# The System Industries 9400 and 9900 controllers

These are some very modular SMD disk controllers emulating DEC MASSBUS controllers and their drives. They use two differnd kinds of controller boards, both have connectors for two B-cables but only one has a connector for an A-cable. You can install up to four controller boards, connecting up to eight drives daisy-chained using one controller board with an A-cable connector and three without or four drives using four boards with A-cable connectors. Each controller needs at least one interface board which connects through a ribbon cable to a unibus controller, but you can stuff four of them in to let four VAXen or PDPs access the disks at the same time. I haven't played with them yet, and even if i would hook it up to the -11 i don't think i could find any of the CDC disks they need.

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