KTJ11-B UNIBUS adapter

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KTJ11-B board

The KTJ11-B UNIBUS adaptor is used with the KDJ11-B and KDJ11-E QBUS CPU cards in the special KDJ11 PMI/UNIBUS backplane to add UNIBUS capability to systems built around those cards; the PDP-11/84 and PDP-11/94 systems respectively. It converts the native Private Memory Interconnect (PMI) bus supported by these CPUs to the DEC-standard UNIBUS.

It is a hex-height board (M8191), and can only plug into the special backplane, unique to those systems, which is wired to support it.

Technical details

The KTJ11-B contains a cache, to increase the efficiency of DMA transfers on the UNIBUS; generally, two DMA read cycles on the UNIBUS result in a single PMI bus read operation. The cache contains 32 word-width entries, arranged into 4 independent 8-word sets; the KTJ11-B can thus handle up to 4 simultaneous DMA operations on the UNIBUS efficiently.

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