PHYS(2)             UNIX Programmer's Manual		  PHYS(2)


NAME
     phys - allow a process to access physical addresses (2BSD)

SYNOPSIS
     phys(segreg, size, physaddr)
     unsigned int segreg, size, physaddr;

DESCRIPTION
     The argument segreg specifies a process virtual (data-space)
     address range of 8K bytes starting at virtual address
     segregx8K bytes.  This address range is mapped into physical
     address physaddrx64 bytes.  Only the first sizex64 bytes of
     this mapping is addressable.  If size is zero, any previous
     mapping of this virtual address range is nullified.  For
     example, the call

	  phys(7, 1, 0177775);

     will map virtual addresses 0160000-0160077 into physical
     addresses 017777500-017777577.  In particular, virtual
     address 0160060 is the PDP-11 console located at physical
     address 017777560.

     This call may only be executed by the super-user.

ERRORS
     [EPERM]	    The process's effective user ID is not the
		    super-user.

     [EINVAL]	    Segreg is less than 0 or greater than 7.

     [EINVAL]	    Size is less than 0 or greater than 128.

SEE ALSO
     PDP-11 segmentation hardware

BUGS
     On systems with ENABLE/34(tm) memory mapping boards, phys
     cannot be used to map in the I/O page.

     This system call is very dangerous.  It is not considered a
     permanent part of the system.

     Phys is unique to the PDP-11 and 2BSD; its use is
     discouraged.


Printed 11/26/99	January 22, 1987			1


 
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