The Dubna 48K (Дубна 48К) is a Soviet clone of the ZX Spectrum home computer. It was based on an analogue of the Zilog Z80 microprocessor. Its name comes from Dubna, a town near Moscow where it was produced, and "48K" stands for 48 KBs of RAM.
According to the manual, this computer was intended for:
- studying the principles of PC operation
- various kinds of calculations
- "intellectual games"
By the time this computer was released (1991), there were already much more powerful x86 CPUs and commercially available advanced operating systems, such as Unix, DOS and Windows. The Dubna 48K had only a built-in BASIC interpreter, and loaded its programs from a cassette recorder, so it couldn't run any of the modern operating systems, and as such, wasn't suitable for "studying the principles of PC operation". However, the Dubna 48K and many other Z80 clones, hopelessly outdated by that time, were largely introduced in high schools of the Soviet Union. Many of the games for the Z80-based machine were ported from games already available for Nintendo's 8-bit game console, marketed in Russia under the brand Dendy.
Source: Wikipedia, "Dubna 48K", available under the CC-BY-SA License.