Introduction: what this topic is and why it matters
Modern digital services — mobile banking, e-governance, online exams, social media — all run on three linked ideas. Data centres are the physical buildings full of computers where data lives and is processed. Big Data is the science of storing and making sense of the enormous, fast-moving data these centres hold. Blockchain is a tamper-proof way of recording transactions across many computers without a central boss.
For BCS, Bank and IT-officer examinations these three areas are heavily tested because they combine hardware facts (Tier standards, redundancy, PUE), analytical concepts (the five Vs, Hadoop) and current-affairs facts (Bangladesh National Data Center, blockchain in banking). This lesson teaches every term from first principles, works through the numerical items step by step, and ends with practice, exam tips and a summary.
Learning objectives
- Identify the five core components of a data centre and the role of DCIM.
- State the four Uptime Institute Tiers (I–IV), their availability percentages and redundancy levels.
- Define and calculate PUE and explain N+1 and 2N redundancy.
- List the key design factors for a banking data centre.
- State the facts about the Bangladesh National Data Center and BDCCL.
- Explain Big Data and the five Vs, Hadoop (HDFS + MapReduce), dark data, and data lake vs data warehouse.
- Explain blockchain — blocks, hashing, the chain, distributed ledger, PoW/PoS consensus, immutability, the 51% attack, satoshi and smart contracts, plus banking use cases and DLT.
- Recall the IoT architecture, RFID and edge computing.