@ Joerg Straube Interesting, thanks. I wasn't aware of the 89 version so far. I assume you have seen the section "Differences between Oberon and Revised Oberon" on page 10 in the first paper in the referenced document. I've not seen such a section for Oberon 90. Do we actually have access to the source code of the earlier versions of the Oberon System, especially the one referred to by the 1988 paper (see https://doi.org/10.3929/ethz-a-000487176, presumably written in Obern 87), and the one which was released in 1989 (see https://dl.acm.org/doi/10.1145/1238844.1411838, presumably written in Oberon 89), and the first version used for courses in 1990 (presumably written in Oberon 90)? Best R. _______________________________ From: Joerg Sent on: Sat, 04 Jan 2020 22:20:04 +0100 To: ETH Oberon and related systems Cc: Subject: Re: [Oberon] 30th anniversary of Oberon Here is the language report of Oberon89 https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/68899/eth-3205-01.pdf?sequence=1&isAllowed=y No DEFINITION nor IMPLEMENTATION. Very close to Oberon90. BYTE is still in the language not in SYSTEM yet. br Jörg