Download the free 64 Bit Alpha Oberon System Evaluation Kit for HP OpenVMS Alpha

Description of the components

• AlphaOberon System (AOS); fully functional.
• AlphaOberon-2 Compiler (A2O); the compiler included in the free AOS evaluation kit limits the number of imported modules and restricts the source code size. The A2O User's Guide is here.
• The Oberon-2 Language Report (only 24 pages! - incl. syntax diagrams and examples)

Requirements

AlphaOberon uses 64 bit memory (VLM) under OpenVMS Alpha 7.x and later to exploit the 64 bit address space¹; pointers and integers have 64 bit size.

For more details, see What is a 64 bit compiler?
To get the binary distribution kit CD of OpenVMS v8.3 with many layered products and free product authorization keys (OpenVMS, DecWindows/Motif, ...) for private use, follow the links to OpenVMS Hobbyists at the bottom of this page.

Legal

Copyright (C) 1994 by ETH Zurich, Institute for Computer Systems.
Incorporates changes and extensions made by the Institut fuer Praktische Informatik, Gruppe fuer Systemsoftware, Universitaet Linz.
Copyright (1996-1999) Implementation for OpenVMS Alpha by modulAware.

Permission to use, copy, modify and distribute this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that neither the name of ETH, nor the name University Linz, nor the name modulAware is used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. Neither ETH, nor University Linz, nor modulAware make any representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty.

ETH, AND University Linz, AND modulAware DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ETH or University Linz OR modulAware BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Download

1. AlphaOberon base system with Tetris (Obtris) game and TrapDemo (size about 1.2MB)

2. AlphaOberon online documentation plus more applications and games (optional, size about 1.1MB)

3. AlphaOberon screen and printer fonts (optional, size 300KB)

Installation

Install the Unzip as a foreign command using the command

$ unzip :== $device:[dir]UNZIP.EXE

$ unzip aose.zip
$ unzip aose1.zip ! optional
$ unzip aose2.zip ! optional

$ set default [.aose]
$ @setup.com

$ Oberon
$! or in order to use VLM under OpenVMS Alpha 7.0 use
$ Oberon/pointersize=64/heap=10

To start Obtris, an Oberon-2 implementation of the famous Tetris game

1. move the mouse pointer to the pop-up menu called "Tools" (marked in light blue color),
2. press and hold the middle mouse key,
3. move the pointer to the menu entry "System.Open Obtris.Tool" and
4. release the middle mouse key. This will open a viewer called "Obtris.Tool".
5. Move the pointer to the text "Obtris.Open" in this viewer and middle-click. This will open a new viewer on the left-hand side.
6. Move the pointer to the pop-up menu "Start" in the header-line of the Obtris viewer and middle-click.
7. Now play using the cursor keys and "space" to drop the objects.
8. To interrupt the game, press "p" on the keyboard.
9. You can later resume the game using "Start" menu.
10. To read the Obtris instructions, middle-click on the text "Edit.Open" in the Obtris tools window.
11. To leave the Oberon System, middle-click on the text System.Quit.

To compile the Oberon-2 example TrapDemo

1. Select the beginning of the file name string "TrapDemo.Mod" in the System.Tool viewer, by moving the cursor over the "T" of this string and click the right mouse button.
2. Move the mouse over the string "XE.Open" and click with the middle mouse button. This opens a new viewer on the left hand site, called TrapDemo.Mod.
3. Move the mouse over the string Compiler.Compile in the last source line of the TrapDemo source file and click on this command. This starts the AlphaOberon-2 compiler.
4. After the System.log viewer displays "ok", click on the string "TrapDemo.Trap". This displays a string and some numbers in System.log and then opens a new viewer System.Trap because TrapDemo causes an integer overflow. The trap-viewer contains the invocation contexts of the recursively called procedures "TrapDemo.Q". The most recent invocation is on the top.
5. You can scroll in the trap-viewer by clicking with the left mouse button in the scroll bar.

To try the SortPlus demo

Third Parties' Copy-right and -left

Getting started with Oberon

Commands are parameterless procedures which may be executed directly from the operating system interface. Procedures from anywhere in a module hierarchy may be called in this way and there is no need for a "top" module which distributes commands to other modules. Instead, command distribution is built into the operating system. When a command terminates, control is passed back to the operating system's main loop. However, the module that contained the last command remains loaded in the system and all of its global variables remain unaltered. Subsequent commands may reference these variables freely.

The granularity of commands may be quite fine. Typical commands display the directory of a storage device, increase the font size of the text last selected or compile the contents of the active window. A user may execute commands in any sequence and may thus be working on completely different problems in different windows at the same time. We call this "one-process multitasking".

Using Commands

The system will then attempt to interpret the text that is pointed at as "Modulename.Commandname" and search for the corresponding module, possibly loading it from disk if it cannot be found in memory. If the module is present or can be loaded, it will then search for the requested command and execute it. If the module or the command cannot be found, the system will simply resume its previous state.

For example, when you click with the middle mouse button on the string "System.Time" displayed in a text viewer, this command will display the current time in the viewer called System.Log, i.e., the window in the upper right corner.

Extensibility