How is shared memory address range determined

Article View: comp.sys.hp.hpux

Article #73

#73

From: Patrick Coghlan
Date: Fri, 22 Apr 1994 16:34

8 lines
1325 bytes

I notice that under HP-UX, processes that attach a region of shared
memory end up with it at the same virtual address.

How does UNIX manage to do this?  Does it preallocate virtual address
space for (max # of shared regions) regions of size (maximum region size)?
Then, use the key provided by the user to map him into a specific range
of virtual addresses (i.e. all users with the same key map into the same
address range)?

Technical Details

Message-ID: <1994Apr22.163441.19924@bcarh54a.bnr.ca>

Path:

arc1-ca.pugleaf.net!gmd.de!nntp.gmd.de!xlink.net!howland.reston.ans.net!wupost!news.utdallas.edu!corpgate!bnrgate!bmerha64.bnr.ca!bcars267!bcarh54a!bcarh5f8!coghlan

Show Full Headers

Complete Article Headers

X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 14b500,89dc02a43cbd3d6f,start
X-Google-Attributes: gid14b500,public
X-Google-Thread: fc89c,89dc02a43cbd3d6f,start
X-Google-Attributes: gidfc89c,public
X-Google-Thread: fcda7,89dc02a43cbd3d6f,start
X-Google-Attributes: gidfcda7,public
X-Google-ArrivalTime: 1994-04-25 09:39:57 PST
Newsgroups: comp.sys.hp.hpux,comp.unix.programmer,bnr.unix
Path: arc1-ca.pugleaf.net!gmd.de!nntp.gmd.de!xlink.net!howland.reston.ans.net!wupost!news.utdallas.edu!corpgate!bnrgate!bmerha64.bnr.ca!bcars267!bcarh54a!bcarh5f8!coghlan
From: coghlan@bcarh5f8.bnr.ca (Patrick Coghlan)
Subject: How is shared memory address range determined
Message-ID: <1994Apr22.163441.19924@bcarh54a.bnr.ca>
Sender: coghlan@bcarh5f8 (Patrick Coghlan)
Date: Fri, 22 Apr 1994 16:34:41 GMT
Nntp-Posting-Host: bcarh5f8
Organization: Bell-Northern Research, Ottawa, Canada
Lines: 8