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70 Cards in this Set
- Front
- Back
Define a Web Log (Blog) |
A web log is a set of entries / diary on the world wide web (which is accessible to any web user.) |
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Define a Data Stucture |
A data structure is a group of related data items |
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Define an Array |
A data structure which is a set of data elements of the same type |
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Define a Record |
A Record is a set of data items all related to a single entity |
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Define what is meant by a Router |
A router is a device in a network which holds information about the addresses of computers in the network |
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Define a Sequential File |
A Sequential file is a where records are stored in key sequence order |
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What is an advantage of an Indexed Sequential File |
An indexed sequential file allows serial access to the records but also access directly via the index, (which will be much quicker). |
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What is the purpose of encryption? |
Files are often encrypted to safeguard the data |
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What is voice recognition? |
The person’s voice needs to have been recorded previously and it needs to be compare with the original |
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What is meant by the term Buffering |
An area of memory used to store data that is in transit between two locations, e.g. moving data between a digital camera and a printer |
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What is double buffering? |
Whilst one buffer is being emptied, another can be filled |
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Advantage of double buffering? |
Quicker, avoids waiting for the data transfer |
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Example of double buffering uses |
In a printer queue/ video stream |
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Define multitasking |
Multitasking occurs when more than one task or application is available to the user at the same time |
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Give 3 examples of an interrupt generated by software |
- Run time error - Input/Output request - Software fault |
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Give 3 examples of an interrupt generated by hardware |
- Keyboard button clicked - Printer run out of paper - Hardware fault |
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How should a design validation be carried out? |
- Check correspondence between the actual design and its specification - Confirm the most appropriate techniques have been carried out - Confirm HCI is appropriate |
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Define a primary key |
A primary key (is a field which) uniquely identifies a record in a database. |
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Define a foregin key |
A foreign key is a primary key from one table, included in another table to form a link |
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What is an index used to |
• improve (read) access times for records • sort the records (for viewing/output) |
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Why are distributed databases often used |
Databases often contain huge amounts of data, It is often more efficient to store data on a number of different computers in different locations to maximize performance. |
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What is distributed in a distributed database? |
Both processing and data |
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3 Methods of defining algorithms |
- Structured English - Flowcharts - Pseudo code |
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What is a parameter? |
A parameter is a variable that can be passed to / from the procedure |
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What are the 2 types of parameter passing? |
ByVal (By Value) ByRef (By Reference) |
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What is the purpose of Backus-Naur Form |
BNF is used to describe (unambiguously) the syntax of a computer language |
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What is meant by the term relocatable code |
Relocatable code is program code which can be moved by the operating system from one area of computer memory to another. |
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Why is it often useful to use subprogram libraries |
Subprogram libraries contain (well-tested) common tasks, etc and can be used by any user, avoiding re-writing. |
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What is the role of a link loader |
A link loader is a software tool which combines already compiled modules into the executable program. |
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Give an example of a linking error |
link editor cannot find a compiled module |
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4 examples of where a queue is an appropriate data structure |
- A printer queue - A keyboard buffer - A download buffer - A processor scheduling queue |
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What is meant by Underflow |
Occurs when the number is too close to zero to bestored by the computer |
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What is meant by Overflow |
Occurs when the number is too large to be stored by thecomputer |
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What is achieving |
Archiving is the process of storing data which is no longer in current use. For example data stored for legal reasons |
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What is meant by a blocked state |
The process is not running because it is waiting for some event(such as an input/output operation) |
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What is meant by a ready state |
The process is not running because another process is currentlybeing run / waiting for processor time |
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A database is known to be in first normal form. Describe the step necessary to ensurethat it is in second normal form. |
Any partial dependencies must be removed |
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Briefly describe how a bubble sort operates |
A pass is made through the data, comparing each value with the following one and swapping them if necessary. A number of passes is made until the data is in order / no swaps |
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State the two main features of a recursive algorithm |
A recursive algorithm is one which calls itself It must also have a terminating condition |
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What is meant by a scripting language |
A scripting language ( is often embedded in other languages and) can addfunctionality to web pages |
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When is a 4GL used and why? |
Used in a relational database system as a query / manipulation language because it is relatively close to natural language so requires less programming skill |
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When is a visual language used and why? |
Used for production of GUI because it may be more intuitive because visual tools are available |
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When is a special purpose language used and why? |
Used for simulation/control applications because it may have special features relevant to the application e.g. time analysis elements |
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When is a stack an appropriate data structure? |
Subprogram return addresses e.g. undo / back |
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What is a network protocol? |
Protocols are necessary to specify data formats, etc, to enable devices to communicate with each other |
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What is serial transmission? |
Data sent bit-by-bit along the same data line |
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What is parallel transmission? |
All bits in a byte are sent simultaneously along separate data lines |
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Why do computer systems sometimes need to deal with data in analogue form? |
Because many input devices (eg microphone, sensor producing continuously varying voltage etc) produce an analogue signal |
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An advantage of a binary tree? |
faster to search/add a value |
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A disadvantage of a binary tree? |
more complex to program / process |
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What is meant by a forms dialogue? |
Computer prompts for input into specific fields on a screen dialogue form |
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What is meant by multiprogramming? |
A method of benefitting from the speed of a CPU compared with slower peripherals |
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What are the steps to get a database from 2NF to 3NF? |
Any transitive dependencies need to be removed to convert from 2NF to 3NF It needs to be ensured that each attribute depends only on the primary key |
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What is the role of an Assembler? |
Converts a low level program to machine code |
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What does an interpreter do? |
An interpreter translates each line of the source program then executes it |
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What does a compiler do? |
A compiler translates the whole source code / program prior to execution |
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Advantage of random access |
Allows very fast access irrespective of position in file – very suitable for large files which need this sort of access |
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Advantage of sequential access |
Easier to program |
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Advantage of indexed sequential access |
Allows faster access than sequential because can move directly to individual records |
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Define the Internet |
The internet is a publicly accessible, international collection of interconnected networks |
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Define Intranet |
Collection of webpages held locally on the server of a organisation such as a company or a college |
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Define Extranet |
Like internet, except it is accessible to certain individuals who are not member of the organisation, such as customers |
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What happens in a left logical shift? |
All digits are moved to the left. The left-most digit is discarded and the new right-most digit becomes a zero. |
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What happens in a right logical shift? |
All digits are moved to the right. The right-most digit is discarded and the new left-most digit becomes a zero. |
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What happens in a right arithmetic shift? |
All digits are moved to the left. The right-most digit becomes a zero and the left-most bit is discarded. This operation can result in overflow, if the left-most bit has changed from a 1 to a 0 or vice-versa. This operation can be used for dividing by two. |
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What happens in a left arithmetic shift? |
All digits are moved to the right except for the left-most bit. The right-most bit is discarded, while the left-most bit remains as it was. This has the effect of making sure that negative numbers remain negative numbers. This operation can be used for multiplying by two. |
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Name the 4 CASE tools |
Source code generation, Data modelling, Refactoring, UML generation |
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What is source code generation? CASE |
The main aim of CASE tools is the elimination of the need for a programmer to create and fine-tune every individual line of code |
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What is data modelling? CASE |
To aid in the development of the way in which data moves around the system and is stored |
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What is refactoring? CASE |
Refactoring is changing the code of a program without changing its function. This might be to make code more readable, more maintainable or quicker in execution. |