Scott Robison wrote: > On Sat, Jan 16, 2016 at 1:58 PM, James K. Lowden <jklowden at schemamania.org> > wrote: > >> On Fri, 15 Jan 2016 21:41:41 -0500 >> Richard Damon <Richard at Damon-Family.org> wrote: >> >>> there are machines where it doesn't work (you just need a larger >>> program space than data space). >> >> Huh. An example of which is the "medium model" of the Intel 8086: >> 20-bit code pointers and 16-bit data pointers. A machine for which C >> compilers existed, and on which no Posix system will ever run (because >> it lacks an MMU). Thanks for that. >> > > Sorry for the OT diversion, but I'm just curious as I don't have historical > POSIX standards for reference. Does POSIX really *require* an MMU? > Certainly Unix like systems were written for 8086 class computers, but > given that POSIX was first standardized in 1988 I'm just curious as to > whether or not an MMU is a requirement or just really nice to have.
ST-Minix ran on MC68000 - no MMU. POSIX API only defines a programming model, it doesn't mandate how it gets implemented under the covers. An MMU *can* make some things easier, but we had fork/exec etc. even without it. -- -- Howard Chu CTO, Symas Corp. http://www.symas.com Director, Highland Sun http://highlandsun.com/hyc/ Chief Architect, OpenLDAP http://www.openldap.org/project/
