Qniverter - Q-bus to Unibus converter for VAX 3000s and 4000s

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Email: info@able.com
Qniverter ^TM
Unibus to Q-bus Migration
The EASY WAY

Maintenance cost going out of sight on your VAX 11/7xx, 6xxx, or 8xxx computers?
MicroVAXs sound good but peripheral & controller replacement costs too high?
Specialized Unibus controllers required? Not available on the Q-bus?
Other bus conversion solutions require special software?

ABLE's Qniverter is a bidirectional Q-bus to Unibus software transparent bus converter that requires a single quad-width Q-bus slot in the MicroVAX 3000 or 4000 backplane and allows up to 19 Unibus devices to be connected via a standard Unibus expansion cable.

For an example of a typical installation see the Qniverter Application Note.

For the more technically inclined .........

The Qniverter does a simple translation of Q-bus signals to Unibus equivalents and visa-versa requiring no special software for that process. The only requirement of the Qniverter is that the devices that you are attempting to run are compatible with current Unibus and Q-bus specifications. Typically devices that don't predate the PDP 11/34 or VAX 111/750 will meet this criteria; ie. if they run on a computer younger than these - your OK.

On RARE occasions (less than 1 %) resolvable problems encountered are .....

Some devices that you might want to migrate, may have Q-bus equivalent controllers. In these cases, you might have a minor problem requiring a simple patch to the driver. Unibus DMA devices only have 18 bit addresses and can only address 256Kbytes of memory space, while Q-bus DMA devices have 22 bit addresses for a full 4Mbyte addressing. The extended addressing is handled by a "shadow register" that requires writing different data to the same address on a succeeding write. If the driver thinks you are a 22 bit Q-bus device, it will perform this write operation and overwrite the data in the Unibus device, since no "shadow register" exists. When Q-bus and Unibus devices share the same driver and you wish to use the unibus device on a Q-bus platform, you have to force the driver to take the 18 bit device path.

The Qniverter as a factory default, maps the 18 bit Unibus address space into the lower 18 bit (256Kbyte) space of the Q-bus. This is typically were it should remain. However for custom application that may have other requirements, there are switches that can move the 256Kbyte window anywhere within the 4Mbyte Q-bus space.

The typical installation has NO software issues and the drivers merely migrate over.

Ordering Information:

CR130-1-1, Qniverter Module - Quad width Q-bus board with A&B Unibus connectors
CR132-0-0, MicroVAX FCC cable panel - required for MicroVAX to meet FCC requirements.
538-280-602, Unibus Expansion Cable 12 foot, paddle board style.