Rational/R1000s400

History

The Rational R1000/s400 is the final and smallest member of the worlds probably first only and last "Ada-only" Computer.

Rational set out to build an integrated development environment, and found out that contemporary (early 1980ies) computers could simply not execute it fast enough, to make it attractive in the marketplace, so they built their own computer to execute Ada and the Environment, and only that.

The R1000, which is functionally unchanged through the four series, is a stack based architecture inspired in part by the Burroughs 6700, but focused entirely on the data model and tasking model of Ada, so that for instance the notoriously difficult to implement Ada Rendez-Vous mechanism executes in a single instruction.

Terma, a danish aerospace manufacturer, donated their last Rational R1000 s400 computer to us in 2009, including its original shipping crate in nearly spotless condition, along with 1.5 meter of manuals, and blank disk drives, but no software at all, because its classified past required it to be "sterilized".

Software, and another machine and various spare parts, were donated to us in 2019 by Pierre-Alain Muller, presently Vice-President of Université Haute Alsace, but previously responsible for Rationals European support organization.

Hardware Architecture

Considering the size, there is a surprising amount of hardware packed into the cabinet:

     Ethernet    ┍━━━━━━━━━━━━━┯━━━━━━━━━━━━━━━━━━━━━━━━━━━┯━━━━━━━━━━━━━┯━━━━━━━━━━━━━┑         72 VAL+PARITY
      TCP/IP     │             │                           │             │             │
        │        │ ┍━━━━━━━━━━━━━━━━━━━━━━━━━━━┯━━━━━━━━━━━━━┯━━━━━━━━━━━━━┯━━━━━━━━━━━━━┑       72 TYP+PARITY
   ┌────┴────┐   │ │           │               │           │ │           │ │           │ │
   │         │   │ │           │   ┍━━━━━━━━━━━━━┯━━━━━━━━━━━━━┯━━━━━━━━━━━━━┑         │ │       72 FIU+PARITY
   │ CMC/ENP │   │ │           │   │           │ │         │ │ │         │ │ │         │ │
   │         │   │ │ ┍━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┑      9 CHECK BITS
   └────┰────┘   │ │ │         │   │           │ │         │ │ │         │ │ │         │ │ │
        ┃        │ │ │ ┍━━━━━━━━━━━━━┯━━━━━━━━━━━━━┯━━━━━━━━━━━━━┯━━━━━━━━━━━━━━━┯━━━━━━━━━━━┑    9 CONTROL
        ┃        │ │ │ │       │   │ │         │ │ │       │ │ │ │       │ │ │   │     │ │ │ │
   ┌────┸────┐ ┌─┴─┴─┴─┴─┐ ┌───┴───┴─┴─┐ ┌─────┴─┴─┴─┐ ┌───┴─┴─┴─┴─┐ ┌───┴─┴─┴───┴─┐ ┌─┴─┴─┴─┴─┐  ↑FOREPLANE↑
   │         │ │         │ │           │ │           │ │           │ │             │ │         │
   │  RESHA  ╞═╡   IOC   │ │    VAL    │ │    TYP    │ │    SEQ    │ │     FIU     │ │ MEM × 2 │
   │         │ │         │ │           │ │           │ │           │ │             │ │         │
   └┬─┬─┬─┬─┬┘ └┬─┬─┬─┬─┬┘ └┬─┬─┬─┬─┬─┬┘ └┬─┬─┬─┬─┬─┬┘ └┬─┬─┬─┬─┬─┬┘ └┬─┬─┬─┬─┬─┬─┬┘ └┬─┬─┬─┬─┬┘  ↓BACKPLANE↓
    │ │ │ │ │   │ │ │ │ │   │ │ │ │ │ │   │ │ │ │ │ │   │ │ │ │ │ │   │ │ │ │ │ │ │   │ │ │ │ │
    │ │ │ │ │   ┕━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━┙ │ │ │ ┕━━━━━━━━━━━━━┙ │  15 UADDR / 10 MEMCTL
    │ │ │ │ │     │ │ │ │     │ │ │ │ │     │ │ │ │ │     │ │ │ │ │     │ │ │   │ │   │ │ │   │
    I/O ports     │ │ │ │     ┕━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━┙ │ │   │  76 ADDRESS
    │ │ │ │ │     │ │ │ │       │ │ │ │       │ │ │ │       │ │ │ │       │ │   │ │     │ │   │
    SCSI - disk   ┕━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━┙ │   │   3 CLOCKS
    SCSI - tape     │ │ │         │ │ │         │ │ │         │ │ │         │   │ │       │   │
    Phone           ┕━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━┙   │   2 DIAGS
    Console           │ │           │ │           │ │           │ │             │ │           │
    Serial port       ┕━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━━━┙ │           │  12 CONDITIONS
    Ethernet (cluster)  │             │             │             │               │           │
                        ┕━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━┷━━━━━━━━━━━━━━━┷━━━━━━━━━━━┙  64 POWER

The main processor consists of the VAL(ue), TYP(e), SEQ(uencer) and F(ield)I(solation)Unit, each occupying a printed circuit board a half meter on both sides.

The I(nput)O(utput)C(contoller) is that, but it is also a computer in it's own right, a 68K20 running an operating system with a file system, a command line shell, utility programs etc.

The (R)ational E(thernet) S(csi) H(ost) Adapter) is basically a large printed circuit board with all the I/O devices which did not fit on the IOC, to which it is connected by the "normal" 68k bus from the IOC.

The "CMC/ENP" is a 3rd party 68K20 VME board which runs the TCP/IP stack.

The s100 model

The first version of the R1000 was the s100 model, which was a four processor machine.

Michael Druke has kindly shared these pictures of the s100 back-plane he has saved in his basement:

Each of the four CPUs would also have a front-plane spanning just the cards of that CPU.

Each CPU consists of "SYS", "VAL", "TYP", "SEQ", "FIU" and from one to four "MEM" boards. At far left (when seen from the back) four slots named I0…I3 contain cards which connect the CPUs to the PDP-11 I/O processor in another rack.

In total the backplane has 40x360 = 14400 pins for all the cards.

The square metal blocks at the bottom connects to the power supplies which delivers more than 5 kW of power at 5 Volt.