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
Relational Database Concepts and SQL Queries
Relational Algebra
Selection (σ): Horizontal tuples
Projection (π): Vertical tuples
Union Compatible: Same number of attributes, same domain, only unique tuples returned
- Union (∪): “or”, all
- Intersection (∩): “and”, similar
- Difference (-): “not”
Inner Joins
- Equijoin: Attribute used to join is repeated
- Natural Join: Gets rid of repeated attribute. Tuples without a matching attribute or null value are eliminated from the join result
Outer Joins
- Left Outer Join (LOJ): Keeps every tuple in the first or left
Database Approach vs. Traditional File System
Advantages of the Database Approach
Data Redundancy Control
- The database approach minimizes data redundancy by integrating data into a single database, which can be accessed by multiple users and applications. This reduces the risk of data anomalies and inconsistencies.
Concurrent Access and Transaction Management
- Databases support concurrent access, allowing multiple users to access and modify data simultaneously without causing data inconsistency.
- Transaction management ensures that all database operations