Question

Giving reasons for your answer, suggest which dependability attributes are likely to be most critical for the following systems: An Internet server provided by an ISP with thousands of customers A computer-controlled scalpel used in keyhole surgery A directional control system used in a satellite launch vehicle An Internet-based personal finance management system.

Short answer

Availability and reliability for ISP server, safety for surgical scalpel, reliability and safety for satellite vehicle, security and integrity for finance system.

Step-by-step solution

Analyze the Internet Server by ISP

An Internet server provided by an ISP with thousands of customers primarily requires high availability. This ensures that the server can handle multiple users simultaneously and maintains continuous service uptime. Reliability is also crucial, ensuring that the server runs without failures over time.

Consider the Surgical Scalpel System

For a computer-controlled scalpel used in keyhole surgery, safety is the most critical dependability attribute. This involves minimizing risks to patients by ensuring precise and controlled operations. Reliability is also important, as the system must function correctly without faults during surgery.

Evaluate the Satellite Launch Vehicle System

A directional control system used in a satellite launch vehicle critically depends on reliability and safety. Reliability ensures that the system performs as expected during the launch, while safety prevents catastrophic failures that could endanger the mission or surrounding areas.

Assess the Internet-Based Finance System

In an Internet-based personal finance management system, security is the top dependability attribute. It is crucial to protect sensitive financial data from unauthorized access and breaches. Additionally, integrity is important to ensure the correctness and trustworthiness of financial transactions and statements.

Key concepts

Availability

Availability is a crucial dependability attribute, especially for systems that need to be accessible at all times, such as internet servers provided by Internet Service Providers (ISPs). These servers host numerous users and run a multitude of applications. When we say a system is highly available, we mean that it can deliver its services continuously without downtime. Think of availability as the reason you can always access your favorite websites, no matter the time or day.
Achieving high availability requires:

• Redundant systems to take over if one fails
• Regular maintenance to prevent unexpected disruptions
• Monitoring to detect and address issues swiftly

Ensuring high availability isn't just about more uptime. It's vital for maintaining user trust and satisfaction, especially in competitive markets.

Reliability

Reliability refers to a system's ability to operate without failure over a specific period. It's about consistency in performance and the confidence users have in the system to function as expected. For example, a satellite's directional control system must reliably guide a launch vehicle without error. Even a tiny failure could lead to catastrophic results.
In practical terms, reliability is enhanced through:

• Thorough testing and validation before deployment
• Resilient system design to withstand and recover from faults
• Predictive maintenance to detect potential issues

Reliable systems are trusted systems, and in many industries, they are essential for operational success.

Safety

Safety is all about protecting both the system and its users from harm. In applications like a computer-controlled scalpel for surgery, safety ensures that procedures do not endanger patient health. The stakes are high, and the margin for error is minimal.
Ensuring safety involves:

• Implementing fail-safes to minimize risk and damage
• Safety certifications and compliance with regulations
• Continuous monitoring and real-time response to unexpected conditions

Safety is not just about compliance, but about responsibility and trust, particularly in sectors like healthcare and aerospace where lives can be at stake.

Security

Security in a system is about safeguarding data from unauthorized access and threats. This is paramount in systems handling sensitive information like an internet-based personal finance management tool. Users expect their personal and financial information to remain private and secure at all times.
Key measures for ensuring security include:

• Data encryption to protect information during transmission
• Implementing strong authentication measures
• Regular security audits and updates to address vulnerabilities

Security goes beyond technical solutions; it includes trust and confidence that users place in a system to protect their data.

Integrity

Integrity ensures that data is whole, accurate, and unaltered. It is particularly critical in systems dealing with financial transactions, such as personal finance management applications. Users need to trust that the information they receive and the transactions they make are precise and authentic.
Steps to maintain data integrity include:

• Implementing checks and validations for data inputs
• Using secure logging to track changes and access
• Fail-safe mechanisms to detect and recover from data corruption

Integrity is a cornerstone of trustworthy systems, providing users with confidence that the information they handle remains consistent and reliable over time.