PDP-8/L
Introduction
The PDP-8/L was introduced in 1968 at a cost of $8,900.00. DEC sold 3902 of these systems. This was a low cost, "light weight" version of the PDP-8/I. It re-purposed the 8/I CPU but ran it at a slower 312KHz clock cycle, meaning it could perform an addition in 3.2 microseconds and a subtraction in 6.4 micro seconds. As with the PDP-8/I, it was also implemented with TTL integrated circuit technology.
As this was a lower cost system, there were fewer options available as well. The system was not pre-wired for many options, for example the Extended Arithmetic Element (EAE) was unavailable and main memory expansion was maximized at 8KW. The design goal for this model was to cut costs by reducing complexity. The sales goal was to provide a processor at a lower cost for clients not needing the full number of options that were available with other processors while making the full suite of software products available on other PDP-8 series.
PDP-8/L System
Source: Computermuseum der Stuttgarter Informatik
Note that the wire-wrapped backplane is accessible from the top, whereas the circuit cards are accessible from the bottom of the chassis.
PDP-8/L Options Summary
| Option | Description |
|---|---|
| DW08-A | This was a negative I/O bus conversion option allowing the use of older PDP-8 devices. |
| MC-8/L | Memory Extension Control, bank switching, needed to support more than 4K words of memory. The MC-8/L differed from the MC-8/I of the PDP-8/I in that the Instruction Field and Data Field registers were only one bit wide, not three bits as in the MC-8/I. |
| MP-8/L | Memory Parity. |
PDP-8/E Documents
| Document Name | Order Part No. | Publication Date | Domain |
|---|---|---|---|
| Power Failure Option, Functional Description | DEC-8L-D0BA-D_KP8L | April 1969 | HW |
| Bus Conversion (Positive) Option, Installation Instructions | DEC-8L-D0DA-D_DW08-A | July 1973 | HW |
| Memory Extension Control, Optional Functional Description | DEC-8L-D4BA-D | June 1970 | HW |
| PDP-8/L Maintenance Manual Volume 1 | DEC-8L-HR1B-D | July 1970 | HW |
| PDP-8/L Maintenance Manual Volume 2 | DEC-8L-HR2A-D | February 1970 | HW |
| MC8/LA and MC8/LB Installation Instructions for Memory Extension Options | DEC-8L-I1AA-D | March 1970 | HW |
| PDP-8/L Users Handbook | NA | 1968 | USR |
- Adapted from: https://en.wikipedia.org/wiki/PDP-8