86-DOS
Overview
86-DOS, originally known as QDOS (Quick and Dirty Operating System), is a disk operating system developed by Seattle Computer Products (SCP) for its Intel 8086-based computer kit. It was created by Tim Paterson in 1980 as a temporary solution until Digital Research's CP/M-86 was ready. 86-DOS was later acquired by Microsoft and became the foundation for Microsoft Disk Operating System, which played a pivotal role in the early personal computer revolution.
Development History
Origins
In the late 1970s, the microcomputer industry was burgeoning, with the Intel 8086 microprocessor emerging as a powerful option for personal computers. Seattle Computer Products, a small hardware company, sought to capitalize on this by developing an 8086-based computer kit. However, the lack of a suitable operating system for the 8086 architecture posed a significant challenge. At the time, CP/M, developed by Gary Kildall, was the dominant operating system for 8-bit microcomputers, but its 16-bit version, CP/M-86, was not yet available.
Tim Paterson, an engineer at SCP, took on the task of creating a stopgap operating system. Drawing inspiration from CP/M, he developed QDOS in just six weeks. QDOS was designed to be compatible with CP/M at the application level, allowing existing CP/M software to be easily ported to the new system.
Transition to 86-DOS
QDOS was renamed 86-DOS when SCP began selling it to other hardware manufacturers. The operating system offered a simple command-line interface and supported basic file management tasks. Its architecture was designed to be straightforward, with a single-user, single-tasking environment that was typical of early microcomputer operating systems.
Acquisition by Microsoft
In 1980, International Business Machines Corporation was in the process of developing its first personal computer, the IBM PC. IBM approached Microsoft to provide an operating system for the new machine. Microsoft, lacking an OS of its own, negotiated a deal with SCP to acquire 86-DOS. Microsoft purchased the rights to 86-DOS for $50,000, a decision that would prove to be one of the most significant in the company's history.
Microsoft rebranded 86-DOS as MS-DOS and made several modifications to tailor it to IBM's specifications. The IBM PC, released in 1981, was a commercial success, and MS-DOS became the standard operating system for IBM-compatible PCs, cementing Microsoft's dominance in the software industry.
Technical Features
File System
86-DOS utilized a File Allocation Table (FAT) file system, which was a simplified version of the file system used in CP/M. The FAT file system allowed for efficient disk space management and file retrieval, which was crucial given the limited storage capacities of early microcomputers.
Command-Line Interface
The command-line interface of 86-DOS was modeled after CP/M, with a set of basic commands for file manipulation, such as DIR (to list directory contents), COPY (to copy files), and DEL (to delete files). This interface was familiar to users of CP/M, facilitating the transition to the new system.
Hardware Compatibility
86-DOS was designed to run on the Intel 8086 microprocessor, taking advantage of its 16-bit architecture to offer improved performance over 8-bit systems. The operating system supported a variety of peripheral devices, including floppy disk drives, printers, and serial ports, making it versatile for different hardware configurations.
Legacy and Impact
Influence on MS-DOS
The acquisition of 86-DOS by Microsoft was a pivotal moment in the history of personal computing. MS-DOS, derived from 86-DOS, became the foundation for Microsoft's dominance in the operating system market. Its widespread adoption by IBM and other PC manufacturers established the "IBM-compatible" standard, which persisted for decades.
Contribution to the PC Revolution
86-DOS played a crucial role in the early days of the personal computer revolution. By providing a functional and adaptable operating system for the Intel 8086 architecture, it enabled the development of affordable and powerful personal computers. This accessibility contributed to the proliferation of PCs in homes and businesses, transforming the way people interacted with technology.
Legacy in Modern Computing
While 86-DOS itself is no longer in use, its legacy lives on in modern operating systems. The command-line interface and file system concepts introduced by 86-DOS influenced the design of subsequent operating systems, including Windows. The success of MS-DOS, built on the foundation of 86-DOS, laid the groundwork for Microsoft's later achievements in the software industry.