The Meritum III was not mass-produced. There have been only around 300 pre-production units in existence.

Like the other Meritum computers, the Meritum III used a Z80 clone as its CPU. This CPU was fully compatible with the Z80, and the machine itself was compatible with the TRS-80

This system was meant to be the successor to the Meritum II. A new graphic mode was added giving the machine two new screen modes. A 512x192 monochrome, and a 256x192 4-color resolution graphics mode. The video output was improved by adding an additional RGB signal on a separate DIN socket. The keyboard layout was changed and a new joystick port (DB9 standard) was added. Lastly a second serial port was added. The system was compatible with the Meritum II floppy drive unit.

The Meritum III was never put into production. The Polish Ministry of Education chose the Elwro 800 over the Meritum for use in the schools. Mera-Elzab tried to pursuade the ministry with a proposal to create a networked version of the Meritum, but this never got beyond the expirimental phase. In this set-up a Meritum II, connected with a disk drive, was used as server, while the student computers would be based on the Meritum I.

CP/M (Control Program for Microcomputers), created by Gary Kildall in 1974 for Intel 8080-based systems, was the first widely adopted microcomputer operating system to establish a standard software platform. At its core, CP/M was divided into three layers: the BIOS (Basic Input/Output System) for hardware-dependent routines, the BDOS (Basic Disk Operating System) for file and device abstractions, and the CCP (Console Command Processor) for the command-line interface. This modular design meant CP/M could be ported to a wide variety of 8-bit systems simply by rewriting the BIOS layer, while the BDOS and CCP remained binary-compatible. This allowed application developers to target a single OS API rather than custom hardware interfaces, which was a radical departure from the fragmented landscape of early microcomputers.

Memory management in CP/M was constrained by the 8080 and Z80’s 64 KB address space, so the operating system was designed to occupy only the top portion of memory. The BDOS and CCP were typically loaded into high memory, leaving a contiguous block of low memory available for transient programs (user applications). Applications were written to expect a fixed TPA (Transient Program Area), with the starting address varying slightly depending on how much memory was available after BIOS/BDOS were loaded. This simple scheme avoided the need for virtual memory or sophisticated protection mechanisms, but it limited multitasking: CP/M was strictly a single-tasking environment. Program overlays and clever memory swapping techniques were sometimes used by developers to fit larger applications into the available TPA, especially for compilers and database software.

Application support was the main driver of CP/M’s dominance. Its standardization around the BDOS interface meant that word processors, assemblers, compilers (notably for C, Pascal, and BASIC), and business applications could run on hundreds of different hardware platforms with minimal modification. Programs were distributed as .COM files—binary images loaded directly into the TPA without relocation—which simplified the loader at the cost of flexibility. Libraries like Digital Research’s PL/I subset and third-party toolchains extended CP/M into a development platform, while the vast ecosystem of utilities (from editors like ED to debuggers and communications software) established it as the de facto operating system of the late 1970s and early 1980s microcomputing world. For retrocomputing enthusiasts, CP/M represents the moment when software compatibility, not just hardware, became the central value in the microcomputer marketplace.

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.

Originally the Z80 was intended for use in embedded systems, just as the 8080 CPU. But the combination of compatibility, superior performance to other CPUs of the era, and the affordability led to a widespread use in arcade video game systems, and later in home computers such as the Osborne 1, TRS-80, ColecoVision, ZX Spectrum, MSX, Sega's Master System and many more. The Z-80 ran the original Pac-Man arcade cabinet. The Z-80 was used even in the Game Gear (1990s), and the TI-81 and succeeding graphic calculators.

The Z-80 remained in production until June of 2024, 48 years after its original release. Zilog replaced the processor with its successor the eZ80, an 8-bit microprocessor that features expanded memory addressing up to 16 megabytes, and running up to 50MHz, comparable to a Z80 clocked at 150MHz.