The 1983 Altos Model 5-15ED was an 8 bit microprocessor based system with dual floppy and Winchester hard disk together with single board microcomputer technology.

The Altos Series 5 computer system was a Z80A-based multiuser system designed to fit many commercial, technical, industrial, Scientific, and educational applications. It ran under either CP/M, MP/M II, or OASIS operating systems. In its basic figuration, the system was contained in a single chassis, however additional chassis could be connected to the basic chassis to increase system capabilities*

The basic computer system includes the CPU, four RS-232-C ports, one parallel port, 192 kilobytes of RAM, all peripheral Controllers, and one 5-1/4 inch floppy disk drive. You have to add a keyboard terminal, provide your own floppy diskettes and cabling.

Series 5-5D also included a five-megabyte drive and a five-inch hard disk drive.Series 5-15D also included a second one-megabyte disk drive unit.

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.