[comp.os.vms] Booting VAX with 96 megabytes

pung@ornl-ncc ("M. S. Pung") (01/11/88)

Hi,
	The following attached message describes a problem that was
	discovered recently at our site.

	I thought I would pass it on to the net.

	Has anyone seen this problem at their site or know a work
	around to it ???

	Note that I have not tested out what the user site suggests in
	the following message, so I do not know if it works or not....

	One note, the folks at Colorado mentioned the fact that the
	problem may be fixed in V4.7, but if the problem is really in
	VMB.EXE, I dont see how a VMS upgrade will fix it since VMB.EXE
	resides on the PRO 380 console hard disk..???

	Thanks in advance to all who reply.


	|------------------------------------------------------------------|
	|          Mike Pung               |	   (615) 574-8082          |
	|     Oak Ridge National Lab       | Pung%ornl-knsms@ornl-msr.arpa |
	|  Martin Marietta Energy Systems  |        128.219.128.10	   |
	|------------------------------------------------------------------|









                   I N T E R O F F I C E   M E M O R A N D U M


Date:      6-Jan-1988 02:15pm EST
Subject:   VAX 8700/8550 Memory BUG




			   ** Notice **

	A problem occurs when attempting to boot a VAX 8550/8700/8800 series 
        computer with exactly 96 megabytes of memory.  Listed below are the 
        error messages that result when attempting to boot a system configured 
        with the "magic" amount of memory.  Interesting of note is the fact 
        that that VAX 8550 and VAX 8700 produce different error messages.

	Note that the problem only occurs if you attempt to boot with exactly 
        96 megabytes of memory, the problem does not occur for example if you 
        boot with 80 megabytes or 128 megabytes.


	On a VAX 8550, the error message displayed is the following:
	   "SYSBOOT-E-IOERROR, I/O error reading DUDRIVER.EXE"

	On a VAX 8700, the error message displayed is the following:
	   "SYSTEM-F-MACHINECHECK, Unexpeted Machine Check"

	After calling the DEC Software Support Center, the response was that
	this was a known problem and that it already had been reported by many 
        sites.  They said that it was a problem in VMB.EXE but that it was not 
        known exactly what the problem is or how to fix it.  They said it may 
        be fixed in V4.7 but then again maybe not...

	There was one fix suggested by a user site as something that may 
        get around the problem.  Set the PHYSICALPAGES sysgen parameter to the 
        value 195584, and supposedly this will allow the system to boot with 
        96 megabytes of memory; however only 95.5 megabytes are mapped by 
        VAX/VMS.  Note that this is not a DEC patch but something that was 
        tried and suggested by an end user site.

							Mike Pung
------

RAY@CRVAX.SRI.COM (Ramon M. Curiel) (01/14/88)

Version 4.7 includes a new copy of the VMB.EXE to fix at least part of
these problems.  The release notes allude to problems on the 8700 and
8500 having problems of this type.

Ray