Decline

In many Western countries, the market for cassettes has declined sharply since its peak in the late 1980s. This has been particularly noticeable with pre-recorded cassettes, whose sales were overtaken by those of Compact Discs during the early 1990s. By 1993, annual shipments of CD players had reached 5 million, up 21% from the year before, while cassette player shipments had dropped 7% to approximately 3.4 million.^[18] The decline continued such that in 2001 cassettes accounted for only 4% of all music sold. Since then, the pre-recorded market has undergone further decline, with few retailers stocking them because they are no longer issued by the major music labels.^[17] Sales of pre-recorded music cassettes in the U.S. dropped from 442 million in 1990 to 274,000 by 2007.^[19] In 2009, a record low 34,000 cassettes, and 2,000 of those albums were at least 36 months old, bought at independent retailers in the south Atlantic region, in the suburbs.^[20] Most all of the major U.S. music companies had discontinued them by late 2002 or 2003. However, as of 2010, blank cassettes are still being produced and are sold at many retail stores, and facilities for cassette duplication remain available. Cassette recorders and players are gradually becoming scarcer, but are still widely available and featured in a notable percentage of Hi-Fi systems.^[21]

Cassettes remained popular for specific applications, such as car audio, well into the 1990s. Cassettes and their players were typically more rugged and resistant to dust, heat and shocks than the main digital competitor (the CD). Their lower fidelity was not considered a serious drawback inside the typically noisy automobile interior of the time. However, the advent of "shock proof" buffering technology in CD players, the reduction of in-car noise levels, the general heightening of consumer expectations, and the introduction of CD auto-changers meant that by the early 2000s, the CD player was rapidly replacing the cassette player as the default audio component in the majority of new vehicles in Europe and America.

While digital voice recorders are now common, Compact Cassette (or frequently microcassette) recorders may be cheaper and of sufficient quality to serve as adjuncts or substitutes for note taking in business and educational settings. Audiobooks, church services, and other spoken word material are still frequently sold on cassette, as lower fidelity is generally not a drawback for such content. While most publishers sell CD audiobooks, they usually also offer a cassette version at the same price. In the audiobooks application, where recordings may span several hours, cassettes also have the advantage of holding up to 120 minutes of material whereas the average CD holds fewer than 80.^[21]

While cassettes and related equipment have become increasingly marginal in commercial music sales, recording on analog tape remains a desirable option for some, however that method is recently being overtaken by portable digital recorders. Musicians in the indie rockcommunity have showed slight interest in releasing cassettes. Artists such as Dirty Projectors and Deerhunter have made recent titles available on cassette,^[20] and Thurston Moore of Sonic Youth has claimed "I only listen to cassettes." ^[20]

Diamond Studios of Zimbabwe announced that it will establish a plant to mass-produce cassette tapes to be used as a means to counter piracy.

Still in 2000s, some schools use the format in their education.

Among the last in the developed countries to leave the compact cassette format are artists and groups belonging to the "dansband" genre, who many still in the early 2000s had released their albums both to CD and to compact cassettes. Since many of their fans now are older, they often belong to a generation who was less interested in buying a CD player. However, also in this genre fewer artists and groups release recordings on compact cassette. As late as 2006, Lasse Stefanz and Torgny Melins released their latest albums to both Compact Cassette and CD

Introduction of music cassettes

The mass production of compact audio cassettes began in 1964 in Hannover, Germany. Prerecorded music cassettes (also known as Musicassettes; M.C. for short) were launched in Europe in late 1965. The Mercury Record Company, a U.S. affiliate of Philips, introduced M.C. to the U.S. in July 1966. The initial offering consisted of 49 titles ^[12] However, the system had been initially designed for dictation and portable use, with the audio quality of early players not well suited for music. Some early models also had unreliable mechanical design. In 1971 the Advent Corporation introduced their Model 201 tape deck that combined Dolby type B noise reduction and chromium dioxide (CrO₂) tape, with a commercial-grade tape transport mechanism supplied by the Wollensak camera division of 3M Corporation. This resulted in the format being taken more seriously for musical use, and started the era of high fidelity cassettes and players.^[1]

During the 1980s, the cassette's popularity grew further as a result of portable pocket recorders and hi-fi players such as Sony's Walkman, which used a body not much larger than the cassette tape itself, with mechanical keys on one side, or electronic buttons or display on the face. Sony even made the WM-10 which was smaller than the cassette itself and expanded to hold and play a cassette.^[13]

1979 Sony Walkman

Like the transistor radio in the 1950s and 1960s, the portable CD player in the 1990s, and the MP3 player in the 2000s, the Walkman defined the portable music market in the 1980s, with cassette sales overtaking those ofLPs.^[2][14] Total vinyl record sales remained higher well into the 1980s due to greater sales of singles, althoughcassette singles achieved popularity for a period in the 1990s.^[14]

Apart from the purely technical advances cassettes brought, they also served as catalysts for social change. Their durability and ease of copying helped bring underground rock and punk music behind the Iron Curtain, creating a foothold for Western culture among the younger generations.^[15] For similar reasons, cassettes became popular in developing nations.

One of the most famous political uses of cassette tapes was the dissemination of sermons by the Ayatollah Khomeini throughout Iran before the 1979 Iranian Revolution, in which Khomeini urged the overthrow of the regime of the Shah, Mohammad Reza Pahlavi.

In 1970s India, they were blamed for bringing unwanted secular influences into traditionally religious areas. Cassette technology was a booming market for pop music in India, drawing criticism from conservatives while at the same time creating a huge market for legitimate recording companies and pirated tapes.^[16] In some countries, particularly in the developing countries, cassettes still remain the dominant medium for purchasing and listening to music

History

In 1935, years before the introduction of the Compact Cassette, AEG, released the first reel-to-reel tape recorder (in German: Tonbandgerät), with the commercial name "Magnetophon", based on the invention of the magnetic tape (1928) by Fritz Pfleumer, which was using similar technology, but with open reels, for which the tape was manufactured by BASF. These instruments were still very expensive and relatively difficult to use, therefore were mostly used by professionals in Radio Stations and Sound Studios. For private use the (reel to reel) tape recorder was not very common and only slowly took off from about the 1950s. With prices between 700 and 1500 DM (which would now be about 3100 to 6700 EUR)^[4] still being far too expensive for the mass market and while still using vacuum tubes built very bulky. In the 1960s however the prices dropped, so that Reel-to-Reel Tape Recorders could have been found in the better equipped households from then on.

In 1958, following four years of development, RCA Victor introduced the stereo, quarter-inch, reversible, reel-to-reel RCA tape cartridge.^[5][6] It was a cassette, big (5" x 7"), but offered few pre-recorded tapes; despite multiple versions, it failed.

In 1962 Philips invented the compact audio cassette medium for audio storage, introducing it in Europe in August, 1963 (at the Berlin Radio Show),^{[2][7][8][9][10]} and in the United States (under theNorelco brand) in November 1964, with the trademark name Compact Cassette.

Although there were other magnetic tape cartridge systems, the Compact Cassette became dominant as a result of Philips' decision in the face of pressure from Sony to license the format free of charge. Philips also released the Norelco Carry-Corder 150 recorder/player in the U.S. in November 1964. By 1966 over 250,000 recorders had been sold in the US alone and Japan soon became the major source of recorders. By 1968, 85 manufacturers had sold over 2.4 million players

Compact Cassette

The Compact Cassette, often referred to as audio cassette, cassette tape, cassette, or simply tape, is a magnetic tape sound recording format. Although originally designed fordictation, improvements in fidelity led the Compact Cassette to supplant the Stereo 8 track cartridge and reel-to-reel tape recording in most non-professional applications.^[1] Its uses ranged from portable audio to home recording to data storage for early microcomputers. Between the early 1970s and late 1990s, the cassette was one of the two most common formats for prerecorded music, first alongside the LP and later the Compact Disc.^[2] Cassetteis a French word meaning "little box."

Compact Cassettes consist of two miniature spools, between which a magnetically coated plastic tape is passed and wound. These spools and their attendant parts are held inside a protective plastic shell. Two stereo pairs of tracks (four total) or two monaural audio tracks are available on the tape; one stereo pair or one monophonic track is played or recorded when the tape is moving in one direction and the second pair when moving in the other direction. This reversal is achieved either by manually flipping the cassette or by having the machine itself change the direction of tape movement ("auto-reverse")

Formal methods

Formal methods are mathematical approaches to solving software (and hardware) problems at the requirements, specification and design levels. Examples of formal methods include the B-Method, Petri nets, Automated theorem proving, RAISE and VDM. Various formal specification notations are available, such as the Z notation. More generally, automata theory can be used to build up and validate application behavior by designing a system of finite state machines.

Finite state machine (FSM) based methodologies allow executable software specification and by-passing of conventional coding (see virtual finite state machine or event driven finite state machine).

Formal methods are most likely to be applied in avionics software, particularly where the software is safety critical. Software safety assurance standards, such as DO178B demand formal methods at the highest level of categorization (Level A).

Formalization of software development is creeping in, in other places, with the application of Object Constraint Language (and specializations such as Java Modeling Language) and especially with Model-driven architecture allowing execution of designs, if not specifications.

Another emerging trend in software development is to write a specification in some form of logic (usually a variation of FOL), and then to directly execute the logic as though it were a program. The OWL language, based on Description Logic, is an example. There is also work on mapping some version of English (or another natural language) automatically to and from logic, and executing the logic directly. Examples are Attempto Controlled English, and Internet Business Logic, which does not seek to control the vocabulary or syntax. A feature of systems that support bidirectional English-logic mapping and direct execution of the logic is that they can be made to explain their results, in English, at the business or scientific level.

The Government Accountability Office, in a 2003 report on one of the Federal Aviation Administration’s air traffic control modernization programs,^[2] recommends following the agency’s guidance for managing major acquisition systems by

• establishing, maintaining, and controlling an accurate, valid, and current performance measurement baseline, which would include negotiating all authorized, unpriced work within 3 months;
• conducting an integrated baseline review of any major contract modifications within 6 months; and
• preparing a rigorous life-cycle cost estimate, including a risk assessment, in accordance with the Acquisition System Toolset’s guidance and identifying the level of uncertainty inherent in the estimate.