THE growth in computer equipment sales in South Korea has been matched by the availability of Korean-language software. Last week saw the launch of the first Korean version of DOS, by Computer Research Association, at the 7th Computer and Software Exhibition in Seoul. Many other local exhibitors showed attractive educational products: ''Alphabet'' and ''Famous Stories'' by KBC are IBM-compatible; and for less than HK$1,000, Korea S/W Dist Co Ltd offers a semi-graphic program for children, an English-Korean dictionary and various games. Samsung, the top electronics company in the country, had an expansive multi-media CD-ROM software catalogue. One of the products is Passgate, designed for students learning English, German, French or Japanese. With an eye on environmental matters, the company's 486 SX-25 desktops boast recycled plastic cases, low consumption, and low EMI radiation. After recording a drop of 1.8 per cent in 1990 over 1989, Korean computer exports are predicted to grow at an average annual rate of 8.5 per cent, amounting to about US$3 billion (HK$23 billion) by 1995. The computer industry as a whole is expected to grow 9.8 per cent annually, to about US$5 billion by 1995. As part of its efforts to support small and medium-size companies, the government bought US$30-million worth of PCs from domestic computer makers. It has also ruled that about 16,000 engineers in military service work in the industry.