Technology: Data, Systems, Networks, and Security
Technology is the broadest domain on the PhilNITS IT Passport, an entry-level multiple-choice certification aligned with Japan's IPA IT Passport. It tests whether you can follow how data is represented, processed, stored, transmitted, and protected at a definition-and-calculation level, not whether you can configure a vendor product.
Core rules and concepts
- Data representation: binary and hexadecimal conversion; 1 byte = 8 bits; character codes such as ASCII and Unicode; fixed-point versus floating-point.
- Hardware: CPU clock speed, cores, cache; main memory is volatile, secondary storage is non-volatile; RAID levels; input/output devices.
- Software: OS functions (process, memory, file, and device management); application software; middleware.
- Databases: relational tables, primary and foreign keys, normalization, SQL, transactions, and ACID properties.
- Networks: TCP/IP and OSI layering; IP address, DNS, HTTP; LAN versus WAN; a switch forwards by MAC address, a router by IP address.
- Security mechanisms: symmetric versus public-key encryption; hash functions; digital signatures; authentication versus authorization; firewalls.
- Development: SDLC, waterfall versus agile, test levels (unit, integration, system, acceptance), UML diagrams.
Worked example
Four 2 TB disks are configured as RAID 5. Usable capacity is (4 − 1) × 2 TB = 6 TB. One disk's worth of capacity is used for distributed parity, so the array survives one disk failure. RAID 0 would give 8 TB with no redundancy; RAID 1 with two disks would give 2 TB usable.
Traps that cost marks
- Mixing bits and bytes; capacity questions often hinge on the factor of 8.
- Treating RAID 5 as tolerant of two simultaneous failures.
- Reversing key use: public-key encryption uses the recipient's public key; a digital signature uses the sender's private key.
- Confusing authentication (who you are) with authorization (what you may do).
- Calling main memory storage; storage retains data without power.