PDP-8/e

Digital Equipment Corporation
Industry	Computer hardware
Founded	May 16, 1957; 69 years ago
Headquarters	Maynard, United States
Products	PDP-8 series minicomputers

Adapted from the English Wikipedia article PDP-8/e, available under CC BY-SA 4.0Updated 8 August 20251 source

The PDP-8/e belonged to the PDP-8 series of minicomputers produced by Digital Equipment Corporation. It was engineered as a cost-effective, versatile computing solution with modular expandability tailored to sophisticated user requirements.

Description

Launched in 1970, the PDP-8/e was one of the earliest minicomputers compact enough to be transported inside a Volkswagen Beetle Convertible. Its initial cost was set at $6,500 (equivalent to about $ today), but after 18 months, the price was reduced to $4,995, making it the sole computer available for under $5,000 at that period.

The typical PDP-8/e configuration comprised a central processor, core memory, a data terminal, tape controller and drive, a programmer’s table, line printer, and the OS/8 operating system. The purchase price also covered installation, training, and ongoing maintenance services.

The CPU operated with a single-address fixed word length architecture featuring 12-bit two’s complement arithmetic and a cycle time between 1.2 and 1.4 microseconds, enabling approximately 385,000 addition operations per second. Designed for broad applicability, it supported more than 60 types of peripheral devices. Its applications ranged widely—from managing scoreboards at Fenway Park to monitoring neurological procedures at Massachusetts General Hospital.

Basic system

The core PDP-8/E configuration consisted of a rackmount or tabletop unit occupying six rack units (6U). It housed the processor, core memory modules, front panel controls known as the "programmer’s console," an interface for external console terminals, and an AC power supply compatible with either 115 or 230 volts.^[1]

Processor options

Extended Arithmetic Element – Facilitates high-speed execution of complex arithmetic operations
FPP-12 Floating Point Processor – Provides dual-processing capability for enhanced computational speed
Power Fail and Automatic Restart – Ensures automatic recovery after power interruptions while safeguarding active programs
Real-Time Clocks – Available in programmable, line frequency-based, or crystal-controlled timing intervals
MI8-E hardware bootstrap – Diode array enabling system startup without manual bootstrap input

Mass storage devices

DECtape magnetic tape units
RX01 8-inch floppy disk drives with 256 KB capacity
RK05 hard disk drives featuring removable cartridges with 2.5 MB storage
Paper Tape Readers and Punches – Capable of punching up to 50 characters per second and reading up to 300 characters per second
Card Readers – Able to process up to 300 cards each minute

Display devices

Video and Writing Tablets – Support alphanumeric and graphic point plotting; include light pen input; enable transmission over telephone lines
Hard-Copy Devices – Include incremental plotters and line printers supporting 64- or 96-character sets with speeds up to 165 characters per second or 356 lines per minute

Data Communication Equipment

Synchronous Communications – Modem interface compatible with Bell 201 and 300 series modems or their equivalents
Asynchronous Communications – Serial line interface supporting multiple Baud rates; available with single or double buffering
Automatic Calling Units – Multiplexer capable of handling 10 channels

Laboratory Equipment

Analog-to-Digital Converters
Digital-to-Analog Converters
Programmable Real-Time Clock
Digital Input/Output
Heathkit EU-801E Laboratory I/O Buffered Interface – Offered a 12-bit wide data port for the PDP-8; commonly utilized in academic research for interfacing purposes

Terminals

CRT and Data Entry Terminals – Alphanumeric keyboards with 16 characters; operated over standard telephone line transmission
Teletype Terminals – Designed for sending and receiving only; support synchronous reading and punching
Hard-Copy Terminals – Equipped with serial or parallel interfaces

External links

↑ PDP-8/E PDP-8/M & PDP-8/F Small Computer Handbook. Digital Equipment Corporation. 1973. pp. 2 Template:Hyp1, 2 Template:Hyp3. Retrieved 2018-08-22.

[1] PDP-8/E PDP-8/M & PDP-8/F Small Computer Handbook. Digital Equipment Corporation. 1973. pp. 2 Template:Hyp1, 2 Template:Hyp3. Retrieved 2018-08-22.

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