Computing Systems Flashcards
(22 cards)
Define Hardware
provides the physical mechanisms to input and output data, manipulating data and controlling the various input, output, storage and communications components.
Define Software
both application and system, which provides instructions that tell the hardware exactly what tasks are to be performed and in what order.
How is data represented for a computer? ie in what form/s.
can be alphanumeric, graphic or any other form. In all cases it is represented in a form that the computer will understand and manipulate.
What is the architecture in computing systems?
It refers to those attributes of a system visible to a programmer. The architecture of a CPU is its instruction set, number of bits used for data representation, addressing techniques etc
What is the organisation in computing system?
It refers to the operational units and their interconnections that realise the architectural specification . Hardware details transparent to the programmer, such as control signals between different functional units, memory type etc
Name the two approaches that are used in computing systems, and which is clearest and most effective.
Top-down approach-starting from a top view and decomposing the system into its subparts. (Clearest and most effective)
Bottom-up approach- starting from the bottom and building up a complete description
What is the structure and the function of computing systems?
Structure-the way the components are interconnected
Function-the operation of each individual component as part of the structure
Name and give examples of 4 computing systems functions.
- Data processing-fundamental types of data/processing
- Data storage-Short/Long term strorage
- Data movement-Input/Output for devices directly connected. Data communication for moving data over long distances
- Control-External (users)/Internal (manage resources)
What is the difference between analog and digital data representation?
Analog data is a continuous representation, analogous to the actual information it represents. eg mercury thermometer.
Digital data is a discrete representation, breaking the information up into separate (discrete) elements.
Why is digital data mainly used ?
Both electronic signals degrade as they move down a line. The voltage of the signal fluctuates due to environmental effects. As soon as an analog signal degrades, information is lost. However, digital signals jump sharply between two extremes. A digital signal can degrade quit a bit until the information is lost.
i.e. signal integrity can be maintained in digital signals.
What can be done to digital and analog signals to regain its original shape after degradation?
They can be reclocked before too much degradation occurs so no information is lost.
Why is Binary representation used?
Because devices that store and manage the digital data are far less expensive and complex for binary representation. They are also far more reliable and electronic signals easier to maintain.
What does ASCII stand for
American Standard for Computer Information Interchange
How many characters can the original ASCII and extended ASCII represent?
original-128
extended-256
Explain what unicode is
Since the extended ASCII is not enough for international use, Unicode is a character set that can represnt 2^16 characters(over 65,000). The first 256 characters correspond to the extended ASCII set.
Explain Overflow
Overflow detects errors in signed (i.e. represents both positive and negative numbers) arithmetic operations. i.e. when the result of the calculation doesn’t fit into the fixed number of bits available for the result.
Explain Carry
Carry detects errors in unsigned (i.e. non-negative numbers) arithmetic operations. It occurs when you cannot properly represent the result as an unsigned value.
What are floating point numbers?
Real or floating point numbers are used in computing systems when the number to be expressed is outside of the interger range or when the number contains a decimal fraction. The number is represented by a fixed number of digits of precision together with a power that shifts the point to make the number larger or smaller.
What is meant by exponential notation?
Exponential notation is simply representing a number in the form A * 10^c, where A is a number that is multiplied by 10 x times. The exponent, x, can be either negative or positive.
Explain what is meant by SEEMMMMM
S- one digit to represnt whether it is negative (5) or negative (0)
EE- two digits to represent the exponent ie >50 = positive, <50 = negative eg 53 = 3 while 47 = -3
MMMMM- The mantissa representation i.e. the numbers
What is normalization?
When necessary, numbers are shifted left byb increasing the exponent until leading zeros are eliminated. eg .MMMMM * 10 ^ EE
For example:
take 246.8035 * 10^0
Shift the decimal point to the right or left by increasing or decreasing the exponent – .2468035 * 10 ^ 3
then format the number – 05324680
(note that the 35 at the end of the number are cut off as it only takes 5 numbers after the decimal point)
Explain what is a synchronous clocked sequential circuit
a digital circuit in which the changes in the state of memory elements are synchronized by a clock signal.
