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Cloud Systems vs. On-Premise Systems

• Cloud systems store data and software on remote servers in data centers.
• On-Premise systems store data and software on local, owned servers.

Cloud Systems (Online Storage & Services)

• Accessibility from anywhere with an internet connection.
• Service provider handles updates, security, and maintenance, for example Google, Microsoft, or Amazon.
• Often involves a monthly or yearly fee.
• Easy to scale storage and power as needed.
• Requires a reliable internet connection.
• Security relies on the service provider's policies.

On-Premise Systems (Local Storage & Private Servers)

• No internet required for data access on the same network.
• You are responsible for server maintenance and security.
• Higher upfront costs for hardware and setup.
• More customizable than cloud solutions.
• Scaling can be expensive and time-consuming.
• Requires technical knowledge, you must fix server failures.

Cloud vs On-Premise Analogy

• Cloud is like renting an apartment: someone else maintains the building, you pay monthly, and can move easily.
• On-Premise is like owning a house: you control everything, but you have to maintain it and upgrades cost money.

Client OS vs. Server OS

• Client Operating Systems (Client OS) and Server Operating Systems (Server OS) serve different purposes.

Fundamental Differences Between Client OS and Server OS

Client OS

• Designed for everyday use by individuals.
• Optimized for user-friendly, single-user tasks like web browsing and gaming. Supports a single or few users.
• Uses standard hardware for personal computers.
• Can connect to networks but is not designed to manage them.
• Basic security features include firewalls and antivirus.
• Software compatibility includes, supporting desktop applications like browsers and games.
• May require frequent reboots for updates.
• Usually cheaper with one-time purchase or subscription-based licensing (e.g., Windows 10/11).

Server OS

• Designed to manage network resources and multiple users.
• Optimized for handling multiple simultaneous connections, services, and background processes. Supports multiple users and permissions.
• Uses high-end hardware, more RAM, multiple CPUs, RAID storage.
• Manages and controls networks, including file sharing, databases, and web hosting.
• Advanced security features include Active Directory, role-based access, encryption, logging.
• Designed for continuous operation (99.99% uptime).
• Software compatibility includes, server-specific software like web servers, databases, and virtualization.
• More expensive, often licensed per user or core (e.g., Windows Server, Linux distributions).

Key Server OS Features for Handling Multiple Simultaneous Connections & Services

• Multi-User Support: Manages multiple users and remote connections efficiently.
• Advanced Security: Role-based access control (RBAC), encryption, firewalls, and auditing tools are included.
• Virtualization Support: Runs multiple virtual machines (VMs) to host different services.
• Load Balancing: Distributes network traffic evenly to prevent overload.
• Redundancy & Failover Support: Ensures services stay online even if hardware fails.
• High Performance Networking: Handles multiple simultaneous connections using optimized protocols.
• Centralized Management: Provides tools like Active Directory, group policies, and remote administration.
• Optimized for Background Services: Prioritizes running web servers, databases, and cloud services over user-facing apps.
• Scalability: Easily expands to handle increased demand with clustering and resource allocation.
• Automated Updates & Patching: Schedules updates without downtime or user interruption.

Example Questions and Important Points

• Commenting conventions for code.
• MariaDB review
• IF vs FOR loops
• Database design and time estimation
• Image resolution calculating
• Converting formulas
• Current software inability to fully utilize a Mac's GPU.
• Creating secure classes in PHP and Object-oriented programming in PHP.
• Search algorithm
• Data base of 2,000 entries, which algorithm and why?
• HTTPS and SSL certificates, what are they
• Oracle, what is it
• Proprietary software is closed-source software
• Entity-Relationship diagrams
• The difference between instantiation and cardinality.
• Various security measures for data protection.
• Cloud vs On-Premise
• URL (DNS-ROOT, TLD, SLD)

Exam Topics

• Applied Mathematics - Data Technology and System Management - Application Development
• File sizes and data capacities
• Virtualization concepts
• Cloud vs. On-Premise differences
• Client-server architecture
• Data transfer rates
• Data security concepts
• Backup and restore strategies
• Knowledge of data exchange methods (interfaces)
• Copyright and data protection laws
• Sorting algorithms, including their applications and performance characteristics.
• Search algorithms, different types of search algorithms and their use cases.
• Object-Oriented Programming (OOP), including the core principles.
• Relational database design.
• Internet basics, Domain Name System (DNS).

Key Notes

• Units must always be included in calculations.
• Results should be shown and explained clearly.
• Documentation is important.
• The "Quick & Dirty" approach

Not Allowed

• ChatGPT
• Full code snippets
• Remote access / GitHub repositories / Cheating
• Competency-based questioning Case study discussions
• Current events in IT security (incidents, developments, etc.)
• Cybersecurity / IT security
• ISO/OSI model / Programming fundamentals
• Solution-oriented thinking

Cyber Defense / Security

• Major security vulnerabilities result in exam failure.
• Review current cyber threats, CERT.at, enisa.europa.eu, Ikarus (forecasts), and BSI
• NIS-2
• Common malware types

Top 10 Risks

• Broken Access Control
• Cryptographic Failures
• Injections
• Insecure Design
• Security Misconfiguration
• Vulnerable and Outdated Components
• Identification and Authentication Failures
• Software and Data Integrity Failures
• Security Logging and Monitoring Failures
• Server-Side Request Forgery (SSRF)

ISO/OSI Model

• ISO = International Organization for Standardization
• OSI = Open Systems Interconnection
• Established: 1977 / SC 16 of ISO
• Mnemonic: All People Seem To Need Data Processing
• ISO/OSI Layer: 7 Application Layer, TCP/IP Layer: Application Layer
• ISO/OSI Layer: 6 Presentation Layer, TCP/IP Layer: Application Layer
• Protocols HTTP, SMTP, FTP, DHCP, Telnet
• ISO/OSI Layer: 5 Session Layer, TCP/IP Layer: Application Layer
• ISO/OSI Layer: 4 Transport Layer, TCP/IP Layer: Transport Layer
• Protocols TCP, UDP
• ISO/OSI Layer: 3 Network Layer, TCP/IP Layer: Internet Layer
• Protocols IP, IPsec, IPv6, ICMP
• ISO/OSI Layer: 2 Data Link Layer, TCP/IP Layer: Network Layer
• Protocol Ethernet
• ISO/OSI Layer: 1 Physical Layer, TCP/IP Layer: Network Layer

Characteristics of Good Software

• Well-specified (designed for a purpose)
• Correct (valid syntax)
• Robust (resilient to errors)
• Usable (accessible, W3C standards, contrast, alt-tags, font adjustability)
• Secure
• Efficient (avoiding unnecessary code)
• Maintainable
• Reusable code (proper variable usage)
• Compatible

Privacy by Design

• Proactive, not reactive

Maximized Privacy Protection

• Ensures that personal data is automatically protected in all IT systems and business practices.
• ISO 25010 is the international standard for software quality criteria.

Data Protection and GDPR

• EU regulation, implemented in Austria's Data Protection Act.
• Regulates the handling of persona data.

User Rights

• Right to information
• Right to rectification
• Right to deletion
• Right to objection
• Right to data portability
• Right to restrict processing
• Right to access

What Qualifies as Personal Data

• Any information relating to an identified or identifiable natural person

GDPR Categories of Data

• General personal data (e.g., name)
• Sensitive personal data (race, ethnicity, political opinion, religion, sexual orientation, trade union membership)
• Genetic data
• Biometric data
• Health data

Data Processing (Manual or Automated)

• Collection, storage, modification, retrieval, organization, usage, linking, disclosure, deletion

The "8 W's" of GDPR Compliance

• Who, What, Where, Why, For What Purpose, Where To, How Long, How Secure?

Roles in GDPR

• Controller (data owner)
• Processor (third party)
• Data Subject (individual whose data is processed)

GDPR Prohibits Processing

• Unless necessary for contract fulfillment (e.g., online order).
• When required by legal obligation (e.g., tax records).
• For vital interests (e.g., medical emergencies).
• Even manual data is covered if stored systematically.

Databases

• A database is an organized collection of structured information stored electronically, usually managed by a Database Management System (DBMS).

Types of Databases

• Relational
• Object-oriented
• Distributed
• Data warehouses
• NoSQL
• Graph databases
• Open-source databases
• Cloud databases
• Multi-model databases
• Document/JSON databases
• Self-managing databases

Key database Types

• Relational
• Object-oriented
• Hierarchical
• Network-based

Database Design

• NoSQL = "Not only SQL" (alternative query methods exist).
• SQLite is suitable for smaller projects (lightweight, text-based, efficient).
• Too many I/O operations can overload servers.

Design Steps

• Requirement Analysis, includes Functional specifications and Contract agreements.
• Conceptual Schema, involves Entity-Relationship Model (ERM).
• Normalized, Logical Schema, including Normalization, Relational Model (for estimations).
• Hardware/OS selection, SQL-based data definitions.
• Testing optimization, application, maintenance, ensuring input validation with both successful and failed test cases.

Common Data Types

• Integers
• Natural numbers
• Fixed-point numbers
• Enumerations (ENUM, SET, etc.)
• Boolean
• Characters (CHAR)

Normalization Forms

• 1st Normal Form (Atomicity): Data must be stored in the smallest meaningful units.
• 2nd Normal Form (Eliminate Redundancies): Functional dependencies must be properly structured.
• 3rd Normal Form (No Transitive Dependencies): All attributes must depend solely on the primary key.

PHP and HTML Basics

LAMP Stack

• Linux
• Apache
• MariaDB
• PHP

Why Apache?

• Best performance for dynamic content (but resource-intensive).

PHP Data Types

• Boolean
• Integer
• Float
• String
• Always explicitly define data types when possible.

Backup Strategies

Which Data to Back Up

• Application data
• System data (system-relevant data)
• Log data (who manipulated data, when, and where)
• Software

Types of Data Backup

• Data mirroring
• Full backup
• Incremental backup
• Differential backup

Backup Types Explained

• Mirror Backup: similar to a full backup, but only the latest file version is stored, and files deleted from the source are also removed from the backup.
• Full Backup: A complete backup stored as a single file on external storage.
• Incremental Backup: Copies only data changed or created since the last backup, reducing storage needs.
• Differential Backup: Copies all files changed since the last full backup, requiring only the full backup and the latest differential backup for restoration.

3-2-1 Backup rule

• Create at least 3 copies of a file.
• Store them on at least 2 different storage media.
• Keep 1 copy in an offsite location (e.g., cloud).

Backup Selection Criteria

• Data volume.
• Backup timing.
• Effort required for restoration.
• Internet connection quality (for cloud backups).

Example Case Study

• Facility data to be structured and stored are company properties and the buildings located on these properties.
• Properties are connected and include name, address, zoning regulations, build regulations and land registry entries.
• Task, to create an Entity-Relationship Model (ERM).
• Task, describe each entity type and relationships in detail, attributes, primary and foreign keys, data types and null unique settings.

Employee Protection - IT Technician Section

• Key topics: Basics, screen work, electrostatic discharge (ESD) practice.
• Laws and regulations, Employee protection Act (ASchG), Electrical Engineering Act (ETG), Workplace Regulation, Screenwork regulation (BS-V).
• Apply screenwork regulations with computer and input device for unit of work.
• Covers tasks such as data entry, transfer, and text processing.
• Break after every 50 minutes of continuous screen work. If not possible the break can be postponed to the next hour.
• Employer must perform regular eye exam and provide glasses if needed.

Workplace space evaluation

• Air volume 12-15m3 per employee, +10m3 for each additional employee; the room height must be a minimum of 2.5m.
• Lighting needs to be natural and even; with 10% of floor area having light entry surfaces.
• Climate is best at 19-25c for low exertion and 40-70% relative humidity; noise needs to be low.

ESD Workplace (Electrostatic Discharge)

• ESD protects components while Antistatic indirectly protects the worker.
• ESD work clothing >5V while antistatic work clothing PPE with 3000V.
• List of equipments for ESD such as desk mats, wrist straps, floors mats, etc.

Data Technology & System Management

• With On-Premise the control is on the data and there is security but there are high costs; with private cloud there is secured virtual enviornment.
• Public Cloud: infrastructure and software is managed by a provider; with a low initial cost but has ongoing expenses.

Cloud Service Models

• IaaS - Infrastructure as a Service
• PaaS - Platform as a Service
• SaaS - Software as a Service

Application Development

• Comparison sorting, like Bubble Sort
• Non-Comparison Sorting, like Bucket Sort
• Data integrity ensures data is consistent and correct, and integrity rules prevent incorrect data entry.
• Types of Relationships are 1:1, 1:N, N:M

Sorting Algorithms

• Comparison-based sorts include Bubble Sort, Insertion Sort, Selection Sort, Shell Sort, Quick Sort, Merge Sort, and Heap Sort.
• Non-comparison-based (address-based) sorts include Bucket Sort, Counting Sort, and Radix Sort.
• A stable sorting algorithm maintains the order of equal elements, and an unstable algorithm does not.

Data Integrity

• Data consistency ensures that stored information is error-free.
• Integrity rules prevent incorrect data entry into databases.

Primary Key

• Uniquely identifies a record.
• Can consist of multiple attributes (e.g., social security number + birthdate).

Foreign Key

• References a record in another table.
• Contains the same values as the primary key but can appear multiple times.

Types of Relationships

• 1:1
• 1:N
• N:M