PEPE - Parallel Element Processing Ensemble
 

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My name is Mark DiVecchio, back in the early 1970's, I worked for Burroughs, Great Valley Labs, where we had a contract to build a prototype of a computer named PEPE - Parallel Element Processing Ensemble.

I was just getting out of the Army and I was offered a job to work on PEPE. My first logic design job. The technical part of my interview was with Carl Semmelhaack. Carl, who also worked on the PEPE program,  was my mentor during my stay at Burroughs.



Click here for a short tutorial on the operation of PEPE.

Much of the group migrated from the ILLIAC IV program. That computer was installed at NASA Ames Research Center in Mountain View, CA. PEPE was a logical follow on project as it had similar architecture but a different purpose.

Here is the final report of the Design Phase of the PEPE program. Burroughs was not involved in that part of the program. Honeywell and Bell Labs worked with SDC on that phase. Burroughs won the contract for the final phase - actually building the first (and only) PEPE. I'm sure that the ILLIAC IV experience helped them get the contract.

I and several of my co-workers were hired as new-grads to work as engineers and programmers on the project. I started work at Burroughs about May of 1973. I was hired by the Federal and Special Systems Group of Burroughs which was headquartered in Paoli, PA. I worked at the Great Valley Labs which was located a few miles away on Swedesford Road near Morehall Road. The GVL buildings are still there but I don't think they are occupied by Unisys.

Here is our first ORG Chart.

In 1976, PEPE was installed at the offices of System Development Corporation in Huntsville, AL. Many of us accompanied PEPE to Hunstville to install it and support its operation. From what I recall, we delivered it around May of 1976 and we stayed to support it until Dec of 1976. Burroughs got us furnished apartments and let us fly home to PA once a month. A few of us stayed in Huntsville for several years with continuing support for PEPE (but not me).



From the Defense Technical Information Center: Real-Time Advanced Data Processing Parallel Element Processing Ensemble (PEPE), Final rept. Oct 1971-Apr 1973:
"The PEPE Program was charged with designing an MSI Model PEPE and a full complement of real-time and support software, and represented the second increment of a three-stage PEPE development effort being sponsored by ABMDA. The first stage was a three-year (1969-1971) PEPE IC model feasibility demonstration program conducted by Bell Telephone Laboratories, with SDC and Honeywell assistance during the last year. The third stage, which has just been initiated, is aimed at fabricating a 36-element MSI Model PEPE and producing the required set of software. This last stage is being performed by SDC, employing the Burroughs Corporation as a subcontractor for PEPE fabrication."
1974 April. Here is a photo of me sitting at my desk at the Burroughs Great Valley Labs in Paoli, PA. I don't remeber who took the photo. There were four engineers in this room - but at least we had walls and a door. I need a haircut.



I did the final design on the PEPE Processing Element (PE). This was a six board unit which consisted of three processors and a common memory. I also worked on the three control units for the array. I did the design on "C" size drafting paper with a green logic template.



The design was done using Motorola MECL 10K and had a 10MHz clock. It was a completely synchronous design and we could run the clock from an external source all the way down to single-step.

My work on the PE was used as my Master's Degree thesis at the University of Pennsylanvia (1978).

More ORG Charts

Sometime in late 1973, the PEPE program suffered a budget cut. I don't remember why but the staffing was almost cut in half. Chuck Yonko wrote: " The big budget cut that left us green horns to finish the job and moved almost all the high priced top experienced staff off to other jobs."

Here is the PEPE org chart right after that cut.

As major pieces of PEPE were completed, people were reassigned. By the end of 1974, the staffing level was where it would stay through the end of the project. Most of the people on this chart accompanied the computer to Huntsville. 

Final PEPE organization chart.

These photos were professionally taken in Hunstville

This is the front of the Processing Element Bay. Each row could hold 9 PE. We built and wired the entire cabinet but only built 11 PE so we could field a row of 9 PE and have a few spares. A full up PEPE could control up to 8 of these PE bays for a total 288 PE. The large box at the end of  each row was a power supply for that row. No more Element Bays or PE were ever built.
Processing Element Bay backpanel view. The power supplies were water cooled. The PEPE control console was in another cabinet. It sent control signals over the ribbon cables to each PE.




The following photos were taken in 1976 by Mark DiVecchio. These were taken with a typical 35mm camera of the day (a Minolta SRT-101) on slide film. The scans of the slides suffer from all the ills of old slides.

High res (600dpi) scans of these photos are available if anyone wants them.


This is the control console. It contained the interface to the CDC-7600 computer used for actual operation and to the B-1700 used for development and testing.
Control Console with doors open.
Power supply. We had a fork-lift sort of device to help us remove the power supplies for maintenance.
It was a switching supply. The diodes in the supply were a real weak point. We had alot of failures of those diodes.
Cooled by chilled water.
Control Console control panel. The LED display showed how many of each of the three units in each PE were online at any time. Notice the external clock BNC connector. PEPE was completely synchronous and could be operated with a clock speed of 10MHz down to a push button rate.
This is is the rear of the control panel.
This is the backpanel of the Control Console.
This is the interface logic.
Front of the PE bay. The top row contained 9 PE. It looks like the second row contained 2 PE.
The card on the far left was for clock distribution to the row.
Backpanel of the Processing Element (PE) Bay.
Note the pattern of daisy chained cables. These cables distributed control signals from the Control Console to each of the 9 processors in each row for a total of 36 processors per bay. The Control Console could then control up to 8 PE bays for a grand total of 288 processors. IIRC we built 9 Processing Elements plus 2 sets of spares and one PE Bay.
Typical PC board of PEPE.
This, I believe, was the Memory Board of a processing element.
Here is a photo of a typical board showing some of the features. I believe this is the Arithmetic Unit (AU) of a processing element. The 24 pin IC were a 4-bit bit slice Arithmetic and Logic Unit (ALU). It appears there were 6 spare IC locations on the board.
PEPE Card/Element Tester. This box could test any of the boards in PEPE.
Burroughs B-1700
Test and Maintanence Control Computer
"IT"
This is the interface logic which connected PEPE to the B-1700 - the test and maintainence interface.
Control Data 7600 - PEPE's main operational interface
System Development Corporaton hosted the BMDATC (Ballistic Missile Defense Advanced Technology Center) in Huntsville, AL.

1976 - I still need a haircut.



Mark DiVecchio standing in front of the PE bay in Huntsville, AL.


When PEPE was officially delivered, we held a party in Huntsville.


PEPE Match Book

PEPE T-Shirt

SDC did up a nice booklet talking about PEPE. The PEPE architecture, design and purpose were not classified. The operational software was.

Click on the scan, above, for a pdf of the entire brochure. In it are photos of Bob Sidnam and Benny Sisk, the two people at SDC that we worked with. Also includes photos of Howard Welsh and Jerry Schweitzer (who worked with me at Burroughs).



I was involved in a couple of patents related to the design. Carl did hard thinking work. I implemented the circuitry in the PE's.



Burroughs acquired System Development Corporation in 1980. It was merged with Federal and Special Systems Group to form "System Development Corporation - A Burroughs Company" in 1982. Burroughs later merged with Sperry Univac to become Unisys - "The Power of 2" (I always said when they came up with that slogan they got the sign wrong - that would have made the merged company the power of -2 or 1/2 of the orginal.).

Bad News on the Doorstep...

In the middle 1990's, I tried to find out what happened to PEPE. I learned that it was eventually installed at Kwajalein Island for system testing.

After it was retired, it was given to Auburn University. I made some phone calls there only to learn that was junked a few years before my search began.



Emails

Alan,

I hope this email gets to you and that you are doing well in your home. San Diego will never be the same.

I'm putting together a web page about the PEPE computer and I was wondering if you have any photos of GreatValley Labs?

Mark
Date:            Sun, 16 Sep 2007 15:35:20 -0600
From:            Alan Whiteman
Subject:         Re: Burroughs GVL

Hi Mark

Hum ... I don't think so - much was lost and discarded when I was packing up and leaving in those frantic last few weeks.

Alan
Date:    Wed, 21 Apr 2010 11:51:43 -0700 (PDT)
From:    Nina Cornell <nina.cornellyahoo.com>
Subject:    PEPE

Read your site on PEPE.  Wondered why you never mentioned Bell Labs (Dave Bergland) and later John Cornell, Project Manager at SDC in re the origins of the computer.

SDC bid and won the contract to build the 13 element processor as conceived by Bell Labs Whippany.  A group from SDC, Santa Monica, Ca. headed by John A. Cornell relocated to Whippany and after a one year transition the group relocated to Huntsville.

Nina Cornell
Nina,

Thanks for your email.

In my lowly position on the PEPE project, I didn't have much contact with the important people at SDC. We worked with Benny Sisk and Bob Sidnam.

I looked at the final report of Phase I of the program and I see the names: J.A. Cornell, G.J. Hanson, and R.G.Mueller. This document was dated 30 Jun 1973 shortly after Burroughs got involved and I got hired.

I would like to learn more about how the project was run during the early phases. We did our design work based on design speciifcations written by Honeywell.

If you have a chance to tell me more, I'll add it to the web page.

Mark DiVecchio
This site prepared and maintained by Mark DiVecchio

email :  markd@silogic.com

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