OpenVMS VAXLIBR01_072 OpenVMS VAX V7.2 LIBRTL ECO Summary

TITLE: OpenVMS VAXLIBR01_072 OpenVMS VAX V7.2 LIBRTL ECO Summary
 
Modification Date:  03-NOV-1999
Modification Type:  New Kit

NOTE:  An OpenVMS saveset or PCSI installation file is stored
       on the Internet in a self-expanding compressed file.
       The name of the compressed file will be kit_name-dcx_vaxexe
       for OpenVMS VAX or kit_name-dcx_axpexe for OpenVMS Alpha.
 
       Once the file is copied to your system, it can be expanded
       by typing RUN compressed_file.  The resultant file will
       be the OpenVMS saveset or PCSI installation file which
       can be used to install the ECO.
 
Copyright (c) Compaq Computer Corporation 1999.  All rights reserved.

OP/SYS:     OpenVMS VAX

COMPONENT:  LIBRTL

SOURCE:     Compaq Computer Corporation

ECO INFORMATION:

     ECO Kit Name:  VAXLIBR01_072
     ECO Kits Superseded by This ECO Kit:  None 
     ECO Kit Approximate Size:  1116 Blocks
                    Saveset A - 1116 Blocks

     Kit Applies To:  OpenVMS VAX V7.2
     System/Cluster Reboot Necessary:  Yes
     Rolling Re-boot Supported:  Yes
     Installation Rating:  INSTALL_3
                            3 - To be installed on all systems running
                                the listed versions of OpenVMS which
                                are experiencing the problems described.}
     Kit Dependencies:

       The following remedial kit(s) must be installed BEFORE
       installation of this kit:

         None

       In order to receive all the corrections listed in this
       kit, the following remedial kits should also be installed:

         None


ECO KIT SUMMARY:

An ECO kit exists for OpenVMS VAX V7.2.  This kit addresses the following
problems: 

PROBLEMS ADDRESSED IN VAXLIBR01_072 KIT

     o  C compiler generates incorrectly optimized code

          The source for LIB$VM_MALLOC (LIBMALLOC.C)  is  compiled  with
          the  DEC  C  V5.2-003  compiler.   This  compiler can generate
          incorrectly optimized code for a _REMQHI builtin.




          Since incorrectly optimized code was generated for the _REMQHI
          builtin,  LIB$VM_MALLOC used an incorrect address for a memory
          block.  This problem in turn,  caused  LIB$VM_MALLOC  to  loop
          indefinitely trying find a particular memory block.

          The LIBRTL routine LIB$VM_MALLOC is used  by  the  DEC  C  RTL
          routine  "malloc"  to  allocate  memory.  LIB$VM_MALLOC uses a
          series of queues to manage blocks of memory of various sizes.

          When memory is requested and a block of the required  size  is
          not immediately available, LIB$VM_MALLOC may try to expand the
          P0 region using $EXPREG.  If this attempt fails, LIB$VM_MALLOC
          will  try to break up larger blocks of free memory, then merge
          smaller blocks.  This problem  occurs  when  trying  to  merge
          smaller  blocks and LIB$VM_MALLOC loops indefinitely searching
          for a block.

          A  workaround  involved  declaring  the  affected  pointer  as
          "volatile".    This  caused  the  compiler  to  generate  less
          optimized, but correct code.


INSTALLATION NOTES:

Install this kit with the VMSINSTAL utility  by  logging  into  the
SYSTEM account, and typing the following at the DCL prompt:

     @SYS$UPDATE:VMSINSTAL VAXLIBR01_072 [location of the saveset]

The saveset location may be a tape drive, CD, or a  disk  directory
that contains the kit saveset.

The images in this kit will not take effect  until  the  system  is
rebooted.

If you have other nodes in your OpenVMS cluster, they must also  be
rebooted  in  order  to make use of the new image(s).  If it is not
possible or convenient to reboot the entire cluster at this time, a
rolling re-boot may be performed.

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vaxlibr01_072.README
vaxlibr01_072.CHKSUM
vaxlibr01_072.CVRLET_TXT
vaxlibr01_072.a-dcx_vaxexe
vaxlibr01_072.CVRLET_TXT