1️⃣ What is a “Software Development Model”?
- It is a method / way to make software step-by-step.
- It tells how to plan, design, code, test and deliver a project.
- Banks use these models for:
- Mobile banking app
- Internet banking
- KYC / AML / Loan systems
- Core banking upgrades
2️⃣ Waterfall Model – Old, Linear Model
✅ Simple Definition
Waterfall = Work goes in one direction, step by step, no going back.
🔁 Steps (in order) (RD-CT-DM)
- Requirements – What does the bank want? (written in detail)
- Design – How the system will look and work.
- Coding – Programmers write code.
- Testing – Find and fix bugs.
- Deployment – Put system in live use.
- Maintenance – Support, small changes.
⭐ Features
- Linear, sequential (one after another).
- Next phase starts only after previous ends.
- More documentation.
- Works well when requirements are clear & fixed.
👍 Advantages
- ✔ Simple to understand & manage.
- ✔ Easy to plan time & cost.
- ✔ Good documentation → good for audits / regulators (RBI, etc.).
- ✔ Good when changes are very less.
👎 Disadvantages
- ✖ Very rigid – change is difficult later.
- ✖ If requirements were wrong → big loss at end.
- ✖ Customer sees working system only at final stage.
- ✖ Not suitable for fast-changing environment.
🏦 Banking Example (Waterfall fit)
- Implementing regulatory reporting system where RBI rules are clear.
- Core banking system upgrade with fixed requirements.
🧠 Memory Trick:
“Waterfall = One Way Fall” → Once it goes down, it does not come back up. (No going back to earlier phase)
3️⃣ Agile Model – Flexible & Fast
✅ Simple Definition
Agile = Make software in small parts, get feedback, change quickly.
🔑 Main Ideas
- Work is done in small cycles (called iterations).
- After each cycle, we get a working part of the software.
- Easy to change requirements during project.
- Focus is on:
- Working software
- Customer feedback
- Quick changes
⭐ Features
- Iterative (repeat cycles) & incremental (add features step-by-step).
- Customer is involved throughout.
- Less heavy documentation (but still some).
- Team works closely together.
👍 Advantages
- ✔ Handles requirement changes easily.
- ✔ Gives early working software.
- ✔ Customer can see, test, and give feedback quickly.
- ✔ Better for new, innovative, digital projects.
👎 Disadvantages
- ✖ Less documentation → can be problem in bank audits / compliance.
- ✖ Needs an experienced team and close communication.
- ✖ Scope can keep growing (scope creep) → project may delay.
🏦 Banking Examples (Agile fit)
- Mobile banking app with frequent updates.
- Net banking UI changes based on customer feedback.
- Pilot version of Digital Rupee (CBDC) wallet – try, test, improve.
- Online loan application portal where features keep changing.
🧠 Memory Trick:
“Agile = Always Adjust” → Model that always adjusts to change.
4️⃣ Scrum – A Type of Agile
✅ Simple Definition
Scrum = A way of doing Agile using small time-boxed cycles called “Sprints”.
⏱ What is a Sprint?
- A fixed time period (usually 1–4 weeks).
- In each sprint, team plans → works → tests → shows working product.
👥 Roles in Scrum
- Product Owner
- Decides what features are needed.
- Maintains Product Backlog (list of tasks/features).
- Scrum Master
- Ensures Scrum process is followed.
- Removes problems / blockers for team.
- Development Team
- Developers + testers etc. → build the product.
🧩 Main Scrum Meetings (Ceremonies)
- Sprint Planning – Decide what to do in this sprint.
- Daily Stand-up – 10–15 min daily meeting:
- What I did yesterday?
- What I will do today?
- Any problem?
- Sprint Review / Demo – Show completed work to stakeholders.
- Sprint Retrospective – Team discusses what went well / what to improve.
🏦 Banking Examples (Scrum fit)
- Scrum used by bank IT team to:
- Add new features in mobile banking app every 2–3 weeks.
- Develop new digital product (e.g., instant personal loan journey) in sprints.
- Improve Net-Banking dashboard based on feedback.
🧠 Memory Trick – Roles (POS)
- P – Product Owner
- O – (Owner)
- S – Scrum Master
- Team (Dev team – just remember they build)
Or: “PS Team” = Product Owner, Scrum Master, Team
5️⃣ Waterfall vs Agile vs Scrum
| Point | Waterfall | Agile | Scrum (inside Agile) |
|---|---|---|---|
| Type | Model | Approach / Philosophy | Framework of Agile |
| Flow | Linear (one way) | Iterative & incremental | Iterative sprints |
| Change in requirements | Hard | Easy | Easy |
| Delivery of working model | At end | Early & continuous | At the end of every sprint |
| Documentation | Heavy | Medium / light | Medium |
| Best for | Fixed, stable projects | Changing, dynamic projects | Same as Agile, but with more structure |
| Banking fit | Core banking, compliance systems | Mobile/Net banking, digital | Same as Agile, with sprints & roles |
🧠 One-Line Formula:
- Waterfall = Old, straight road.
- Agile = Flexible road with many stops.
- Scrum = Agile + sprints + roles.
6️⃣ Very Likely Exam-Type Points
These are the kind of simple one-liners that often come:
- Waterfall model is:
➤ Linear & sequential model of software development. - In Waterfall, next phase starts only after current phase completes.
- Waterfall is suitable when requirements are clear & do not change much.
- Agile model is iterative and incremental.
- Agile is suitable when requirements change frequently.
- Scrum is a type of Agile framework.
- In Scrum, work is done in short sprints (1–4 weeks).
- Product Owner is responsible for product backlog & requirements.
- Scrum Master helps team to follow Scrum & removes obstacles.
- Daily stand-up is a short daily meeting in Scrum.
- Waterfall has more documentation, Agile has less but enough.
- Waterfall is better for compliance-heavy, regulatory projects.
- Agile/Scrum is better for customer-facing digital products like mobile banking apps.
🔥 “Most Important for Exams
- Waterfall = Linear, sequential, rigid, more documentation.
- Agile = Iterative, flexible, fast feedback, handles changes.
- Scrum = Agile framework with sprints, Product Owner, Scrum Master, Daily stand-up.
- Waterfall best for: Fixed requirements, core banking, compliance systems.
- Agile/Scrum best for: Mobile banking, net banking, digital rupee wallet, customer apps.
⏳ 2-Minute Quick Revision Sheet
Just read this before exam ⬇
- Waterfall
- Linear model: Requirements → Design → Coding → Testing → Deployment → Maintenance.
- No going back easily.
- Good: Fixed requirements, high documentation, bank regulatory systems.
- Bad: Change is difficult, late delivery.
- Agile
- Iterative, incremental.
- Small parts delivered regularly.
- Good: Changing requirements, digital products.
- Focus: Working software + customer feedback.
- Scrum (Agile framework)
- Work in sprints (1–4 weeks).
- Roles: Product Owner, Scrum Master, Development Team.
- Meetings: Sprint Planning, Daily Stand-up, Sprint Review, Retrospective.
- Key Differences
- Waterfall = rigid, one-shot.
- Agile/Scrum = flexible, many small steps.
- Waterfall = more docs, Agile = more feedback.
🧠 Mnemonics Recap:
- Waterfall = One Way Fall.
- Agile = Always Adjust.
- Scrum = Sprints + Roles (PO + SM + Team).