Modern Computing-Quality requirements

Quality requirements

Whatever the approach to software development may be, the final program must satisfy some fundamental properties. The following five properties are among the most relevant:

• Efficiency/Performance: the amount of system resources a program consumes (processor time, memory space, slow devices, network bandwidth and to some extent even user interaction), the less the better.
• Reliability: how often the results of a program are correct. This depends on prevention of error propagation resulting from data conversion and prevention of errors resulting from buffer overflows, underflows and zero division.
• Robustness: how well a program anticipates situations of data type conflict and other incompatibilities that result in run time errors and program halts. The focus is mainly on user interaction and the handling of exceptions.
• Usability: the clarity and intuitiveness of a programs output can make or break its success. This involves a wide range of textual and graphical elements that makes a program easy and comfortable to use.
• Portability: the range of computer hardware and operating system platforms on which the source code of a program can becompiled/interpreted and run. This depends mainly on the range of platform specific compilers for the language of the source code rather than anything having to do with the program directly.

Algorithmic complexity

The academic field and the engineering practice of computer programming are both largely concerned with discovering and implementing the most efficient algorithms for a given class of problem. For this purpose, algorithms are classified into orders using so-called Big O notation,O(n), which expresses resource use, such as execution time or memory consumption, in terms of the size of an input. Expert programmers are familiar with a variety of well-established algorithms and their respective complexities and use this knowledge to choose algorithms that are best suited to the circumstances.

Methodologies

The first step in most formal software development projects is requirements analysis, followed by testing to determine value modeling, implementation, and failure elimination (debugging). There exist a lot of differing approaches for each of those tasks. One approach popular forrequirements analysis is Use Case analysis.

Popular modeling techniques include Object-Oriented Analysis and Design (OOAD) and Model-Driven Architecture (MDA). The Unified Modeling Language (UML) is a notation used for both OOAD and MDA.

A similar technique used for database design is Entity-Relationship Modeling (ER Modeling).

Implementation techniques include imperative languages (object-oriented or procedural), functional languages, and logic languages.

Measuring language usage

It is very difficult to determine what are the most popular of modern programming languages. Some languages are very popular for particular kinds of applications (e.g., COBOL is still strong in the corporate data center, often on large mainframes, FORTRAN in engineering applications, and C in embedded applications), while some languages are regularly used to write many different kinds of applications.

Methods of measuring language popularity include: counting the number of job advertisements that mention the language^[7], the number of books teaching the language that are sold (this overestimates the importance of newer languages), and estimates of the number of existing lines of code written in the language (this underestimates the number of users of business languages such as COBOL).

Debugging

A bug which was debugged in 1947.

Debugging is a very important task in the software development process, because an incorrect program can have significant consequences for its users. Some languages are more prone to some kinds of faults because their specification does not require compilers to perform as much checking as other languages. Use of a static analysis tool can help detect some possible problems.

Debugging is often done with IDEs like Visual Studio, NetBeans, and Eclipse. Standalone debuggers like gdb are also used, and these often provide less of a visual environment, usually using a command line.

Programming languages

Main articles: Programming language and List of programming languages

Different programming languages support different styles of programming (called programming paradigms). The choice of language used is subject to many considerations, such as company policy, suitability to task, availability of third-party packages, or individual preference. Ideally, the programming language best suited for the task at hand will be selected. Trade-offs from this ideal involve finding enough programmers who know the language to build a team, the availability of compilers for that language, and the efficiency with which programs written in a given language execute.

Allen Downey, in his book How To Think Like A Computer Scientist, writes:

The details look different in different languages, but a few basic instructions appear in just about every language:

• input: Get data from the keyboard, a file, or some other device.
• output: Display data on the screen or send data to a file or other device.
• math: Perform basic mathematical operations like addition and multiplication.
• conditional execution: Check for certain conditions and execute the appropriate sequence of statements.
• repetition: Perform some action repeatedly, usually with some variation.

Many computer languages provide a mechanism to call functions provided by libraries. Provided the functions in a library follow the appropriate runtime conventions (eg, method of passing arguments), then these functions may be written in any other language.

Read more...

Jobs in software

In computing a job (or process) is a term used to refer to a single instance of a program. The term is mostly used on multitasking systems. These are operating systems that are able to process many tasks 'concurrently'; however, this is normally achieved through the illusion of doing a little bit of job A, then a bit of job B, then a bit of job C, but done so quickly that the user sees them as happening at the same time. The term 'time slice' is used for the amount of time that a job gets run for, and the process of going through all the jobs, running each of them for a time slice, is known as a processing cycle. So, job A might get a timeslice of so many milliseconds, and then, whether it's finished or not, it will be job B's turn, and the computer will pause execution of job A, until the other jobs have had their turn, and job A is resumed at where it left off. The software responsible for managing this is known as a job scheduler. Because such systems tend to have many jobs active at any one time, they provide 'job' management facilities that allow the user to stop/pause/restart jobs, and to set priorities on jobs (so that job A might get more 'timeslices' per cycle than other jobs).

Computer programming (often shortened to programming or coding) is the process of writing, testing, debugging/troubleshooting, and maintaining the source code of computer programs. This source code is written in a programming language. The code may be a modification of an existing source or something completely new. The purpose of programming is to create a program that exhibits a certain desired behaviour (customization). The process of writing source code often requires expertise in many different subjects, including knowledge of the application domain, specialized algorithms and formal logic.

Overview

Within software engineering, programming (the implementation) is regarded as one phase in a software development process.

There is an ongoing debate on the extent to which the writing of programs is an art, a craft or an engineering discipline.^[1] Good programming is generally considered to be the measured application of all three, with the goal of producing an efficient and evolvable software solution (the criteria for "efficient" and "evolvable" vary considerably). The discipline differs from many other technical professions in that programmersgenerally do not need to be licensed or pass any standardized (or governmentally regulated) certification tests in order to call themselves "programmers" or even "software engineers." However, representing oneself as a "Professional Software Engineer" without a license from an accredited institution is illegal in many parts of the world.

Another ongoing debate is the extent to which the programming language used in writing computer programs affects the form that the final program takes. This debate is analogous to that surrounding the Sapir-Whorf hypothesis ^[2] in linguistics, that postulates that a particular language's nature influences the habitual thought of its speakers. Different language patterns yield different patterns of thought. This idea challenges the possibility of representing the world perfectly with language, because it acknowledges that the mechanisms of any language condition the thoughts of its speaker community.

Said another way, programming is the craft of transforming requirements into something that a computer can execute.

Read more...

Employment

Employment is a contract between two parties, one being the employer and the other being the employee. An employee may be defined as: "A person in the service of another under any contract of hire, express or implied, oral or written, where the employer has the power or right to control and direct the employee in the material details of how the work is to be performed." Black's Law Dictionary page 471 (5th ed. 1979).

In a commercial setting, the employer conceives of a productive activity, generally with the intention of generating a profit, and the employee contributes labour to the enterprise, usually in return for payment of wages. Employment also exists in the public, non-profit and householdsectors. To the extent that employment or the economic equivalent is not universal, unemployment exists.

Employer

An employer is a person or institution that hires employees or workers. Employers offer hourly wages or a salary in exchange for the worker'slabor power, depending upon whether the employee is paid by the hour or a set rate per pay period. A salaried employee is typically not paid more for more hours worked than the minimum, whereas wages are paid for all hours worked, including overtime.

Employers include everything from individuals hiring a babysitter to governments and businesses which may hire many thousands of employees. In most western societies, governments are the largest single employers but most of the work force is employed in small and medium businesses in the private sector.

Although employees may contribute to an enterprise, the employer maintains control over the productive base of land and capital, and is the entity named in contracts. The employer typically maintains ownership of intellectual property created by an employee within the scope of employment and as a function thereof. These inventions or creations become the property of the employer based on a concept known as "works for hire".

An employers’ relative level of power over employees is dependent upon numerous factors; the most influential being the nature of the employment relationship. The relationship employers share with employees is affected by three significant factors – interests, control and motivation. It is up to employers to effectively manage and balance these factors to ensure a harmonious and productive working relationship.

Interests can be best described as monetary constraints and economic pressures placed on organizations in their pursuit of profits. It covers facets such as labour productivity, wages and the effect of financial markets on businesses.

Wood et al (2004, p 355) describe control as being either output focused, focusing on desired targets with managers defining, and using, their own methods for reaching targets, or process controls, which specify the manner in which tasks will be achieved (Ibid, p. 357). Employer and managerial control within an organization rests at many levels and has important implications for staff and productivity alike, with control forming the fundamental link between desired outcomes and actual processes. Employers must balance interests such as decreasing wage constraints with a maximization of labour productivity in order to achieve a profitable and productive employment relationship.

Motivation is the third and most difficult of the factors for employers to effectively manage in the employment relationship . Employee motivation can often be in direct conflict with control mechanisms of employers, and can be broadly defined as that which energizes, directs and sustains human behaviour ( Stone, 2005, p 412). Dubin (1958, p 213) further elaborates on this, noting motivation as “something that moves a person to action, and continues him in the course of action already initiated.”

The employment relationship is thus a difficult challenge for employers to manage, as all three facets are often in direct competition with each other, with interests, control and motivation often clashing in the equally important quest for individual employee autonomy, employer command and control and ultimate profits.

Read more...

Day Job

A day job is a form of occupation taken by a person in order to make ends meet while working another low-paying (or non-paying) job in their preferred career track. Archetypal examples of this are the woman who is working as a waitress for her "day job", while she tries to become anactress, and the professional athlete who must work as a laborer in the off season because he is currently only able to make the roster of asemi-professional team.

While many people do hold a full-time occupation, the term "day job" is specific to those who hold the position solely to pay their living expenses while working on the job (their "other", not necessarily "night", job) they intend to eventually move over to entirely.

Notable figures who have worked in this configuration include the Wright brothers, who held full-time employment as bicycle repairmen while they experimented on powered flights.

The phrase "don't quit your day job" is used as a humorous response to a poor performance. The phrase implies that the performer is not talented enough in that activity to be able to make a career out of it.

This culture-related article is a stub. You can help by

Read more...

Job may refer to:

• a job (role) served by a person or thing:
• a job opening, a desire by an organization to fill a position
• an odd lot or job-lot is a non-standard quantity purchase performed by jobbers
• a task to be performed:
• Job (software), a scheduled and/or automated task for a computer in a batch processing environment
• Job Corps, a training program administered by the United States Government
• Job Network, a set of employment organizations funded by the Australian Government
• Job (professional wrestling), a wrestling performer who loses a match
• Job's syndrome, another name for the medical condition Hyper IgE syndrome (HIES)
• Boob job, a breast enlargement proceedure
• Job for a Cowboy an American death metal band

in literature:

• Book of Job, part of the Tanakh or Old Testament
• Job (Bible), a character in the Book of Job
• Job, a minor Biblical figure
• Job: A Comedy of Justice, a novel by Robert A. Heinlein
• Job (novel), a novel by Joseph Roth
• La Job, a Quebec adaptation of the British TV series The Office
• Jobs (Remnants), a major character from K. A. Applegate's Remnants series

in sexuality:

• Blowjob, the act of providing sexual stimulation to someone's penis by using another person's mouth
• Handjob, stimulation of the penis or other human sexual body part by the hand; or a task performed by hand rather than manufactured

People named Job or Jobs:

• Steve Jobs, co-founder and CEO of consumer electronics company Apple Inc.
• Job ben Solomon, a Muslim slave who was a victim of the Atlantic slave trade
• Job Cohen, mayor of Amsterdam
• Job de Roincé (1896-1981), French journalist and writer
• Joseph-Désiré Job, a Cameroonian footballer

Read more...