From: Olaf Barthel To: Subject: Re: [TA] AmigaOS 3.5 For Olaf Date: 30 April 1999 17:23 On Apr 30 Philippe (Philippe FERRUCCI) wrote: > > Should the programs we've got now (Diavolo, DiskSalv etc..) > >still be able to do their jobs if their authors don't update them for > >OS3.5? > Sure ! ROM is not updated. So compatibility is at 100%. Right Olaf ? Well... I wish I could give you a definite "Yes", but as recent research has has revealed, 100% cannot be attained. You practically never get 100% unless you leave things as they are. And we don't want that to happen, do we? This is a really tricky issue and we're not the first to experience this: back when AmigaOS 2.0 was developed, the operating system development group at Commodore had their share of trouble with software that didn't expect things to change. For example, software didn't expect the CPU type to change (delay loops failed on faster machines, certain instructions crashed faster machines, the fact that addresses were suddenly 32 bits wide instead of 24 caused bizarre crashes, etc.), didn't expect the amount and type of memory to change (expanded memory was not accepted/detected/used, data that should have gone into chip RAM ended up in fast RAM, etc.) or didn't expect "observed" and undocumented operating system behaviour to change (register configurations, register side-effects, memory layout of data structures). While I'm glad that we won't face the same problems again, we face different problems that are not entirely unrelated to them: software and hardware that was not designed to adapt to changes. For example, there is still a lot of old RTG software in use. And by old I mean the Picasso II software, EGS, Merlin, Domino, oMnibus, Retina, Retina Z3 and even the earliest CyberGraphics stuff. While some of this software was updated or made obsolete by subsequent developments (e.g. you can use your Merlin and oMnibus cards with Picasso96), some potential customers are still using the old code. While I wish that one could coax these people to upgrade their old software, you cannot depend upon it. This is where things get really, really tough since virtually all old RTG software suffers from severe quality problems. For example, some of the RTG code is "hardwired" to support certain "exotic" operating system features that were used only in a particular context and in a particular sequence. Change the context or change the sequence and you'll crash the machine. I daresay that if RTG would have been part of the OS 3.5 update, it would have made our lives quite a bit easier... -- Home: Olaf Barthel, Brabeckstrasse 35, D-30559 Hannover Net: olsen@sourcery.han.de