1PHYS(2)                       System Calls Manual                      PHYS(2)
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NAME

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

9       phys(segreg, size, physaddr)
10       unsigned int segreg, size, physaddr;
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DESCRIPTION

13       The  argument  segreg  specifies a process virtual (data-space) address
14       range of 8K bytes starting at virtual address  segreg×8K  bytes.   This
15       address  range is mapped into physical address physaddr×64 bytes.  Only
16       the first size×64 bytes of this mapping is  addressable.   If  size  is
17       zero,  any previous mapping of this virtual address range is nullified.
18       For example, the call
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20            phys(7, 1, 0177775);
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22       will map virtual  addresses  0160000-0160077  into  physical  addresses
23       017777500-017777577.   In  particular,  virtual  address 0160060 is the
24       PDP-11 console located at physical address 017777560.
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26       This call may only be executed by the super-user.
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ERRORS

29       [EPERM]        The process's effective user ID is not the super-user.
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31       [EINVAL]       Segreg is less than 0 or greater than 7.
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33       [EINVAL]       Size is less than 0 or greater than 128.
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SEE ALSO

36       PDP-11 segmentation hardware
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BUGS

39       On systems with ENABLE/34(tm) memory mapping  boards,  phys  cannot  be
40       used to map in the I/O page.
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42       This  system  call is very dangerous.  It is not considered a permanent
43       part of the system.
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45       Phys is unique to the PDP-11 and 2BSD; its use is discouraged.
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493rd Berkeley Distribution      January 22, 1987                        PHYS(2)