Database Models: Hierarchical and Network Structures
Logical Design in Database Management
The goal of logical design is to translate the conceptual design, which represents the requirements, into a logical design that can be implemented on a Database Management System (DBMS).
There are several representations for the logical model of a database, including:
- Hierarchical model
- Network model
- Relational model
- Object-oriented model
Hierarchical Models
Hierarchical models and the concept of databases were developed between 1960 and 1970. An example of a hierarchical
Read MoreMultimedia Systems: Components and Formats
Multimedia Systems
A multimedia environment combines content represented as images, sounds, and text. A multimedia system is a computer system that supports multimedia environments. An interactive multimedia system allows users to actively participate and alter the content through their interactions. Multimedia devices are hardware components that capture multimedia information, whether audio, video, or text.
Sound Cards
A sound card processes audio signals within a computer. It is divided into:
- Digital
Understanding Computer Memory: RAM and ROM Explained
Item 4.3: Memory
Content:
- Memory
- Technical Specifications
- Types of Memories
- Random Access Memory
- Technological Characteristics
- Static RAM
- Dynamic RAM
- Types of Dynamic RAM
- Memory RAM Dynamic Classification as Physical Form
- Performance of Random Access Memory
- Read Only Memory
Memory
The term “memory” applies to any electronic component capable of storing data temporarily. There are two main categories of memories:
- Internal memory that stores data temporarily while programs are running. Internal memory uses micro-
Key Concepts in Operating Systems and Process Management
Operating System Functionalities
Operating System (OS) functionalities:
- Booting
- Data Security
- Disk Management
- Process Management
- Device Controlling
Scheduling Techniques
Scheduling techniques:
- First-In, First-Out (FIFO)
- Earliest Deadline First (EDF)
- Shortest Job First (SJF)
Scheduling Criteria
Scheduling criteria:
- Maximizing CPU utilization: The idea is to maximize the time we have processes in the RUNNING state. The goal is to execute processes efficiently.
- Maximizing throughput: The idea is to have the maximum
Data Types, Operators, and Control Structures in Programming
Data in Programming: Constants and Variables
Data can behave in two different ways in a program:
- Constants: Their value never changes during the execution of the program.
- Variables: Their value varies as often as necessary.
Naming Conventions
When naming a variable or constant, keep in mind:
- You can use any alphanumeric character, but it must always begin with a letter.
- Spaces are not allowed; use the underscore character for compound names (e.g.,
my_variable). - Name length may not exceed 32 characters.
- Do
Understanding 74193 4-Bit Binary Counter Operations
Understanding the 74193 4-Bit Binary Counter
Presetting the Counter
The flip-flops (FFs) within the 74193 counter can be preset to the logical levels present at the parallel data inputs (P3 to P0) by momentarily setting the parallel load input (PL) to LOW. This is an asynchronous preset operation, meaning it overrides the counting process. However, PL will not function if the master reset input (MR) is in its active HIGH state.
Checking the Count
The current count is always available at the outputs