Notes, summaries, assignments, exams, and exercises for Computer science for Vocational training

Input/Output (I/O) Units

I/O units connect the system to the outside world, enabling the introduction and extraction of information. These units typically consist of registers operated by control buses, storing address information from the data bus. Their outputs are externally accessible for connecting to various devices.

Another crucial function of I/O units is to adapt:

• The format of signals from outside to the format of internal signals.
• Working speeds.
• Voltage levels.
• Binary codes.

System Buses

All elements of a programmable microsystem are interconnected by information channels, commonly known as buses. These buses are composed of multiple lines, each designed to transmit information of a specific type. The number of lines forming a bus determines...

Essential Database Field Properties

• Validation Rule and Validation Text: This is a standard that all data in a field must meet. If data is entered that does not meet this standard, the tables will not be updated correctly. The Validation Text is the message that appears on the screen when you enter a figure that does not meet the validation rule; this message reports the specific error being committed.
• Required: This option lets you choose whether the field will be mandatory. If you select "Yes," you cannot leave this field blank, and the table is blocked until it is filled.
• Input Mask: This sets the default format that the data will take automatically. We use 0 for numbers and L for letters. Example: 91 881 14 000 00 00 79/00
• Indexed: This lets

Key Computer and Software Terms

1. Text Editor: It is a program through which we can enter text without a specific file format.

2. Word Processing: It serves not only to write, but also to format the text and offer a better appearance.

3. Document: A data file with a specific format that is interpreted by the processor.

4. Book: An entire document with all its pages.

5. Section: An organizational unit of the document that may implement a number of characteristics.

6. Paragraph: An organizational unit below a section.

7. Style: A way of sorting, identifying, and storing a set of formatting and other features.

8. Index: A part of the document, usually found at the end.

9. Table of Contents: An index with page layout format which summarizes the contents...

Database Management System (DBMS) Functions

A DBMS is a set of programs that provide access to data. Its primary functions include:

Core DBMS Capabilities

1. Facilitate Data Access: Enables easy access to data, including graphical representations.
2. Data Consistency and Integrity:
   • Consistency: Ensures any change respects the database integrity rules.
   • Integrity: Enforces restrictions (e.g., Laboral Age > 16).
   • Registration: Prevents duplicate entries (e.g., student not repeated).
   • Table Constraints: Limits on table size (e.g., N students per group < 35).
   • Relationships: Ensures referential integrity (e.g., a producer must have a valid vendor code existing in the suppliers table).
3. Database Security:
   • Making and retrieving Backups.
   • Reaction to system failures.

Technical Design of Systems

At the end of this activity, the following items are obtained:

• Modular design of the system.
• Description of interfaces between system modules.
• Description of interfaces to other system modules.
• Definition of the user interface.
• Description of system components.

Structured Programming Techniques

Data Entry:

This part of the program consists of instructions that take information from an input/output device and transfer it to main memory for further processing.

Process or Algorithm:

The set of instructions that process the input data to obtain new information.

Output Results:

This consists of instructions that send the results of a process to an input/output device.

System Technology Environment: Objectives

The objectives include:...

What is Mathematical Logical Thinking?

These are the skills students develop associated with logical and mathematical concepts, reasoning, comprehension, and exploration of the world through real proportions, thus strengthening more abstract aspects of thought.

Geometry with Dinosaurs

This activity involves cutting out various geometric shapes with EVA rubber. Children will then create their own dinosaurs using these shapes. Through this activity, they can learn geometric shapes, count the number of elements used in each dinosaur (like the sides of the shapes), and create new geometric shapes from the ones they already have.

Logical Reasoning with Chupa Chups

This activity consists of creating logically structured material and playing with it using...

Repeaters

Repeaters: are network elements that regenerate the electrical signal that arrives in order to restore it to its original level, thus avoiding problems that might occur due to excessive attenuation. They operate at the physical layer of the OSI model, since they work with signals.

Hubs

A hub has the advantage of simply copying bits from other network segments. It requires no special configuration, being based on the physical layer. It serves no network addresses, protocols, services, etc. It simply repeats the signal from the network at high speed. It does not isolate the traffic problems generated by the network in each of the segments.

Bridges

Bridges: provide some capacity or element of control. They can accept and forward the frames...

Windows Local Area Network (LAN) Fundamentals

This document focuses on setting up a Local Area Network (LAN) environment using Windows operating systems. The hardware requirements for a basic network are straightforward.

Hardware Requirements for Windows Networking

Each computer must have one or more network adapters, typically a maximum of four. Additionally, the necessary wiring and components are required to facilitate communication between them.

Essential Network Integration Considerations

To successfully integrate a computer onto the network, several critical considerations must be addressed:

• The name of each computer on the same physical network must be unique.
• The IP address of each computer within the same physical network must be unique.
• The

OSI Model Essentials

The OSI model, developed by ISO, standardizes protocols dominated by TCP/IP and is crucial for network designers. It comprises seven layers for sending commands:

Application Layer

Provides user access to the OSI environment and distributed information services.

Presentation Layer

Ensures application processes are independent of data representation differences.

Session Layer

Manages communication between applications, establishing, managing, and closing connections.

Transport Layer

Ensures secure, transparent data transfer between points, including error recovery and flow control.

Network Layer

Manages switching and transmission techniques, establishing, maintaining, and closing connections at the hardware level.

Data Link Layer

Provides...

Process Management and Execution

Process: A program in execution.

Thread (Strand): The point of execution within a process.

States of a Process

Processes can exist in the following states: Running, Ready (standby or active), or Blocked.

Process Transitions

• Transition A: Running this program requires some element or signal to continue to run.
• Transition B: The program has used the CPU time allocated for its implementation and must make way for the next process.
• Transition C: This preparation process enters the implementation (execution) phase.
• Transition D: A blocked process transitions to the ready state.

CPU Scheduling Algorithms

• Round-Robin (Wheel Algorithm): Assigns relative execution times for different processes.
• FCFS Algorithm: Resources are allocated