Re: NetBSD without MMU ?
David Laight <[email protected]>
| Newsgroups | gmane.os.netbsd.devel.ports |
|---|---|
| Message-ID | <[email protected]> |
On Fri, Apr 12, 2002 at 11:35:39AM -0700, Byan, Stephen wrote: > > BTW, the PDP-11/20 and PDP-11/40 didn't have memory mappers; that was an > option for the PDP-11/45. IIRC the pdp 11/40 did have an MMU - used to expand the 16bit virtual address out to the wider physical bus. RSX/11M used the MMU to swap processes into different physical addresses, some programs (eg the task builder aka linker) used it to get their resident size above 64kb - useful for linking moderate sized programs, but had to be restricted to use less that all the available memory for very large ones. RSX/11M didn't page - only swapped, indeed (from experiments putting all the swap space onto an 8" floppy drive) might have swapped synchronously! Neither the 11/10 nor the 11/03 had an MMU. David -- David Laight: [email protected]