### aggregation | package | computer programme:

Spreadsheet
* Keep and calculate information, and use it to plot charts and diagrams.
* allow people to create and work with simulations of the real world.
* also are more efficient at copying and duplicating blocks of information
  - have the capability of forming graphs
* are a tool for organizing and analyzing data
  - solving business math problems and for statistical analysis
  - also a great way to organize non-financial information
  - an important business tool that helps one evaluate and analyze information
  - another way of examining series or patterns of numbers
  - applicable for data collection, statistical analysis, and graphical representation
  - everywhere in business
  - famous by it's capacity of working with graphics and numbers
  - highly useful in the organization and management of financial and economic data
  - one of the most popular tools to manage scenarios
* are the building blocks to understanding the creation of any database
  - computer equivalent of the traditional accounting ledger
  - language of business, used to keep financial data
  - to numbers what word processors are to text
  - tools for tabulating and analyzing numerical data
* are useful in analysis of some types of problems and the design of their solutions
  - many science and business applications, as well as other areas
  - very specialized database applications
* can contain numbers, formulas, or words
  - do all kinds of arithmetical operations
* consist of workbooks and worksheets.
* contain rows and columns of data and formulas for calculating the data.
* display columns of numbers, while word processors display columns of text.
* do basic arithmetic in a split second.
* handle text and numerical data differently.
* have tools for automatic formula writing.
* hold pieces of data in cells and the values can be linked by various operators.
* make use of what are called relative cell addresses in copying formulae.
* replace the slide rule of engineers and the calculating machines of office workers.
* use letters, called alpha, to label columns.
* work with rows and columns, like a ledger book.

System program
* are programs.
* computer programme

### aggregation | package | computer programme:

Trojan
* are a form of virus
  - destructive code, hidden inside a seemingly-harmless executable
  - one of the leading causes of breaking into machines
  - programs which do something totally different when they are executed
  - small programs that can provide a host of services to a remote user
  - the most common way of bringing a virus into a system
  - video games
* contain malicious code, that, when triggered, cause loss, or even theft, of data.
* vary in the nefarious acts they perform once inside a machine.

### aggregation | package | computer programme:

User interface
* allow people to operate machines.
* are interfaces
  - primarily software creations
* is an aggregate of means used to facilitate interaction between a user and a program.
+ Kill switch: Safety :: Engineering
  * A 'kill switch', sometimes called an 'emergency stop', is a part of a user interface. User interfaces allow people to operate machines. The kill switch is there for security. Its purpose is to switch off the machine as quickly as possible, or to bring it into a state where it can no longer do harm. It is used in an emergency. In many ways, switching off the machine in an emergency is different from switching it off normally, as it has to avoid injury or harm 'at all costs'.