Software bloat is a process whereby successive versions of a computer program become perceptibly slower, use more memory, disk space or processing power, or have higher hardware requirements than the previous version, while making only dubious user-perceptible improvements or suffering from feature creep. The term is not applied consistently; it is often used as a pejorative by end users (bloatware) to describe undesired user interface changes even if those changes had little or no effect on the hardware requirements. In long-lived software, perceived bloat can occur from the software servicing a large, diverse marketplace with many differing requirements. Most end users will feel they only need some limited subset of the available functions, and will regard the others as unnecessary bloat, even if end users with different requirements require those functions. Actual (measurable) bloat can occur due to de-emphasising algorithmic efficiency in favour of other concerns like developer productivity, or possibly through the introduction of new layers of abstraction like a virtual machine or other scripting engine for the purposes of convenience when developer constraints are reduced. The perception of improved developer productivity, in the case of practising development within virtual machine environments, comes from the developers no longer taking resource constraints and usage into consideration during design and development; this allows the product to be completed faster but it results in increases to the end user's hardware requirements to compensate. The term "bloatware" is also used to describe unwanted pre-installed software or bundled programs. Types of bloat Program bloat In computer programming, code bloat refers to the presence of program code (source code or machine code) that is perceived as unnecessarily long, slow, or otherwise wasteful of resources. Causes Software inefficiency Software developers involved in the industry during the 1970s had severe limitations on disk space and memory. Every byte and clock cycle was taken into account, and much work went into fitting the programs into available resources. Achieving this efficiency was one of the highest values of computer programmers, and the best programs were often called "elegant", a term used by mathematicians to describe a proof which is tidy, parsimonious and powerful. By the 21st century, the situation had reversed. Resources were perceived as cheap, and rapidity of coding and headline features for marketing seen as priorities. In part, this is because technological advances have since increased processing capacity and storage density by orders of magnitude, while reducing