Topic 1: System Fundamentals

Incomplete (but these are minor tidbits)

Changing Software Systems (Consideration)

• Extent of change

• Limitations of new system

• Context in which the system will be used (organizational issues; user roles)

Changing Software Systems (Challenges

• Users don’t like change

• Some features may be omitted

• Old systems may be faster

• Incompatible with other systems

• Data loss/corruption/unusability

• Expensive

Direct Changeover

• Old system stopped, then new started

  • Pros: Changeover swift, new system available immediately

  • Cons: No backup in case of failure

Parallel Changeover

• Old and new system run concurrently - new data entered into both

  • Pros: Backup if new system fail, output from both system can be compared to verify that new system works correctly

  • Cons: Running both systems is expensive

Pilot Changeover

• New system tested with small part of organization, bugs fixed, then

  expanded

  • Pros: All features tested before adoption by whole organization, staff who

    are part of pilot can train others, if failure, only small part suffers

  • Cons: No backup for pilot group in case of failure

Phased Changeover

• introduced in phases, old system gradually phased out

  • Pros: Allows people to get used to new system, training can be done in stages

  • Cons: If system fails, no backup for that part of system

What is data migration?

Moving data from one system to another. Necessary when transitioning to a new system; can be a huge process depending on system sizes.

Possible issues with data migration

Incompatible file formats

• Different systems may use different versions of the same software, so data is stored differently in different file formats due to software differences

Data structure differences

• e.g., arrays in one and linked lists in another

Validation rules

• Differences in what counts as “valid data”

Different data, currency, or character conventions

• e.g., US dates vs EU dates

Legacy Systems

• Old technology, computer system or application

• No longer supported/available for purchase

• Modernization may be expensive or time-consuming

SaaS

Software As A Service

Local SaaS

• Runs on your computer

• One-time fee

• Installation

• Update may not be automatic

• Users may be using different version depending on update status

• Can be used on one computer

Remote SaaS (most commonly asked for)

• Accessed through a web browser

• Subscription fee

• Can use used on any number of computers via web browser

• Automatic Updates

• Users always using the same version

Pros of SaaS

• Employees can operate software from anywhere

• Cheaper

• Fewer support staff necessary

• Pay as you go/Subscription model

• Scaling up to serve more users easy

  • Easier to maintain - don’t need to worry about individual computer problems

Cons of SaaS

• Users have no control over availability of system

• Users have no control over security

• If SAAS provider gets acquired, user has no control over system

• Large-scale data corruption possible

Static Testing

Testing that checks if the correct system is being built; checks the plans in place. Verifies documentation and planned specifications. D

Dynamic Testing

Makes sure code is executed and produces the desired result (it validates the software). Checks for bugs and checks that the software achieves business requirements.

Alpha Testing

Testing done by the internal team that lasts for months. Confirms that software works as intended and looks for any bugs/UI issues to fix.

Beta Testing

Testing done by potential end users outside the company. Lasts for weeks, largely unstructured, seeking to model a real world environment and get feedback from users. Uses feedback to fix bugs and make software more useful for end users.

Black Box Testing

Tests software through using it. No access to codebase or internal workings; no programming knowledge required.

White Box Testing

Tests a program’s code to make sure everything is working. Knowledge of programming required as it is done by programmers.

User Acceptance Testing

“End user testing,” product is tested by intended audience.

Automated Testing

Uses automated testing software with preconstructed tests, usually specified or software or written into code. Output is automatically compared to expected output. Easily completes complex/tedious tasks.

User Documentation Types

Manual, Online, Help Files

Pros and Cons of Manual Documentation

(Paper manual, booklet, or pamphlet)

• Pros: Doesn’t require installation, computer, or internet connection

• Cons: Can be damaged or lost, cannot be updated

Pros and Cons of Online Documentation

(PDFs, website, video)

• Pros: Can be much longer than manual, can be updated, search capabilities, can be updated easily

• Cons: Internet required, can be difficult for inexperienced users to access

Pros and Cons of Help Files

(Locally accessible programs that display text)

• Pros: Easily accessible in software program, contain general instructions for use, easier to access for inexperienced users

• Cons: Requires installation first, which can be difficult for inexperienced users, lacks search capability

User Training Methods

In-person classes

• Pros: Cheap (many students for one instructor)

• Cons: Less personalized, students may become bored, lost, or lose pace

Online training - Instructor training one student or small group of students

• Pros: Can be more personalized, focuses on needs of students via online instructor

• Cons: Can be more expensive if individual

Self-instruction

• Pros: Low-cost (no teacher needed), flexible timeline, users can choose what to focus on

• Cons: No guidance, users may feel lost, lack of structure means that users may not learn everything then need to

Causes of Data Loss

• Hardware/System Malfunction

• Human Error

• Software Corruption

• Malicious Software (Viruses, etc.)

• National Disasters (Power cuts = equipment damage)

Ways of Preventing Data Loss

• Failover Systems - there is a secondary system that can be switched to if the primary system fails

• Redundancy - a duplicate of a system’s components and data are duplicated so that a backup is present

• Removable Media - removal storage device can be used for data backup

• Offsite/online storage - data is backed up at a different location or in the “cloud

• Physical Security - data is secured from natural disasters or physical tampering

Stakeholder

A person with an interest in something

Getting Feedback from Stakeholders

Direct Observation - observe the system in use in the real-world

• Pros: Opportunity to see users using a produce

• Cons: Users may act differently under observation

Interviews

• Pros: Asking users directly for feedback can be very insightful

• Cons: Costly in times and resources

Surveys - Send users to questionnaires

• Pros: Cheap and time-efficient

• Cons: Hard to think of good question, Users may not take it seriously