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Path: utzoo!utcs!mnetor!seismo!rochester!dibble
From: dibble@rochester.UUCP
Newsgroups: net.micro.6809
Subject: Re: OS9 Level II program size
Message-ID: <19374@rochester.ARPA>
Date: Sat, 12-Jul-86 23:23:46 EDT
Article-I.D.: rocheste.19374
Posted: Sat Jul 12 23:23:46 1986
Date-Received: Sun, 13-Jul-86 04:59:08 EDT
References: <247@vaxb.calgary.UUCP>
Organization: U of Rochester, CS Dept., Rochester, NY
Lines: 19
Keywords: OS9
Summary: OS-9 Level Two DAT

> How does OS9 Level II
> cope with the 64K address space limit of the 6809?  
>  but can individual programs
> be larger than 64K.  While I'm on the subject of OS9, does OS9/68K
> also use position independent code for its modules?
> 
> 		Terry Ingoldsby

OS-9 Level Two uses a DAT (Dynamic Address  Translator) to map the 64K
address space of the 6809 into whatever memory the system has.  Each 
_task_ can see one 64K address space at a time.  Modules can be in any
number of address spaces at the same time.  There are lots of tricks for 
using more than 64K at a time.  All the tricks turn on splitting the program
into several tasks, each with up to 64K, or swapping pages between address
spaces.

OS9/68K requires position independent code.

Peter Dibble