BSD 2.11 - man page for phys (bsd section 2)
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phys - allow a process to access physical addresses (2BSD)
phys(segreg, size, physaddr)
unsigned int segreg, size, physaddr;
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
This call may only be executed by the super-user.
[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.
PDP-11 segmentation hardware
On systems with ENABLE/34(tm) memory mapping boards, phys cannot be used to map in the I/O
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.
3rd Berkeley Distribution January 22, 1987 PHYS(2)
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