The MDS-800 was designed to provide a comprehensive environment for engineers and developers working with Intel’s microprocessors. It was essentially a self-contained computer system that offered everything needed to develop microprocessor-based applications, including software tools, hardware interfaces, and debugging capabilities. The system was built around Intel’s own 8080 microprocessor, making it highly relevant for the growing demand for microprocessor-based applications in the mid-1970s.

The Intel MDS-800 was a robust and modular system, which included several key components that made it a powerful tool for its time:

• Central Processing Unit (CPU): The heart of the MDS-800 was the Intel 8080 microprocessor, an 8-bit CPU that was one of the first commercially successful microprocessors. The 8080 was capable of addressing up to 64KB of memory and executing complex instructions, making it suitable for a wide range of applications.
• Memory: The MDS-800 typically came equipped with 8KB to 16KB of RAM, but it was expandable, allowing developers to tailor the system to their specific needs. This memory was used for running programs and storing data during development.
• Storage: The system utilized 8-inch floppy disks for storage, which were used to save and load software, data, and projects. The floppy disks were crucial for managing the code and other files necessary for development work.
• Modularity: The MDS-800 featured a modular design, which allowed various hardware components, such as memory and input/output (I/O) modules, to be added or removed as needed. This flexibility made the system adaptable to different development tasks and allowed it to evolve alongside the rapidly changing technology of the time.
• Peripheral Support: The system supported a variety of peripherals, including keyboards, CRT monitors, printers, and paper tape readers. These peripherals made the MDS-800 more user-friendly and versatile, allowing developers to interact with the system and document their work efficiently.

The software environment of the MDS-800 was centered around Intel’s ISIS (Intel System Implementation Supervisor) operating system, which later evolved into ISIS-II. ISIS was a control program designed specifically for development tasks on Intel microprocessors. It provided a range of tools essential for software development, including:

• Assemblers: The MDS-800 included assemblers that converted human-readable assembly language into machine code that the 8080 microprocessor could execute. This was a critical feature for developers, as assembly language programming was the standard method for creating software for early microprocessors.
• Debuggers: Debugging tools allowed developers to test and troubleshoot their code by running programs step-by-step, setting breakpoints, and examining the contents of memory and registers. The ability to debug software in real-time was one of the most valuable features of the MDS-800, as it significantly reduced the time and effort required to develop reliable applications.
• Linkers and Loaders: These tools were used to combine various program modules into a single executable and to load the executable into memory for testing. They were essential for managing larger projects, where different parts of the software were developed separately.
• Editors: Text editors were available for writing and modifying source code directly on the MDS-800. These editors were typically line-based and somewhat rudimentary by modern standards, but they were sufficient for the task of writing assembly code.

One of the most powerful features of the MDS-800 was its ability to work with in-circuit emulators (ICE). In-circuit emulation was a cutting-edge technology at the time, allowing developers to test and debug their microprocessor-based systems in real-time. The ICE module could be inserted into the circuit in place of the actual microprocessor, allowing the MDS-800 to take control of the system’s operation. This capability was crucial for diagnosing hardware and software issues that would be difficult to detect otherwise.

The ICE-80 emulator was a key tool used in conjunction with the MDS-800. It allowed developers to emulate the Intel 8080 microprocessor within their circuits, providing deep insight into how the processor interacted with the rest of the system. The ability to set breakpoints, monitor registers, and step through code in a live environment was invaluable for ensuring that both hardware and software functioned correctly together.

The Intel MDS-800 had a profound impact on the development of early microprocessor-based systems. It was among the first systems to provide a complete development environment, combining hardware and software tools in a way that allowed engineers to efficiently develop, test, and debug microprocessor applications. This system paved the way for the widespread adoption of microprocessors in various industries, including computing, telecommunications, and consumer electronics.

The MDS-800 also set a precedent for later development systems, influencing how they were designed and what features they included. As a result, the MDS-800 is often remembered as a foundational tool in the history of computing, helping to shape the development processes that led to the personal computing revolution.

In summary, the Intel MDS-800 was more than just a development tool; it was a comprehensive platform that provided the foundation for much of the early work in microprocessor technology. Its combination of robust hardware, specialized software, and advanced debugging capabilities made it an indispensable resource for engineers and developers in the 1970s and laid the groundwork for the advanced computing systems that followed.

1. The imm8-82 Central Processor Module, which operates as the Central Processor for the INTELLEC8 /MOD8. In this capacity, it performs the following functions.
   a) It controls the execution of program instructions, sending the appropriate control signals to the other modules which make up the INTELLEC8 /MOD8.
   b) It performs all of the necessary airthmetic, logical, and data manipulation operations necessary for program operation.
   c) It controls overall system timing.
2. The imm6-28 Random Access Memory Module, which provides 4,096 S-bit words of ReadtWrite memory for system use. As many as four cards can be used in a system, for a memory capacity of 16K.
3. The imm6-26 Programmable Read-only Memory Module, which provides up to 4,096 words of Read-only memory in increments of 256 words, and which may be operated in parallel with the system Random Access Memory. Again, more than one card may be used, giving a total Read-only mem ory capacity of 16K words.
4. The imm8-60 Input/Output Module, which provides four eight-bit input ports and four eight-bit output ports for system Input/Output operations. In addition, two of the input ports and two of the output ports may be used with integral Teletype communications circuits to provide Teletype I/O. Up to two of these cards may be used in a system, giving a total of eight input ports and eight output ports.
5. The imm6-76 PROM Programmer Card, which gives the INTELLEC8 /MOD8 system the capability of programm ing Intel 1602A or 1702A Programmable Read-only Memory chips.
6. The Front Panel Controller and Display Console, which provides a means of controlling program execution, program debugging, and INTELLEC8 /MOD8 operation. It also provides displays of system status and information.