Introduction to Computer Science Flashcards
What is data?
Data consis of raw numbers and symbols that can be arranged into meaningful information.
What is firmware?
Firmware describes the instructional software that computer chips have and remains the same over time. They are either used for booting up a computer or electronic devices that always perform the same task, such as your smart refrigerator or a child’s toy.
What is a file?
A discrete unit of data.
What is a pixel?
A single square which is assigned a color and is used to assemble a larger image.
What is the BIOS?
Basic Input/Output System. its functions are: identify hardware components attached to the machine, look for an OS, start the OS. The BIOS handles hardware requests from the operating system, applications, and drivers
What is Machine language?
a set of binary instructions that can be executed directly by a CPU
What is mainframe?
A large, powerful, centralized computer, a mainframe is what terminals connect to for processing requests.
What is ASCII?
This is a binary code scheme where letters, numbers, and symbols are represented by exactly one byte of data.
What is resolution?
The number of pixels able to be displayed, typically expressed as width x height (in pixels).
What is sampling?
This is the representation of analog data by taking samples of the wave values over small time intervals.
What is modem?
Portmanteau of modulator-demodulator. This is a device used to translate one type of signal to another.
What’s the number range able to be represented by a byte?
-128 to 127 (8 bits)
What is the difference between the MDR and the
CIR?
The MDR is responsible for temporarily storing data being read from or written to the memory. CIR holds the current instruction being executed.
Why is propositional logic relevant for computer
science?
Propositional logic forms the basis for circuit design and for the implementation of algorithms in software. In circuit design the logical gates implements the concepts of propositional logic and in the programming languages conditional statements and loop constructs are based on evaluating logical expressions using propositional logic.
What is propositional logic?
Propositional logic deals with the study of propositions and their logical relationships. Logical connectives like negation, conjunction, disjunction are provided to connect propositions.
XML
Extensible Markup Language
What is an IRQ?
An IRQ stands for “Interrupt Request”. A device can send status messages to the CPU by in interrupt request line, labeled from 00 to 15. The CPU interrupts its tasks an executes a corresponding
interrupt handler to perform the necessary acƟons. Each device in a computer system is assigned a unique IRQ number. The CPU uses this number to identify the source of the interrupt and determine the appropriate interrupt handler to execute.
Name a few sorting algorithms.
Bubble sort, quicksort, merge sort, binary insertion sort.
What is a checksum?
A checksum is a small-sized block of data derived from another block of digital data for the purpose of detecting errors that may have been introduced during its transmission or storage.
What is the difference between a bit, a byte and
an octet?
1 byte = 1 octet = 8 bits
How it can be determined in the decimal to binary
conversion if the corresponding digit in binary
representaƟon is a 1 or a 0.
In decimal to binary conversion, you divide the decimal number by 2 repeatedly
while recording the remainders. The remainders will determine if the corresponding
digit in the binary representaƟon is 1 or 0. Lets consider the following example: We
have the decimal number 6. We convert this number to binary as follows: 6/2 = 3
remainder 0 3/2 = 1 remainder 1 1/2 = 0 remainder 1 The binary representaƟon of
the decimal number 6 is: 110 (remainder in reverse order).
What is the default gateway?
The default gateway is the router or device that allows the computer to access other
devices outside of its local network.
What is the parity error-checking?
Communication with telephone-based modems was one bit at a time. For every 7 bits, an 8th parity bit was added for error checking. These basically worked like a very simple checksum. For every 8 bits there must be an even or odd number of ones in the data. If it did not match, then it was assumed there was an error.
What is CRC?
Cyclic Redundancy Check. A block of data is processed through a mathematical algorithm and a result is appended to the data. After the data is sent, a calculation is repeated to check the integrity. The CRC can be applied to any length of binary data and will always return a code of the exact same length. This makes CRC a
“hashing” algorithm
How does TCP/IP error detection work?
TCP/IP divides data into pieces to be sent over a network into segments or datagrams.
These segments have a “header” at the beginning which defines the sending and receiving hosts, transmission settings, and also a 16-bit checksum to verify the data. The maximum size of this segment is ~65kb. When each segment arrives at the destination computer it is checked against the checksum value; if the values don’t match, a retransmit request is sent to the source computer.
TCP/IP also checks for transmission errors on other levels. The
receiving computer must also send an acknowledgement (ACK) for each datagram received. This is accomplished by giving each datagram a sequence number in the header. The recipient machine sends an ACK for each sequence number—if one of the numbers is not acknowledged after a certain period of time, the source computer will retransmit.
TCP/IP will also detect broken routes over the network and re-route to new ones. This is one reason why TCP/IP has been used for decades on the internet: it is fault-tolerant. Part of the network can stop working without taking the entire network offline.
What symbol represents a terminator?
An oval, which is used at the beginning of a flowchart and at all the endings.
What symbol represents a process?
Rectangle. Used for data calculation or filtering.
What symbol represents a decision?
A diamond. There are multiple pathways to take.
What symbol represents input/output?
Parallelogram.
What are multidimensional arrays?
Arrays that contain other arrays. For every dimension, complexity is raised by an exponent.
What is Unicode?
An international encoding standard.
How can alphanumeric symbols from encoding systems such as Unicode or ASCII be sorted?
Since each letter and symbol has a binary value attached to it, that value can be used to sort.
What is bubble sort and what is its complexity?
A simple but inefficient sorting algorithm which iterates all elements multiple times, comparing contiguous elements and swapping them if needed according to the specified criterion. It has a worst-case complexity of O(n^2).
What is the meaning of verification in the
Waterfall Model?
Testing
What is binary insertion sort and what is its complexity?
Binary inserƟon sort is a sorƟng algorithm that uses the same method we used for a binary search—by spliƫng the data in half repeatedly. To sort the data, it builds a new output list and takes items from the input list. The input list are items yet to be sorted, and the output are the ones already sorted. For inserƟng an element from the input list in the output list the data in the output list is spliƩed in half repeatedly unƟl the correct posiƟon of the new element is found.
What is quicksort and what is its complexity?
It works by selecting a ‘pivot’ element from the array and partitioning the other elements into two sub-arrays, according to whether they are less than or greater than the pivot. The sub-arrays are then sorted recursively. This can be done in-place, requiring small additional amounts of memory to perform the sorting. Its average complexity is O(n*log(n)).
