CHARON-11 is a PDP-11 software emulator available from Software Resources International (SRI). CHARON-11 executes binary PDP-11 code like a hardware PDP-11 CPU, and also emulates most PDP-11 peripheral hardware components.

Utilities are available to transfer files between the host system and the emulated environment.

Host system support

CHARON-11 runs as an application on one of the following platforms

• Compaq Tru64® UNIX 4.0 C, D or E on Alpha based systems
• Compaq OpenVMS® 7.2 or higher
• Windows NT® 4.0 on Intel® and Alpha® based systems
• Red Hat® Linux 6
• other platforms on request

For the host system, 64 MB main memory and an Alpha 21164 or Intel Pentium (300 MHz or higher) are recommended to provide adequate performance.
On a 500 Mhz Intel Celeron® processor, CHARON-11 provides an average performance of 3 - 4 times an PDP-11/93. Disk bound operations like Sysgen are much faster, and usually take minutes in stead of hours.

The installation of CHARON-11 requires 10 MB disk space; this does not include the disk space for the PDP-11 disk images.

CHARON-11 can emulate all PDP-11 models which were designed and sold by Digital Equipment Corporation in the past. It supports CPU options, Unibus and Qbus architectures, real time clocks, most disk controllers (including MSCP devices), several tape controllers (including TMSCP devices), nearly all asynchronous serial line options ever build by Digital, as well as printers and Ethernet cards.

Typical CHARON-11 Screen:The PDP-11 console is connected to the internal terminal emulator;the CHARON-11 command window is at the bottom

By means of a configuration file, CHARON-11 builds in less than a second a specific PDP-11 system configuration and boots from its PDP-11 disks (which are in effect files on the host system). As you can archive configuration and disk-image files as usual, you can build libraries of 100's of virtual systems. Since you can run multiple copies of CHARON-11 in parallel, you can replace multiple PDP-11's with one host, or develop PDP-11 at the same time as running production systems.

Since CHARON-11 runs on laptops with Windows NT, this provides a fast and portable development system. The Ethernet card in the laptop can be used to transfer code to other PDP-11 systems via DECnet.

Every effort is made to make the CHARON-11 runtime system behave as compatible as possible with the known PDP-11 hardware behavior. However, a few limitations and incompatibilities do exist depending on the host platform and the application.

CHARON-11 does not contain Y2K non-compliant code. Most PDP-11 hardware did not have a Time Of Year (TOY) clock, hence their emulation does not have date dependent components. The emulation of the TOY clock of the PDP 11/93 and PDP 11/94 is fully Y2K compliant.

CHARON-11 directly executes binary PDP-11 instructions, and does not require or use source code. This implies that Y2K problems in the PDP-11 operating system and applications must be examined separately.

New virtual PDP-11 devices

We took the opportunity, when we designed PDP-11's in software, to create some useful peripherals which never existed in hardware. They are helpful in extending the life of PDP-11 applications on a new host system, by building virtual networks and allowing PDP-11 applications to communicate with applications in the host system:

• The QQ11-N software communication interface provides a high-speed connection between a PDP-11 application running on CHARON-11 and a host platform application. Can also be used as an interface between existing PDP-11 applications and new host based peripheral devices.
• CHANA is a virtual network interface to interconnect multiple copies of CHARON-11 in the same host via a simplified virtual Ethernet card.
• WIRE is a virtual serial line to connect two copies of CHARON-11 running in the same host. Supports asynchronous DECNET.
• Virtual Ethernet implements a virtual network between multiple CHARON-11 instances within one host or within a LAN.
• The BINARY LOADER can load multiple blocks of binary code (e.g bootstrap code) directly into memory.
• The fast clock option accurately handles RT clock interrupts up to 1 kHz under Windows NT.
• VT52/100 terminals can be emulated as a window on the host system console or on a graphics terminal. Mainly intended to display the PDP-11 console, the emulation is a subset of the VT100 functionality.

Replacing special hardware

Not all PDP-11 peripherals have equivalents on a standard host system. CHARON-11 has options to map specific older peripherals to new products:

• The DRV11 parallel interface can be substituted by the National Instruments PC-DIO-96 PnP or the DCI1300 of the Logical company.
• Reception and generation of external signals for the KWV11-A or the KWV11-C can be emulated via the PC-DIO-96 card.
• The ABB ED1000 subsystem bus interface can be substituted by an Ethernet connection via a ED-0210 interface in the ED1000.
• The VT30-H video terminal can be mapped on the host system console, on an RGB graphics card or as a window on a networked PC.

A more generic solution is also available by connnecting existing Qbus or Unibus peripheral hardware to the host system via a PCI to Qbus or Unibus adapter. These adapters can be ordered from us and are made by The Logical Company:

CHARON-11 provides through these bus adapters a fully transparent connection to the original I/O options, and no changes in the PDP-11 operating system software, drivers or applications are required.

For further information, please send an e-mail to:
info@pdp11.de

EQUIcon Software GmbH
Konrad-Zuse-Str. 2
07745 Jena Germany

Tel +49 3641 / 6224 0
Fax +49 3641 / 6224 11