The Z80(i) was an improved implementation of the Intel 8080 architecture, which was faster, more capable, and much cheaper; alongside the 6502 it was one of the most popular 8-bit processors for general purpose microcomputers and other applications. The CPU was used in the Sinclair ZX80, ZX81, ZX Spectrum and the Amstrad CPC home computers as well as the MSX architecture and the Microbee and Tandy TRS-80. The CP/M operating system (and its huge software library featuring hits like WordStar and dBase) was known to be "the" Z80 disk operating system, and its success is partly due to the popularity of the Z80. The 1985 Commodore 128 added a Z80 to the Commodore 64 hardware allowing it to run CP/M software.