The 9845 system was an amazing piece of hardware, built on state-of-the-art technology and combining the usability of a desktop calculator with the performance and flexibility of a 16-bit minicomputer system. The 9845 system was one of the first systems using a CRT display with graphics capabilities, and it was highly expandable. The flagship of the series, the 9845C, was one of the first color workstations ever. The 9845 series was a wonder of micro-electronics. The 9845A with all of its options included 36 NMOS LSI chips, 19 MSI chips and 75 NMOS ROM chips, and this was the bottom line of the family.

Packages & Options Packages & Options

The 9845 series were available with a large number of configurations. Each configuration was packaged with a certain number of accessories, depending on the type of system. In general, those configurations were described as options, either factory installed or field installed.

The 9845A/S The 9845A/S

The 9845 computer series was introduced with the 9845A/S, implementing most of the basic concepts of the 9845 series.

The 9845A/S The 9835A/B

The 9835 was introduced after the 9845A/S systems with smaller footprint, volume and weight and could be considered as some kind of baby 9845B.

The 9845B/T

The 9845B/T

The 9845B/T was a revised version with extended memory capabilities and some additional modifications. The 9845B already had the final system design and was the best-sold 9845 type. Later an enhanced version with a hardware accelerated display and bit-slice processor was available as 9845B option 200.

The 9845C The 9845C

The 9845C was the color version of the 9845 series, basically a 9845B with hardware accelerated color display. Just as the 9845B, an enhanced version with bit-slice processor was offered as 9845C option 200.

System Architecture System Architecture

The system architecture describes the basic technical hardware structure of the 9845 system and its main components. The system architecture consists of processors, memory, display, interfaces and peripheral components, all interconnected by a versatile bus system. This sections also describes the basic functionality of the components, the I/O mechanisms and some design principles.

Processors Processors

The focus of this section is on the processors, the hearts of each 9845 system. The 9845 is a real dual-processor system. Every 9845 computer has two 16-bit CPU's working in parallel on certain tasks in order to realize short response times and concurrent processing of program execution and I/O procedures. In addition, there are even more mircoprocessors or microcontrollers for the control of the internal peripherals, the display and some of the interfaces.

CRT Displays CRT Displays

The 9845 display unit operates mostly independent from the 9845 mainframe. It receives the data for alpha and graphics display via a digital interface, which is integrated into the display legs. There were three types of display available for the 9845: a standard monochrome display, an enhanced monochrome display with hardware accelerated graphics, and a color display with vector generator engine and own power supply unit.

Assemblies Assemblies

The 9845 was a highly modular system. All hardware functionality was distributed on several PCBs, with interconnections over edge connectors on a large mainboard. The mainboard provided both signal paths and power lines to all assemblies.

Interfaces Interfaces

All external peripherals were connected to the 9845 computer via interface modules which implemented a variety of I/O standards, including RS-232 and HP-IB.

Peripherals Peripherals

In addition to the internal thermal printer and tape cartridge drives, there was a large number of external peripherals available for the 9845 series, including mass storage devices, printers, plotters and input devices.