Notes, abstracts, papers, exams and problems of Computers

Program Counter (PC) and Instruction Register (IR)

The Program Counter (PC) contains the address of the instruction to be read. The Instruction Register (IR) contains the last statement read.

Interrupts

Interrupts interrupt the normal execution of the processor. They appear mainly as a way to improve processing efficiency. Interrupts can be generated by software, clock, I/O, or hardware failure.

Disabled Interrupts

Disabled interrupts mean that the processor will ignore the interrupt signal. If an interruption occurs during that time, it generally will remain pending and will be checked by the processor after it enables interrupts.

Processor Actions

When the processor interprets the instruction and performs the action, the action can be classified... Continue reading "CPU Operations: Interrupts, I/O, DMA, and Multiprogramming" »

Computer System Components and Definitions

Perform = realizar || Word processor = procesador de textos || Built-in = incorporado || Store = tienda || Financial = financiero

Keep, save = mantener, guardar || Execute, do = ejecutar, hacer || Monetary = monetario || Connected to the internet = conectado a internet || Program used for text manipulation = programa para manipular texto || Copy files from a server to your PC or mobile = copiar archivos de un servidor a PC o móvil

Perform operations = realizar operaciones || Do research = hacer la investigación || Carry out transactions = llevar a cabo transacciones

Monitor = monitor || Keyboard = teclado || Printer = impresora || Scanner = escáner || Speakers = altavoces || Fan = ventilador || Processor

Semaphores: Synchronization Tool

Semaphores are a synchronization tool designed to solve critical section and synchronization problems. A semaphore is an integer variable accessed only through two atomic operations: Wait and Signal. When a process modifies the semaphore's value, no other process can simultaneously modify that same semaphore value. The semaphore is initialized to a non-negative value.

Wait and Signal Operations

• Wait (P): Decrements the semaphore's value. If the value becomes negative, the process is blocked.
• Signal (V): Increments the semaphore's value. If the value is not positive, a blocked process waiting on this semaphore is unblocked.

The definitions are:

P(s):

while (s <= 0)
s--;

V(s):

s++;

Operating System Usage

Operating... Continue reading "Semaphores for Synchronization in Operating Systems" »

Secure Sockets Layer (SSL)

Secure Sockets Layer (SSL) is most often used to encrypt information on the Internet. It is a protocol that encrypts database (DB) connections by selecting an encryption method and generating the necessary keys for the entire session.

How SSL Works

1. The browser requests a page from a secure server. The request is identified by the HTTPS protocol.
2. They agree on algorithms that ensure confidentiality, integrity, and authenticity.
3. The server sends the browser its standard X509 certificate containing its public key. If the application requires it, it in turn requests the client's certificate.
4. The browser sends the server a master key from which it generates the session key to encrypt data to be exchanged.
5. Finally, it checks the

Models of Network Integration

Typically, a network encompasses a wide range of technologies. Not all technologies meet all the needs of the network administrator. A network of a certain size is usually a mixed-technology network due to the various factors involved.

Key Aspects of Network Integration:

• Wiring System Response: The wired network forms the backbone of any Local Area Network (LAN). Typically, all servers have at least one connection to the wiring harness, and if they handle substantial traffic, the connection is high-speed. Clients can connect to services through a structured cabling network or wireless connections. Note that the bandwidth of a wireless access point is generally less than that of wired Ethernet access and is shared

Workshop Planning and Control

Planning

Planning aims to coordinate workload with available resources and equipment to perform the required services in production, or the quantity and quality required, at the lowest cost and meeting the deadline.

Organization

Methods, order, time > budget OR > acceptance > delivery term.

Workload

The workload is the amount of work available for the workshop, consisting of the OR already issued and accepted by clients.

Production Capacity

Production capacity is the amount of work that the workshop can perform based on available operators, equipment, and facilities.

The workload can be defined in a working or time to implement and scale, or are uncertain about working with an open OR work involving a diagnostic... Continue reading "Workshop Workload and Production Capacity Management" »

Fuzzy Logic

Fuzzy logic extends Boolean logic, allowing intermediate values between TRUE (1) and FALSE (0), such as MAYBE (0.5). A fuzzy logic value can be any value within the range of 0 to 1. This logic incorporates statistical concepts, especially in inference. Fuzzy logic implementations enable control devices to handle indeterminate states, allowing for the evaluation of non-quantifiable concepts. Practical examples include evaluating temperature (hot, warm, medium), happiness (bright, happy, apathetic, sad), and the veracity of an argument (absolutely right, right, counter-argumentative, inconsistent, false, totally wrong).

Fuzzy logic is a research area focused on uncertainty treatment and a family of mathematical models dedicated to... Continue reading "Understanding Fuzzy Logic and Backpropagation in Neural Networks" »

1) Entering Configuration Screen

To enter the configuration screen from runtime mode:

• It depends on the configuration of the last application downloaded.

2) Dip Switch Settings

According to the dip switch settings shown in the figure:

• Starting from the CF card is disabled, you can download, and forced closure is disabled.

3) Screen Ventilation

To facilitate the ventilation of the screen, the manufacturer recommends a minimum distance of 100mm from any adjoining structure or equipment.

4) XBT-G LED Indicator

If the LED on the right side of the XBT-G screen lights orange, this means:

• Backlight is off.

5) COM1 Connector (SUB D25)

The female SUB D25 connector, COM1, of the XBT-G screen is used for:

• Serial communication with the PLC.

6) XBT-G Back Protection

The

The Graphics Card

1. What are Graphics Cards?

A graphics card is the hardware component of a computer that generates the image displayed on the monitor. The graphics card has evolved from a mere interface between the microprocessor and the display, which simply translated information consisting of an 80x24 character screen into an analog signal compatible with the monitor, to managing images with resolutions of 1024x768 pixels or more, with millions of possible colors and refresh rates over 70 Hz.

Current graphics cards have their own dedicated CPU for graphics operations and their own RAM, whose capacity is approaching and may even exceed that of the system.

2. Components of a Graphics Card

A graphics card has three main components:

• The graphics