The Microbee Premium series is a complete redesign of the Small Business Computer (SBC). This computer did away with the two board design and puts 128kByte of dynamic RAM and the floppy disk controller onto the core board itself. This board also included a provision for the addition of the Zilog 8530 SCC chip to facilitate high speed serial transfers.

The SBC was initially released with a drive box which held two DSDD 5.25" drives and later was released with either a 5.25" or a 3.5" drive.

The Premium series motherboard cleaned up a lot of the initial design which was still based on the 50-way connector design. Many improvements were made:

• Provision for on-board real time clock
• Provision for an on-board sound chip
• 40x24 screen format to allow for VideoTex
• Color output was standard
• 50-way Z80 socket on the motherboard
• Improvements to the VDO for glitchless display
• Increase in the Programmable Character Generator (PCG) RAM from 2kByte to 16kByte for unlimited character based graphics.

The Z80 quickly became popular in the personal computer market, with many early personal computers, such as the TRS-80 and Sinclair ZX80, using the Z80 as their central processing unit (CPU). It was also widely used in home computers, such as the MSX range, SORD, and the Amstrad CPC, as well as in many arcade games. Additionally, it was also used in other applications such as industrial control systems, and embedded systems. The Z80 was widely used until the mid-1980s, when it was gradually replaced by newer microprocessors such as the Intel 80286 and the Motorola 68000.

The Z80 microprocessor was developed by Zilog, a company founded by Federico Faggin in 1974. The Z80 was released in July 1976, as a successor to the Intel 8080. It was designed to be fully compatible with the 8080, but also included new features such as an improved instruction set, more powerful interrupts, and a more sophisticated memory management system.

The Z80 quickly became popular in the personal computer market, with many early personal computers, such as the TRS-80 and Sinclair ZX80, using the Z80 as their central processing unit (CPU). It was also widely used in home computers, such as the MSX range, SORD, and the Amstrad CPC, as well as in many arcade games. Additionally, it was also used in other applications such as industrial control systems, and embedded systems. The Z80 was widely used until the mid-1980s, when it was gradually replaced by newer microprocessors such as the Intel 80286 and the Motorola 68000. The design was licensed to Synertek and Mostek as well as the European SGS.

The Z80s instruction set is binary compatible with the Intel 8080, so that 8080 code such as the CP/M Operating System and Intel's PL/M compiler for the 8080 can run unmodified on the Z80. The Z80 had many enhancements over the 8080 such as 16-bit data movement instructions, block copy and block I/O instructions, single bit addressing of all registers, IX/IY offset registers, better interrupt system and a complete duplicate register file for context switching during an interrupt.