of being calm and relaxed.

Social Dynamics

• Alter: To change, or to make someone or something change.
• Compromise: The act of agreeing to something that is not exactly what you want in

Properties of Metals

PROPERTIES OF METALS: good electrical, thermal and acoustic conductors; ductile and malleable; tough; they melt at high temperatures, expand when the temperature rises and contract when it cools; some are magnetic; rust when they come into contact with air and oxygen (not all); can be recycled and reused, some are toxic for the environment.

Ferrous Metals

FERROUS METALS: main component is iron.

PURE IRON: greyish white colour, good magnetic properties. Disadvantages: only melts at high temperature, difficult to machine, fragile and brittle. Uses: rarely used, used in electronics and electrical components. CAST IRON: very hard and resistant. Uses: machine parts, casing for engines, stands for machines, pistons, street lamps,... Continue reading "Properties of Metals and Ferrous vs. Non-Ferrous Metals" »

Function Definition

A function definition in C++ consists of the statements that constitute a function. It includes:

• Name: The identifier of the function.
• Parameter List: Variables enclosed in parentheses that hold values passed to the function.
• Body: Statements within curly braces that perform the function's task.
• Return Type: The data type of the value the function returns (e.g., int, double, void if no value is returned).

Function Header

The function header declares the function. It consists of:

• Return Type
• Name
• Parameter List

For example: void evenOrOdd(int num). Note that there is no semicolon at the end of the header.

Function Return Type

• If a function returns a value, the return type must be specified (e.g., int main()).
• If a function doesn't return