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SEREL computers

En français

These 2 described machines are the 2 first french computers made with transistors, designed by french on the french territory. (as explained by my old colleagues in 1969/70) They have been built in less then 10 exemplaries...
I stocked these 2 machines during 37 years and begin to analyze them! The small one was built in 1962, and the big one probably before...
Unfortunatly i have no drawings of these machines. If you have information about them, do not hesitate to contact me (at without the 1234 number: ie pichotjm@free...)

If you read french, i have 5 notices explaining the hardware and programming manuals!

These computers are unique survivors of the second generation of computers. All brothers have been destroyed...

[First generation with valves,
2nd with transistors,
3rd with small IC (ex '74 series or ECL) and
4th with uP...]

You can come and discuss on the following forum:
Every people in computer science read/write english. Use simple english.

Site description

ODP-505 restoration:

I have finished to restore the small machine... what a hard work!   (Today, the work is done at 100%).

You can read many information following this link ODP-505 restoring You will find these subjects:

Brief description
The place of the ODP-505 in the computer history
Technology details PCBs, solder, ...
What would it be able to do today?
Biography of this machine
Description of the machine (not yet done)

 and a high amount of photographies.  I hove you will enjoy the work I have done.

OA-1001 restoring:

We just transport the big computer (september 8, 2007). We were 6 men and without any elevator!
The task was huge and difficult. It's very heavy! To minimize the weight, my 3rd son and I
have extracted some racks with many difficuties. Big use of antirust liquid (during several months),
and some foot kik to unlock racks...

Notice precises 'dust proof machine'. I can assure you that after 47 years dust is here! and rust too!
(balls of extractive mechanisms)

We were not able to stand up the computer: too heavy, too tired, too dangerous.
It was dangerous to move it out of the truck. Gods were in a good day.
Coloss stands now on the ground, and this will give me the ability to acces to some parts of the machine.
We were not able to put the machine in a special prepared room (with less humidity): too big!

Voilà, i can now start restoring the machine... but a huge task is waiting! colossal!
The cpu machine is bigger than the ODP-505 machine. Lot of power supplies, with sequencing logic.
There is, too, data logging system (ADC), interfaces to outside (keyboard system), to Friden machine (kind of Teletype?) and so on, i have to discover this world...

I need courage to begin.
I will publish, following months, the restoring state... this will probably need several years!

OA-1001 restoring state url to be written! (The machine is restored to 0%).

I would like to thanks my 3 sons Nicolas, Renaud, Quentin, my wife Anne and my brother Michel, for helping me to transport the machine. They have made about 750 km (500 miles) to help me (each).
My 4th son, Philippe, was in USA, but he will help all of us to stand up the machine at Xmas 2007!


Fortunatly, i have saved 5 marvellous notices concerning these 2 machines. (but sorry, most in french)
It is interesting to have a look, just to see OP code / Op description, schematics or block diagrams.
If you know assembler, you will find information and have ideas.
If you know hardware, you will understand some schematics.
Descriptive notices of the machines
OA-1001 Design and hardware description notice
1rst part
This document deeply describes the hardware operation of the computer (germanium cpu, powers and interfaces).
Description goes to bit level, and give information about priority system, bus operation, accumulator and registers. (fabulous! but sorry, in french.)

notice (text mode) Design and hardware description
notice (thumbnails mode) Design and hardware description

2nd part
Schematics of the OA-1001 design and hardware description
You will find block diagrams, theorical timings, functionnal blocks

Schematics (text mode) OA-1001 machine
Schematics (thumbnails mode) OA-1001 machine

Component specifications

Core memory:

Waiting 2 bunches of cards drying... I prepared this chapter on Ferrite core memories. (Today, only pictures)
This is very impressive to discover. Note the dimensions of the card comparing it with the hand.
I take pictures with different lights.
Note the color of wires. You can see too, some missing or destroyed cores... and a lot of dust!
I was afraid to destroy the card during cleaning.

Memory pictures.

Restoring of a 13 bit ADC converter (Analog to digital converter):

I lasted my week in restoring this very old converter [1964]
Just for training me, because it is a rack... I published, on line, many photos describing
several phasis of the restoration. Many do not have any merit to be published
(no interest, they are very similar). It will be able, in the futur, to compare status.
We can see that cleaning and preserving processes lead to loss 5 transistors.

This rack seems to be incomplete, because i think it must have 58 cards!
I have another converter, quite similar, but with lacking cards. It will be restored ...another
month... Have a look in OA-1001 restoration project.

ADC rack restoration (100% of the rack is restored).

Photos at discovery and explanations:

Some photos describing machines (not restaured) and details of a rack.
Look at the photos and information...

Some information concerning the heath of machines, how to clean them, some details of PCB.

Read information...

on 2007-03-29
Created by hand!
(rev 2007-03-29, 2007-05-15)
(rev 2007-09-14, hardware notice, OA-1001 Transportation)
2009-01-13 Transistor specs
If somebody wants to correct my poor english, feel free...

Note : All pictures of this site are copyrighted.
You don't have to use it without my consent.

depuis le 28jan2008