1.1. Objectives

A first objective of this project was to perform validation, performance and robustness testing of the TenDRA technology to ensure its capability to implement and fully bootstrap a UNIX-like operating system on a variety of target processor architectures.

Another objective was to provide an assessment of TenDRA technology to express a fully portable operating system implementation.

This report summarizes the work done with respect to these two objectives.

1.2. General description

A Unix system can be divided into three parts, which characterize the portability level of the code:

• The Kernel, which has some parts in assembler, e.g. for context switching, interruptions, locks, or parts of device drivers. Assembly code is used either in separate files or is embedded in C programs or header files.

• The Libraries, some of which may contain assembly code. The crt0 library and code for system calls are examples.

• The Commands, in which use of assembly code is very unusual. They share a non-explicit API with the libraries against which they are built.

As for other software OSF already ported to ANDF, the port of the Unix system has been done in three successive steps:

• The NAT-NAT step, which consists in rebuilding the system with the native compilation chain, to ensure that the system can be regenerated from the set of sources.

• The DRA-NAT step, for which the TenDRA technology is employed as a replacement of the native compilation chain to build the system, using the native system header files, as for a classical compilation chain. This part involves dealing with assembler issues as well as discrepancies between the native and the TenDRA code generators. Note that Unix systems are known to be compiler dependent.

• The DRA-DRA step, which consists in using the TenDRA technology as a portability tool. The API shared by the commands and libraries has to be defined, and used to produce architecture independent ANDF code for these parts. This code is then installed and validated on the selected machines. Note that the kernel part of the Unix system has not been included in this task since it is essentially not portable.

1.3. Choice of a UNIX system and update of the objectives

We have used the source for the UnixWare system as the base for performing the port of a Unix source code. We originally planned to conduct the experiment on two different platforms: an Intel/386 platform and a Sun/Sparc one. The NAT-NAT, DRA-NAT and part of the DRA-DRA steps have been achieved on the Intel/386 platform. Then, in the light of the experience we gained from this work, we decided to re-focus the project on a more complete DRA-DRA experiment, with a different Unix system. This report only covers that part of the work done up to this change.

1.4. Choice of the validation tools

Throughout this experiment we had to validate the various parts of the system we built.

A first level of validation was achieved by using the kernel and commands built in the DRA-NAT step for our daily work. In addition, we used the VSX4 and AIMIII validation suites to test more thoroughly the robustness and performance of the system built in DRA-NAT mode.