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

Core SAP ABAP Concepts and Definitions

What is the Use of ALV (ABAP List Viewer)?

ALV (ABAP List Viewer) is a powerful tool in SAP that facilitates the creation and display of reports with enhanced functionalities and features. It is widely used in SAP to present data in a structured and user-friendly manner. ALV is part of the SAP GUI and is used to generate reports and tables that provide users with various options for interacting with data.

Understanding the SAP ABAP 3-Tier Architecture

The SAP R/3 architecture is a multi-tiered structure that comprises three main layers:

1. The Presentation Layer: This is the topmost tier, responsible for providing user interfaces for interacting with the system. It serves as the gateway for users to access and

... Continue reading "Essential SAP ABAP Interview Questions and Core Concepts" »

Hot and Cold Working Processes

Hot Working: This involves deforming a metal above its recrystallization temperature. The metal recrystallizes during the process, so it does not get harder or brittle while being worked.

Cold Working: This involves deforming a metal below its recrystallization temperature. This causes "strain hardening," making the metal stronger but also more brittle.

Metal Extrusion and Its Benefits

Extrusion can produce complex cross-sections that are impossible with rolling. It offers high material utilization (very little waste) and good mechanical properties, especially in cold extrusion. This process works for both brittle and ductile materials.

Common Applications of Extrusion

• Aluminum: Window frames, sliding door tracks, and

... Continue reading "Metalworking Processes and Sheet Metal Fabrication" »

Memory Hierarchy: Faster, Smaller, Costlier

The computer memory hierarchy organizes storage based on speed, size, and cost, moving from the fastest (CPU internal) to the slowest (external storage):

• Registers: CPU internal (Fastest, Smallest)
• Cache: L1, L2, L3 (Fast)
• Main Memory: RAM (DRAM)
• Secondary Storage: HDD, SSD
• Tertiary Storage: Optical, Tape (Slowest, Largest)

What Is Cache Memory?

Cache memory is a small, high-speed memory located close to the CPU. It stores frequently accessed data and instructions so the processor doesn’t have to fetch them repeatedly from slower main memory (RAM).

Cache significantly reduces memory access time, thereby improving overall system performance.

Why Cache Outperforms Main Memory (RAM)

Cache memory achieves superior... Continue reading "CPU Memory Hierarchy and Cache Mapping Techniques" »

The Internet: A Global Network

The Internet is a global network of interconnected computer networks, linking billions of devices worldwide using TCP/IP. It comprises millions of networks, including private, public, academic, business, and government, and provides extensive information resources.

The History of the Internet

The Internet, originating from ARPANet, an experimental network created in the 1960s by the US military, was launched online in 1969 under a contract by ARPA, connecting four US universities. The history of the Internet reflects the continuous growth of this network, connecting millions of people, businesses, governments, schools, and universities.

The ARPANet

The ARPAnet, created in 1969, began with four computers connecting.... Continue reading "The Internet: A Comprehensive Overview" »

ELECTRICAL INSTALLATIONS:
The electricity used to meet our energy needs (housing, buildings and industries) But there are serious dangers such as fires and electrocucions if facilities do not meet the appropriate security.
Low Voltage Electrotechnical Regulations (REBT) technical conditions and guarantees must be met by electrical installations connected to a low voltage supply in order to:
-Preserve the safety of persons and property.
-Ensure the normal operation of these facilities and prevent disruptions that could cause other facilities and prevent disruptions that could cause other facilities and services.
-Contribute to the technical reliability and efficiency of economic facilities.
Complementary technical instructions (ITC - BT)... Continue reading "Domestic Electrical Installations" »

Cloud Computing Essentials

What is a Distributed File System (DFS)?

A distributed file system (DFS) in cloud computing manages data across multiple servers for scalability, fault tolerance, and efficient access. It replicates data for high availability, balances loads, ensures data consistency, and can be cost-effective.

Examples include Hadoop Distributed File System (HDFS), Google File System (GFS), Amazon Elastic File System (EFS), and Azure Blob Storage. DFS is essential for handling large-scale data storage and processing in cloud environments.

HDFS Architecture

HDFS: Hadoop Distributed File System. Google published its paper GFS and on the basis of that HDFS was developed.

It states that the files will be broken into blocks and stored in nodes... Continue reading "Cloud Computing Essentials: DFS, HDFS, Security, and Virtualization" »

Windows Server 2016 Disk Storage Types: Basic vs. Dynamic

Windows Server 2016 supports two essential disk storage types: basic disks and dynamic disks. They differ significantly in how they manage partitions and volumes:

• Basic Disks: Use traditional disk management techniques and contain primary partitions, extended partitions, and logical drives.
• Dynamic Disks: Do not use traditional partitioning. Dynamic disks offer greater flexibility than basic disks, providing virtually no restriction on the number of volumes that can be created on a single disk.

Purpose and Function of a Subnet Mask

A subnet mask is a crucial component in networking used to divide an IP address into two distinct parts: the network portion and the host portion. Its primary... Continue reading "Windows Server 2016 Fundamentals: Storage, Networking, and Security" »

Terminal and Log Command Examples

grep -i system /etc/passwd
grep -i ubuntu /etc/passwd
grep -i '*ubuntu*' /etc/passwd
grep -i "sync$" /etc/passwd
grep -E 'info|warn' /var/log/*log* && history | tail -n 2
Windows
findstr "*error*" C:\Windows\Logs\CBS\CBS.log
Select-String -Path "C:\Windows\Logs\dism\dism.log" -Pattern "2024-04 Manager"
findstr "^2024-01 | Manager" C:\Windows\Logs\DISM\dism.log
findstr /S /I /N "failed" C:\Windows\Logs\*.log
Get-EventLog -List
Get-EventLog -LogName System -Newest 25 | Format-List
wevtutil qe System /c:200 /rd:true /f:text | findstr /i "kernel"
wevtutil qe System /q:"*[System[TimeCreated[@SystemTime>='2023-09-01T00:00:00.000Z']]]" /f:text | findstr /i /c:"ProviderName: Disk"

Disk and Mount Commands

fdisk

... Continue reading "Essential Linux and Windows Log Commands for Troubleshooting" »

Mastering Microsoft Access Field Creation

Methods for Creating Fields in Access

There are two primary ways to create a field in Microsoft Access:

1. Adding fields using a predefined template.
2. Using an existing field copied from another table.

Access Field Templates Collection

Access includes a collection of field templates designed to significantly reduce the time required when setting up new fields.

Understanding Multi-Valued Fields in Access 2007

Multi-valued fields are suitable for specific scenarios, particularly when using Office Access 2007 to interact with information stored in Microsoft Windows SharePoint Services.

Defining Field Properties in Datasheet View

Field properties can be defined in the Datasheet View. Follow these steps:

1. Open the table

... Continue reading "Mastering Microsoft Access Field Creation and Data Types" »

#useradd nombredeusuario :: para crear usuarios

#passwd :: nombredelusuario

#groupadd :: nombredelgrupo :: (forma normal)

#groupadd -g 600 nombredelgrupo :: (guid sobre 650)

#userdel nombredelusuario :: para deletear usuarios

#groupdelnombredelgrupo :: borrar el grupo

#usermod -G nombredelgrupo nombredeusuario :: para asignar usuario a grupo.

opcion 2: editar archivo /etc/group -> grupo:x:600:usuarioqueseagregara

#nano /etc/shadow :: para poder ver los usuarios y poder bloquearlos

#passwd -l nombredeusuario :: para bloquear usuario

#passwd -u nombredeusuario :: para desbloquear usuario

#sudo passwd :: para cambiar la contraseña de root

# tail /etc/passwd :: paraver informacion de usuarios

#su nombredelotrousuario :: para iniciar sesion como el usuario... Continue reading "Centos 5.5" »