ingoldsby@calgary.UUCP (07/09/86)
I have a question for the OS9 gurus out there: How does OS9 Level II cope with the 64K address space limit of the 6809? I know that it functions on systems with well over 64K, 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
dibble@rochester.UUCP (07/13/86)
> 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