STPM ICT 958 flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Digital divide

The gap between individuals and communities with effective access to ICT, including devices, connectivity, and skills, and those without such access, limiting participation in education and the economy.

Moore's Law

The observation that the number of transistors on an integrated circuit roughly doubles about every two years, driving falling cost and rising performance per unit of computing.

Green ICT

Practices that reduce ICT's environmental footprint, such as energy-efficient data centres, plus using ICT to reduce emissions elsewhere, for example teleconferencing and smart grids.

Digital signature legal effect

Under statutes such as Malaysia's Digital Signature Act 1997, a signature created with a licensed certification authority's certified key pair can carry legal recognition; a scanned image cannot.

Two's complement

A signed binary representation in which a negative number is formed by inverting all bits and adding one; an n-bit value spans minus two to the power n-1 up to that value minus one.

Pipelining hazard types

Structural hazards arise from resource conflicts, data hazards from dependencies between instructions, and control hazards from branches that change the next instruction address.

Amdahl's Law

Speedup equals one divided by the sum of the non-parallel fraction and the parallel fraction divided by its speedup, capping gains from parallelising only part of a program.

Cache locality

Temporal locality means recently used data is likely reused soon; spatial locality means nearby addresses are likely accessed next, so caches fetch whole blocks.

RISC versus CISC

RISC uses fixed-length instructions, many registers, and load-store memory access; CISC uses variable-length instructions and permits complex operations directly on memory operands.

Third normal form

A relation is in 3NF when it is in 2NF and no non-key attribute depends transitively on the primary key, eliminating redundancy that causes update anomalies.

Referential integrity

A foreign key value must either match an existing primary key value in the referenced relation or be null, preventing orphan records and inconsistent relationships.

ACID properties

Atomicity means all-or-nothing execution, consistency preserves valid states, isolation prevents interference between concurrent transactions, and durability preserves committed changes after failure.

WHERE versus HAVING

WHERE filters individual rows before grouping, while HAVING filters groups after GROUP BY and typically tests aggregate results such as counts or sums.

Data warehouse characteristics

A data warehouse is subject-oriented, integrated, time-variant, and non-volatile, storing historical data for analysis rather than day-to-day transaction processing.

Binary search complexity

Binary search repeatedly halves a sorted array, running in logarithmic time; it requires sorted data, unlike linear search, which scans sequentially in linear time.

Pass by reference

The callee receives the address of the caller's variable, so assignments inside the procedure modify the original argument rather than a local copy.

Recursion base case

A condition that stops recursive calls without further recursion; every recursive algorithm needs one, and each call consumes stack space until it is reached.

Boundary test data

Values at the edges of a valid input range, such as the minimum and maximum permitted numbers, which most often expose off-by-one and comparison errors.

Merge sort complexity

Merge sort divides the list, sorts halves recursively, and merges them, giving n log n time in all cases but requiring additional memory proportional to the input size.

OSI versus TCP/IP layers

OSI defines seven layers from physical to application; the TCP/IP model merges them into network access, internet, transport, and application layers used in practice.

TCP versus UDP

TCP is connection-oriented with handshaking, acknowledgements, and retransmission, ensuring reliable ordered delivery; UDP is connectionless with lower overhead but no delivery guarantee.

Usable hosts in a subnet

For an IPv4 prefix with h host bits, usable addresses equal two to the power h minus two, after excluding the network address and the broadcast address.

DHCP DORA sequence

Address assignment proceeds through Discover, Offer, Request, and Acknowledge messages, letting a client obtain an IP address, mask, gateway, and DNS servers automatically.

Switch versus router

A switch forwards frames within a local network using MAC addresses, while a router forwards packets between different networks using IP addresses and routing tables.

Lossy versus lossless compression

Lossy compression permanently discards detail the senses barely notice, giving small files for images and audio; lossless compression preserves exact data for later reconstruction.

CSS specificity order

Inline styles override ID selectors, which override classes and pseudo-classes, which override element selectors; when specificity ties, the later rule applies.

Raster versus vector graphics

Raster images store a grid of pixels and degrade when enlarged; vector images store geometric objects and scale without loss but suit only certain illustration styles.

Stateless HTTP

Each HTTP request is independent with no memory of previous requests, so cookies, sessions, or tokens must carry user state across interactions.

Symmetric versus asymmetric encryption

Symmetric encryption uses one shared secret key and is fast; asymmetric encryption uses a public and private key pair, easing key distribution but running much slower.

Hash function integrity role

A cryptographic hash maps data to a fixed-length digest that changes if the data changes, letting receivers detect tampering; hashing is one-way and not reversible encryption.

Firewall types

Packet-filtering firewalls inspect header fields, stateful firewalls track connection state, and application-level proxies inspect payload content at higher layers.

Cloud service models

IaaS provides virtualised compute and storage, PaaS provides a managed runtime for deploying applications, and SaaS provides complete applications accessed over the network.

Blockchain ledger properties

A blockchain is an append-only distributed ledger of hash-linked blocks replicated across nodes, with consensus mechanisms such as proof of work validating new entries.