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Note 38.0 DECnet Down-line Loading No replies
FURILO::GIORGETTI 529 lines 4-SEP-1985 15:54
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+---------------+ +-----------------+
| d i g i t a l | | uNOTE # 038 |
+---------------+ +-----------------+
+----------------------------------------------------+-----------------+
| Title: DECnet Down-line Loading | Date: 26-Jul-85 |
+----------------------------------------------------+-----------------+
| Originator: Scott D. Blessley | Page 1 of 9 |
+----------------------------------------------------+-----------------+
This article overviews the downline load process used by DECnet for
remote loading of PDP-11 and VAX processors. Downline loading is a
versatile and complicated process. This article is intended as an
introduction/aid to the process, not a tutorial. An extensive reference
list appears at the end of the article for readers interested in
pursuing the subject further.
1 OVERVIEW OF THE DOWNLINE LOAD PROCESS
DECnet downline load is the set of hardware and software features which
allow complete systems (RSX-11S and VAXELN) to be loaded into remote,
potentially unattended processors. In addition, RSX-11S offers the
capability to: dynamically load tasks over comm lines, checkpoint tasks
out of memory over the line, and upline dump a failed operating system.
RSX-11S functionality is a subset of those features found in RSX-11M.
VAXELN also features a symbolic debugger that allows debug of the target
from the host processor.
2 DEFINITIONS
2.1 HOST
The host [node] (for this discussion) refers to both the machine which
originates the load, as well as the machine which loads the software.
In actuality, these need not be the same machine.
2.2 TARGET
The target [node] is the machine being loaded with new software. It
must be powered up, but may or may not have to be awaiting primary
bootstrap, depending on its communications bootstrap device and boot
options.
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2.3 EXECUTOR
The executor [node] is the node which initiates the commands to downline
load a target. It need not be the same as the host.
+------------+
| |
| TARGET |<----------+
| (HOBSON::) | |
+------------+ |
^ | |
Operating System | | Load request |
| | |
| | |
| | |
| | | NCP>TRIGGER NODE HOBSON
| v v
+------------+ +------------+
| | | |
| HOST | | EXECUTOR |
| (FURILO::) | | (FURILO::) |
+------------+ +------------+
( ^ same CPU or ^
different)
Relationship between host, target, and executor nodes
3 PREPARING FOR DOWNLINE LOAD
There are three overall steps:
o Configuring the communications hardware - both on the host and
target systems
o Configuring the DECnet software and the operating system image that
will be loaded.
o Verification and testing.
The most frequent problem is the failure to correctly configure the host
and/or target hardware. There are two principal places for error:
- setting DIP switches inappropriately resulting in incorrect line
speeds, wrong power-up boot options (BSEL switches), etc.
- Skew between hardware configuration and software (for example
mis-specifying the vector/CSR or the Ethernet address for the target
device). Be sure to have the latest version of the hardware
manuals.
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Specific points to be careful about:
1. Vector/CSR
2. B[oot]SEL[ect] switches - these specify under what conditions the
comm interface will force a bootstrap.
3. Service password - this is a protection feature to lessen the
likelihood of an inadvertent or malicious downline load.
4. Ethernet address (Ethernet circuits only) - the unique address that
the target Ethernet device will respond to.
5. Service circuit - this identifies at the end of which wire to expect
the target.
6. Enable SERVICE for the circuit being downline loaded. This enables
the DECnet software to start the downline load process on the host.
7. Make sure event logging is enabled, or you'll miss error messages.
8. It may seem obvious, but make sure that the target comm device
you're using, and the processor bootstrap are *capable* of doing
what you ask. For details, see uNote #015, "Q-bus Hardware
Bootstraps"
4 RSX-11S OVERVIEW
Configure the RSX-11S image on a VAX/VMS, RSX-11M or RSX-11M+ system,
using the normal tools (SYSGEN, MAC, TKB, VMR). Prepare and build the
host loader table. (Refer to the References section for documentation
on RSX downline load procedures)
5 VAXELN OVERVIEW
The program/VAXELN image development sequence is:
1. Develop the source modules
2. LINK the source modules with the RTLSHARE.OLB and RTL.OLB libraries
3. EBUILD the LINKed image to produce a bootable VAXELN system. To be
able to downline load the VAXELN image, you must select Boot Method
DOWNLINE in the VAXELN System Characteristics portion of EBUILD.
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4. Downline load the target over Ethernet (this is not the only method
of loading a VAXELN target). The target can be loaded through
EDEBUG commands, or via NCP LOAD/TRIGGER commands.
5. Debug the application and repeat steps 1-4.
+------------+ +------------+ +------------+ +------------+
|PASCAL or C |.OBJ |$ EPAS or |.EXE | $ EBUILD |.SYS | $ EDEBUG |
|source prog.|---->|$ CC |---->| |---->| or NCP |
+------------+ +------------+ +------------+ +------------+
^
| Other VAXELN
| modules
|
VAXELN Program development sequence
6 OBSERVING & DEBUGGING
There are a variety of error indications, and diagnostic aids available.
Some are at the hardware level (comm device diagnostic LEDs), some from
the host software (upline dump for RSX-11S, EDEBUG for VAXELN). Others
are provided by the DECnet components that handle downline load, through
the EVL (EVent logger) capability. Some diagnostic facilities:
1. Device status LEDs give a numeric indication as to potential
hardware, or hardware configuration problems with the interface or
its connections.
2. Event logging messages:
- Event code 0.3 - Auto service: indication that a portion of a
DLL is taking place.
- Event code 0.7 - Aborted service request: indication that a
portion of a DLL load request is failing. This is not always
bad. For example, it is an acceptable "error" when multiple
hosts (on an Ethernet) offer service and the target accepts only
one. The remaining systems report event 0.7. EVL messages come
with varying amounts of diagnostic information. A 0.3 or 0.7
event includes the type of load being requested, from where it
is requested, to whom it is requested, etc.
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3. Failure message from NCP on LOAD/TRIGGER commands - may give some
insight as to the source of the problem
4. Line/circuit counters - indicate how much data has been transmitted
and received , and what errors have occurred.
Remember: Enable event logging: NCP SET LOGGING KNOWN
EVENTS STATE ON. Otherwise, EVL will not display this diagnostic
information!
7 EXAMPLES
One the next three pages are examples showing the successful load of a
terminal server and a VAXELN target. The appearance of the output will
be approximately the same for your targets, only with different node
names and files.
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$ reply/enable=network
%%%%%%%%%%% OPCOM 26-JUL-1985 13:09:11.96 %%%%%%%%%%%
Operator _FURILO$RTA1: has been enabled, username BLESSLEY
%%%%%%%%%%% OPCOM 26-JUL-1985 13:09:11.99 %%%%%%%%%%%
Operator status for operator _FURILO$RTA1:
NETWORK
$ run sys$system:ncp
NCP>show node hobson characteristics !Hobson is a DECserver 100
Node Volatile Characteristics as of 26-JUL-1985 13:10:49
Remote node = 13.102 (HOBSON)
Service circuit = UNA-0
Hardware address = 08-00-2B-02-0F-5F
Load file = SYS$SYSROOT:[DECSERVER]PS0801ENG.SYS
Dump file = SYS$SYSROOT:[DECSERVER]PSDMP0F5F.SYS
NCP>trigger node hobson
NCP>^Z
%%%%%%%%%%% OPCOM 26-JUL-1985 13:10:13.16 %%%%%%%%%%%
Message from user DECNET on FURILO
DECnet event 0.3, automatic line service
From node 7.272 (FURILO), 26-JUL-1985 13:10:13.04
Circuit UNA-0, Load, Requested, Node = 13.102 (HOBSON)
File = MOM$LOAD:PS0801ENG, Operating system, Ethernet address
= 08-00-2B-02-0F-5F
%%%%%%%%%%% OPCOM 26-JUL-1985 13:10:18.08 %%%%%%%%%%%
Message from user DECNET on FURILO
DECnet event 0.3, automatic line service
From node 7.272 (FURILO), 26-JUL-1985 13:10:16.40
Circuit UNA-0, Load, Successful, Node = 13.102 (HOBSON)
File = MOM$LOAD:PS0801ENG, Operating system,
Ethernet address = 08-00-2B-02-0F-5F
DECserver-100 Downline Load Example
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Below is an example of down-line load of a MicroVAX II system using
EDEBUG. The first part of the illustration shows the DECnet volatile
database entries for the target, as seen from the system that ultimately
boots the target, and from another that fails to boot the target.
[This command is issued on system "BELKER"]
BELKER> NCP SHOW NODE TUBBS CHARACTERISTICS
Node Volatile Characteristics as of 7-AUG-1985 10:38:59
Remote node = 7.453 (TUBBS)
Service circuit = UNA-0
Hardware address = 08-00-2B-02-1C-63
Load file = DISK$USER:[SAMPLE.ELN]CHER.SYS;
[This command is issued from system "FURILO"]
FURILO> NCP SHOW NODE TUBBS CHARACTERISTICS
Node Volatile Characteristics as of 7-AUG-1985 10:40:52
Remote node = 7.453 (TUBBS)
Load file = DISK$USER:[SAMPLE.ELN]CHER.SYS;
-----------------------------------------------------------------------
Command to downline load the VAXELN image from EDEBUG:
[This command and related output is from system "BELKER"]
$ EDEBUG/LOAD=PROG1 TUBBS
Edebug V2.0-00
Loading "TUBBS"
Connecting to "TUBBS"
.
.
.
(screen mode debugger)
Event log messages resulting from the EDEBUG command:
DECnet event 0.7, aborted service request
From node 7.272 (FURILO), 6-AUG-1985 16:13:14.46
Circuit UNA-0, Line open error, Unrecognized component, Node
Ethernet address = 08-00-2B-02-1C-63
^ FURILO:: didn't have this address defined in its
volatile database so it couldn't service the request
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DECnet event 0.3, automatic line service
From node 7.190 (BELKER), 6-AUG-1985 16:12:51.34
Circuit UNA-0, Load, Requested, Node = 7.453 (TUBBS)
File = DISK$USER:[SAMPLE.ELN]CHER.SYS;, Operating system
Ethernet address = 08-00-2B-02-1C-63
^ BELKER:: did have the address, corresponding to an
entry for "TUBBS::" Here, the target system is
requesting an operating system load. BELKER's DECnet
software is acknowledging the request.
DECnet event 0.3, automatic line service
From node 7.190 (BELKER), 6-AUG-1985 16:12:57.62
Circuit UNA-0, Load, Successful, Node = 7.453 (TUBBS)
File = DISK$USER:[SAMPLE.ELN]CHER.SYS;, Operating system
Ethernet address = 08-00-2B-02-1C-63
BELKER responds with packet(s) containing the
requested O.S. code for the target
8 SUMMARY
This Micronote has presented an overview of the downline loading
process. Many "components" are involved in the process - at least two
CPUs and at least two communication interfaces, target operating system
and images plus host, target, and executor DECnet software. The
procedure is akin to bringing up a complex, customized operating system
up on a remote processor, without a local load device. Once configured,
it offers the benefits of not requiring any mass storage devices
(resulting in higher MTBF and lower cost), plus the ability to bootstrap
a processor which my be physically inaccessible. There is a great
amount of information on DECnet downline load. There is no single
compendium, although each of the supported operating systems, plus
VAXELN have a chapter on the subject.
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9 REFERENCES
All of the following references are to Digital publications.
DECnet-RSX Volume IV - System Manager's Guide AA-H224C-TC
Guide to Networking VAX/VMS - AA-Y512A-TE (chapter 4)
QMA DMV11 Synchronous Controller Technical Manual EK-DMVQM-TM
DEQNA User's Guide EK-DEQNA-UG
DECnet Digital Network Architecture (Phase IV) General Description
AA-N149A- TC
DECnet Digital Network Architecture (Phase IV) Maintenance
Operations Functional Specification AA-X436A-TC
Networks and Communications Buyer's Guide ED-26347
"VAXELN Installation and Programming" AA-Z454A-TE
"MicroVax I Owner's Manual" EK-KD32-OM
"MicroVAX I Owner's Manual" (Release Notes) EK-KD32A-OM-CN1
Micronote #015, "Q-Bus Hardware Bootstraps"
Software Product Descriptions:
DECnet-11S #10.74
DECnet-11M #10.75
DECnet-11M+ #10.66
DECnet-VAX #25.03
377
