KE11-A Extended Arithmetic Element
The KE11-A Extended Arithmetic Element is an autonomous UNIBUS peripheral which can perform a variety of arithmetic or logical operations:
- multiplication
- division
- multi-bit shifts
- logical shift
- arithmetic shift
- normalization
(The last is used for implementation of floating point in software.)
It is implemented as several quad and dual boards, plugged into a custom four-slot system unit (details below).
The KE11-A was originally produced for use with the PDP-11/20, whose KA11 CPU did not have multply, divide, or multi-bit shift operations. As a UNIBUS peripheral, not integrated into the CPU, it was also usable with other models, e.g. the PDP-11/05 and PDP-11/04, which likewise did not implement multiplication in hardware, etc.
The KE11-A can be operated with an optional KM11-A Maintenance Set in order to diagnose faults. It was replaced by the KE11-B Extended Arithmetic Element, a program-compatible re-implementation on a single quad card.
Hardware
The KE11-A consists of 3 quad boards:
- M7210 Data Control
- M7211 Register Control
- M827 Clock and States
and a pair of M234 Register dual-height boards, plugged into the quad custom backplane.
Board locations
These are the board locations for the KE11-A (as seen from the board side of the backplane):
| Connector | ||||||
|---|---|---|---|---|---|---|
| Slot | A | B | C | D | E | F |
| 1 | UNIBUS In | M7210 Data Control | ||||
| 2 | Unused | KM11-A | M234 Register (low byte) |
M234 Register (high byte) | ||
| 3 | G772 Power |
Reserved | M7211 Register Control | |||
| 4 | UNIBUS Out | M827 Clock & States | ||||
