multitude of programs developed under the CP/M operating system, including the dBase II database and the WordStar word processor. There was also a third-party 6809 card that would allow OS-9 Level One to be run. Third-party sound cards greatly improved audio capabilities, allowing simple music synthesis and text-to-speech functions. Eventually, Apple II accelerator cards were created to double or quadruple the computer's speed. Rod Holt designed the Apple II's power supply. He employed a switched-mode power supply design, which was far smaller and generated less unwanted heat than the linear power supply some other home computers used. The original Apple II was discontinued at the start of 1981, having been superseded by the Apple II+. By 1984, over six million machines had been sold. Apple II Plus The Apple II Plus, introduced in June 1979, included the Applesoft BASIC programming language in ROM. This Microsoft-authored dialect of BASIC, which was previously available as an upgrade, supported floating-point arithmetic, and became the standard BASIC dialect on the Apple II series (though it ran at a noticeably slower speed than Steve Wozniak's Integer BASIC). Except for improved graphics and disk-booting support in the ROM, and the removal of the 2k 6502 assembler/disassembler to make room for the floating point BASIC, the II+ was otherwise identical to the original II. RAM prices fell during 1980–81 and all II+ machines came from the factory with a full 48k of memory already installed. Apple II Europlus and J-Plus After the success of the first Apple II in the United States, Apple expanded its market to include Europe, Australia and the Far East in 1979, with the Apple II Europlus (Europe, Australia) and the Apple II J-Plus (Japan). In these models, Apple made the necessary hardware, software and firmware changes in order to comply to standards outside of the US. Apple IIe The Apple II Plus was followed in 1983 by the Apple IIe, a cost-reduced yet more powerful machine that used newer chips to reduce the component count and add new features, such as the display of upper and lowercase letters and a standard 64 KB of RAM. The IIe RAM was configured as if it were a 48 KB Apple II Plus with a language card. The machine had no slot 0, but instead had an auxiliary slot that could accept a 1 KB memory card to enable the 80-column display. This card contained