Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site mprvaxa.UUCP Path: utzoo!linus!decvax!microsoft!uw-beaver!ubc-visi!mprvaxa!tbray From: tbray@mprvaxa Newsgroups: net.unix-wizards Subject: Re: Shared system routines Message-ID: <244@mprvaxa.UUCP> Date: Tue, 26-Jul-83 11:49:53 EDT Article-I.D.: mprvaxa.244 Posted: Tue Jul 26 11:49:53 1983 Date-Received: Wed, 27-Jul-83 13:06:24 EDT Organization: Microtel Pacific Research, Burnaby BC Lines: 20 Shared system routines were a primary design objective of VMS, and several different tools are provided for building and using them. However, the goal was not easily achieved, and even now, 5 years later, there were some pretty fundamental changes made to the linker (read loader) with VMS version 3, to eliminate some obscure contradictions that had been introduced. People in the group are correct when they predict horrible problems arising in making the loader smart enough to correctly all the permutations and combinations this can introduce. And with real memory getting so cheap, I wonder if it's worth it. The way it's done at VMS run-time is that the shared stuff can appear anywhere in the address space, with the corresponding entries in the page table containing a flag indicating a shared reference. The code is then found via ANOTHER page table (called a global section table). This is referred to as a 'global valid page fault'. thinking that the new Amdahls support 64M phys memory (!!!!!!!), ...microsoft!ubc-visi!mprvaxa!tbray