Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!ucsd!ucsdhub!hp-sdd!apollo!weber_w
From: weber_w@apollo.HP.COM (Walt Weber)
Newsgroups: comp.sys.apollo
Subject: Re:  sr9 to sr10
Message-ID: <490552bc.20b6d@apollo.HP.COM>
Date: 6 Mar 90 00:01:00 GMT
References: <9003051659.AA24525@richter.mit.edu>
Sender: root@apollo.HP.COM
Reply-To: weber_w@apollo.HP.COM (Walt Weber)
Organization: Hewlett Packard NARC @ Apollo Systems Division
Lines: 39

In article <9003051659.AA24525@richter.mit.edu> krowitz%richter@UMIX.CC.UMICH.EDU (David Krowitz) writes:
>SR10 is "Just Like Real Unix" (JLRU) ... all memory space which
>is declared by the program is allocated as soon as the program is
>started, even if the memory is never actually used during the
>execution. Under SR9, memory was allocated in the Aegis style --
>...
>There is an undocumented and unsupported switch for /com/bind which
>causes and SR10 program to use SR9 Aegis style memory allocation.

The following is an excerpt from the upcoming documentation of the
UNSUPPORTED bind option which has been widely discussed here.  (Note that
this is still unsupported, until the revision is released.  And no, I
**don't** have a date or a revision number.  :-)

 0.1.4 New /com/bind Option: -sparse_vm     

 The  /com/bind option -sparse_vm provides compatibility with one kind of SR9.7
 behavior.  At SR9.7, all virtual memory had virtual  address  space  allocated
 at   creation,  but  not  disk  space.   Instead,  disk  space  was  allocated
 dynamically.  At SR10, all virtual memory had both virtual address  space  and
 disk  space  allocated  at  creation.   This change was made for compatibility
 with UNIX, where applications do not expect to run out of disk space. 

 The  new  option,  -sparse_vm,  enables  the  SR9.7  dynamic  disk  allocation
 behavior for programs run on sr10.2 or a later release.   Currently,  the  new
 behavior  affects  only  the break area, which includes the .bss area and that
 used by malloc(); it does  not  affect  memory  allocation  for  rws_$  calls.
 Also,  the  -sparse_vm  option  must not be used with C programs that make the
 fork() system call, because child processes will not have their  own  distinct
 break area.  These restrictions may be removed at a future release. 
-------

>krowitz@richter.mit.edu   (18.83.0.109)

...walt...
Walt Weber               Hewlett Packard NARC @ Apollo Systems Division
-The views expressed herein are personal, and not binding on ANYONE-
   "The power of accurate observation is commonly called cynicism
    by those who have not got it" -George Bernard Shaw