Maharashtra HSC Computer Science (Bifocal) flashcards

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

Radix

The base of a number system, showing how many distinct digits it uses: binary radix 2, octal 8, decimal 10, hexadecimal 16.

Universal gates

NAND and NOR gates, called universal because any other logic gate or Boolean function can be built using only NAND gates or only NOR gates.

Half adder

A combinational circuit that adds two single bits; the sum output equals A XOR B while the carry output equals A AND B.

Cache memory

A small, very fast memory placed between the CPU and main memory that holds recently or frequently used instructions and data to reduce average access time.

Multiprogramming

An operating system technique where several jobs remain in main memory at once, so the CPU runs another job whenever the current job waits for input or output.

Time-sharing operating system

An operating system that gives each user or process a small fixed time slice called a quantum, in rotation, so many users get fast interactive response.

Absolute path

A file path starting from the root directory, such as C:\DATA\FILE.TXT or /home/user/a.txt, so it locates a file regardless of the current directory.

Wildcard characters

Filename pattern symbols: the asterisk stands for any number of characters while the question mark stands for exactly one character, as in *.TXT or A?.DOC.

Call by reference

A parameter-passing method in which the function receives the address of an argument, so changes made to the parameter change the original variable in the caller.

do-while loop

A post-test loop in C and C++ whose body executes before the condition is tested, so the body always runs at least once.

Recursion base case

The terminating condition in a recursive function that returns a result without calling itself again, preventing infinite recursion and eventual stack overflow.

Short-circuit evaluation

In C and C++, the AND operator stops once the left operand is false and OR stops once it is true, so later operands may never be evaluated.

Stack LIFO order

A linear data structure in which insertion (push) and deletion (pop) happen only at the top, so the last element inserted is the first one removed.

Circular queue

A queue built on a wrapped array so the rear index follows the front, reusing freed positions and avoiding the false overflow of a linear queue.

Binary search

A search on a sorted array that compares the middle element and discards half the remaining elements each step, giving logarithmic time complexity.

ios::app open mode

A C++ file open mode that places the write pointer at the end of the file, so every write appends data without erasing existing contents.

Primary key

A column, or minimal set of columns, that uniquely identifies every row of a table; it can never contain a NULL value and there is only one per table.

Foreign key

An attribute in one table whose values must match a primary key value in another table, thereby enforcing referential integrity between the two related tables.

Third normal form

A relation in second normal form with no transitive dependency, meaning non-key attributes depend only on key attributes and not on other non-key attributes.

HAVING clause

A SQL clause that filters groups formed by GROUP BY after aggregation has occurred, unlike WHERE, which filters individual rows before grouping.

DNS

The Domain Name System, a distributed naming service that translates readable domain names such as school.edu into the numeric IP addresses used by routers.

UDP

A connectionless transport-layer protocol that sends datagrams without acknowledgements or ordering guarantees, making it faster but less reliable than TCP.

Star topology

A network layout where every node connects to a central hub or switch; failure of that centre disables communication, while one cable failure affects only one node.

Router

A network-layer device that forwards packets between different networks by selecting a path using IP addresses and routing tables.

colspan attribute

An HTML table-cell attribute that makes one cell span two or more columns, written as colspan='2' inside a th or td tag.

img alt attribute

The alternative text displayed or read aloud when an image cannot be shown; it is required for accessibility and helps search engines understand the image.

Ordered list

An HTML list created with the ol tag whose li items are numbered in sequence; the type attribute changes markers to 1, A, a, I or i.

Form action attribute

The attribute of the form tag that gives the URL or server script which receives the submitted form data when the user presses the submit button.

Waterfall model

A linear SDLC model in which requirements, design, coding, testing and maintenance follow one another strictly, leaving little scope for revisiting earlier phases.

Cohesion

The degree to which the elements inside one module belong together; high cohesion is desirable because it makes modules focused, readable and easier to maintain.

Black-box testing

Testing performed without knowledge of the internal code structure, based only on inputs supplied and outputs expected according to the specification.

Feasibility study

An early SDLC activity that checks whether a proposed system is technically possible, economically worthwhile, operationally acceptable, legal and schedulable.