Information Systems and Information Technology Fundamentals
Domain 1 supplies the technical vocabulary that every integration project assumes. The exam rarely tests deep engineering; it tests whether you can classify a technology correctly, place it in the right architectural layer, and choose the right security control for the described situation. Expect single-choice items on the system lifecycle, cloud service models, network layering, encryption, and integration styles such as EAI, SOA, and ESB.
The system as a deliverable
- Information systems have four lifecycle phases: initiation (立项, feasibility), development (planning, analysis, design, implementation, acceptance), operation and maintenance (运维), and retirement (消亡).
- Components to remember: hardware, software, data and databases, networks, people, and procedures.
- Integration levels run from data integration through application integration to business-process integration and portal integration.
- SOA means loosely coupled, reusable services; an ESB handles protocol conversion, routing, and message transformation; a Web Service is described by WSDL, invoked by SOAP, and registered in UDDI.
Technology stack that appears in stems
- Cloud: IaaS rents compute and storage, PaaS rents a runtime and middleware, SaaS delivers a running application.
- Big data's five Vs: volume, velocity, variety, value, veracity.
- IoT layers: perception (sensing), network (transmission), application (business logic).
- Blockchain: distributed ledger, decentralisation, immutability, consensus mechanism.
- 5G service classes: eMBB (bandwidth), mMTC (mass connections), uRLLC (low latency, high reliability).
Security fundamentals
- Symmetric encryption (DES, AES) is fast but has a key-distribution problem; asymmetric encryption (RSA) is slow but solves key exchange.
- A digital signature is produced with the sender's private key and verified with the sender's public key. It gives integrity and non-repudiation, not confidentiality.
- A digital envelope encrypts a symmetric session key with the receiver's public key.
- A firewall filters traffic; an IDS detects intrusions; an IPS detects and blocks them.
- 等保2.0 defines five protection levels, with level three as the common baseline for government and critical systems.
Worked example
A hospital wants a patient-appointment module, will not buy servers, and receives a configurable application over the internet. This is SaaS: the buyer consumes a finished application. If the hospital uploaded its own Java service and rented only the runtime, it would be PaaS; if it rented virtual machines and installed everything itself, it would be IaaS. Reason from what the buyer controls, not from the vendor's marketing language.
Traps that cost marks
- Confusing the OSI seven layers with the TCP/IP four-layer model; know that TCP is transport and IP is network.
- Claiming digital signatures provide confidentiality.
- Mixing up IDS (detection) with IPS (blocking).
- Describing SOA as a product rather than an architectural style.