UPMSP Intermediate Computer flashcards

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

Von Neumann architecture

A design in which the CPU, memory, input and output units are connected, and both program instructions and data are stored together in the same main memory, fetched and executed one step at a time.

Program counter (PC)

A CPU register that holds the memory address of the next instruction to be fetched. It is incremented automatically after each fetch so execution proceeds sequentially unless a branch changes it.

SRAM versus DRAM

SRAM stores each bit in flip-flops, is fast and needs no refresh, and is used for cache. DRAM stores bits as capacitor charge, is denser and cheaper, and needs periodic refresh.

Cache memory

A small, fast memory between the CPU and main RAM holding recently used instructions and data. It reduces average access time because most programs reuse the same locations repeatedly.

Two's complement representation

A signed binary method where negative numbers are formed by inverting all bits of the magnitude and adding one. For n bits the range is −2^(n−1) to 2^(n−1) − 1, with a single zero.

Hexadecimal conversion

Each hexadecimal digit represents exactly four binary bits. To convert binary to hex, group bits in fours from the right and pad with leading zeros, then replace each group by its hex digit.

BCD and excess-3 codes

BCD encodes each decimal digit separately in four bits, so 29 is 0010 1001. Excess-3 adds 0011 to every BCD digit, producing a self-complementing code used in some arithmetic circuits.

Parity bit

An extra bit appended to a binary word so the total number of ones is even (even parity) or odd (odd parity). It detects any single-bit error but cannot locate or correct it.

Process state transition

A process moves from new to ready, then to running when scheduled. It goes to waiting when it requests I/O, back to ready when I/O completes, and finally to terminated when it finishes.

Page fault

An interrupt raised when a running process references a page not currently loaded in physical memory. The operating system then loads that page from secondary storage into a free frame.

Round robin scheduling

A preemptive CPU scheduling algorithm giving each ready process a fixed time quantum in turn. It is fair and responsive for interactive systems, but a very large quantum behaves like first-come first-served.

Absolute versus relative path

An absolute path starts at the root, such as C:\Docs\a.txt or /home/ram/a.txt. A relative path starts from the current working directory, such as docs\a.txt.

Flowchart decision symbol

A diamond shape in a flowchart representing a condition with two or more exits, typically labelled Yes and No. It implements selection or loop control in the algorithm.

Call by reference

A parameter-passing method where the function receives the address of the caller's variable rather than a copy, so changes made inside the function affect the original value.

Binary search requirement

Binary search repeatedly halves a sorted array to find a key in O(log n) comparisons. The data must be sorted and randomly accessible; it is much faster than linear search on large arrays.

Recursion base case

The condition in a recursive function that returns a result without calling itself again. Without a correct base case the recursion never stops and eventually exhausts stack memory.

Primary key

A column or minimal set of columns chosen from the candidate keys that uniquely identifies each row in a table. It cannot contain NULL values or duplicate entries.

Third normal form

A relation is in 3NF when it is in 2NF and no non-key attribute depends transitively on the primary key, meaning non-key attributes depend only on the key.

WHERE versus HAVING

WHERE filters individual rows before grouping and cannot use aggregate functions. HAVING filters groups after GROUP BY and is used with aggregate conditions such as COUNT(*) > 2.

ACID properties

Transaction guarantees: Atomicity means all steps or none; Consistency preserves valid database states; Isolation keeps concurrent transactions separate; Durability keeps committed changes after failure.

TCP versus UDP

TCP is connection-oriented, reliable and ordered, using handshakes and acknowledgements, suitable for web and email. UDP is connectionless and unreliable but faster, suitable for streaming and DNS queries.

DNS function

The Domain Name System translates human-readable domain names such as example.com into numeric IP addresses so browsers can reach the correct server. It works like a distributed telephone directory.

Router versus switch

A switch forwards frames within one local network using MAC addresses. A router connects different networks and forwards packets between them using IP addresses and routing tables.

Private IP address ranges

Address blocks reserved for internal networks and not routed on the public Internet: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. NAT translates them to a public address.

CSS rule structure

A CSS rule has a selector identifying elements and a declaration block of property-value pairs, for example p { color: red; font-size: 14px; }. Selectors can target tags, classes or IDs.

HTTP status codes

Three-digit server responses: 200 means success, 301 a permanent redirect, 404 the resource is not found, and 500 an internal server error. The first digit indicates the response class.

Lossy versus lossless compression

Lossy compression discards some data to shrink files greatly, as JPEG and MP3 do. Lossless compression preserves all data exactly, as PNG and ZIP do, allowing perfect reconstruction.

Vector versus bitmap graphics

Bitmap images store a grid of pixels and lose quality when enlarged. Vector images store mathematical shapes and scale without blurring, making them suitable for logos and diagrams in SVG format.

Digital divide

The gap between people who have affordable access to computers, Internet connectivity and digital skills and those who do not, often caused by income, location, age or education differences.

E-waste

Discarded electronic equipment such as old computers, phones and batteries. It contains toxic metals like lead and mercury, so recycling is required to prevent soil and water pollution.

Phishing attack

A fraudulent email, message or website that impersonates a trusted organization to trick users into revealing passwords, OTPs or card details. Suspicious links and urgent demands are warning signs.

Two-factor authentication

A login method requiring two different proofs of identity, typically a password plus a one-time code or biometric. It protects accounts even when the password has been stolen.