KEF11-B CIS chip
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(Redirected from KEF11-B CIS option)
The KEF11-B CIS chip is an option for some PDP-11 CPU boards which use the F-11 chip set; it implements the PDP-11 Commercial Instruction Set.
It consists of six chips containing additional microcode, on a large dual DIP carrier. Due to its large physical size, not all the KDF11 CPUs can use it and the KEF11-A floating point chip at the same time; the KDF11-A CPU is too small to hold them both simultaneously.