The pdp-8e was DECs most succesful system prior to the advent of the pdp-11. It was a 12 bit machine used in an astonishing variety of applications, and really was the first succesful minicomputer, before the term came to be recognised. It was a significant price/performance breakthrough, and a usable system could consist of a single tabletop box and a teletype.

A significant factor in this was that it was the first system that used a standardised hardware bus implementation, the Omnibus, which obviated the need for complex backplane wiring - you simply slotted in a set of cards to do whatever you needed. It is the direct ancestor of the expansion buses in todays pc's.

These racks of assorted horrors are part of the large collection I took away from British Aerospace, Preston, along with the main item, pdp-15(2). In the left-hand picture, from left to right, we have: 2 a pdp-8a with 2 RL01s,  rare fixed head disks (DF32)  and an RX02 8" floppy, a rack with a TU10 tape and controller, and 2 RK05 disks and a pdp-8e with damaged front panel. The right-hand picture is a single 8a processor (bottom) with an RK05 sandwiched between 2 Rx01s.

All this stuff is still in storage awaiting assesment; I only collected it last year. The fixed head disks are a real find, they are the only ones I've ever seen. Shame they don't have the full-rack lights and switches controller. No idea what they were used for, but probably also connected to the hydraulic test rig.