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OpenVMS Frequently Asked Questions (FAQ), Part 10/11

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Archive-name: dec-faq/vms/part10
Posting-Frequency: quarterly
Last-modified: 02 Sep 2005
Version: VMSFAQ_20050902-10.TXT


                   Hardware Information

                      of a new or replacement server. You may or may
                      not have some success looking for this or of any
                      other now-unavailable sites using the world-wide
                      web archives at:


          14.21  Why does my LK401 keyboard unexpectedly autorepeat?

                   There are several modes of failure:

                   o  Pressing 2 and 3 keys at the same time causes
                      one key to autorepeat when released. Check the
                      hardware revision level printed on the bottom of
                      the keyboard. If the revision level is C01, the
                      keyboard firmware is broken. Call field service to
                      replace the keyboard with any revision level other
                      than C01.

                   o  Pressing certain keys is always broken. Typical
                      symptoms are: delete always causes a autorepeat,
                      return needs to be pressed twice, etc. This is
                      frequently caused by having keys depressed while
                      the keyboard is being initialized. Pressing ^F2
                      several times or unplugging and replugging the
                      keyboard frequently fix this problem. (Ensure you
                      have current ECO kits applied; there is a patch
                      available to fix this problem.)

                   o  A key that was working spontaneously stops working
                      correctly. This may be either of the two previous
                      cases, or it may be bad console firmware. Ensure
                      that you have the most recent firmware installed
                      on your Alpha system. In particular, an old version
                      of the DEC 3000 SRM firmware is known to have a bug
                      that can cause this keyboard misbehaviour.


                   Hardware Information

          14.22  Problem - My LK411 sends the wrong keycodes or some keys
                 are dead

                   Check the firmware revision on the keyboard. Hardware
                   revision B01 introduced an incompatability with the
                   device driver which causes the keyboard to not be
                   recognized correctly. There is a patch available to
                   fix this problem: [AXPDRIV06_061] - the fix is also
                   included in OpenVMS V6.2. The rev A01 keyboard, and the
                   LK450 should work without problems.

                   If you are working from another operating system
                   platform, please see the DECxterm tool and related
                   information on OpenVMS Freeware V5.0.

          14.23  Which DE500 variant works with which OpenVMS version?

                   Ensure you have a version of the Alpha SRM console
                   with support for the DE500 series device. Apply ALL
                   mandatory ECO kits for the OpenVMS version in use, and
                   also apply the CLUSIO, ALPBOOT, and ALPLAN kits, and
                   apply any available ALPCPU ECO kit for the platform.

                   o  DE500-XA
                      auto-detection, no auto-negotiation,
                      OpenVMS V6.2-1H1 and ALPBOOT ECO, also V7.0 and
                      later and ECO.
                      Device hardware id 02000011 and 02000012.
                      Component part number 54-24187-01

                   o  DE500-AA
                      auto-detection, auto-negotiation,
                      OpenVMS V6.2 and ALPBOOT and ALPLAN ECOs, or V7.1
                      and later and ECO.
                      Device hardware id 02000020 and 20000022.
                      Component part number 54-24502-01

                   o  DE500-BA
                      auto-detection, auto-negotiation,
                      OpenVMS V6.2-1H3 and CLUSIO, ALPBOOT, ALPLAN and
                      ALPCPU ECOs, or V7.1-1H1 or later and ECO.
                      Device hardware id 02000030 (check connector, vs
                      DE500-FA) (other values on old Alpha SRM firmware)
                      Component part number 54-24602-01


                   Hardware Information

                   o  DE500-FA (100 megabit fibre optic Ethernet)
                      OpenVMS V7.1-1H1 and later
                      Device hardware id 02000030 (check connector, vs
                      DE500-BA) (other values possible on old Alpha SRM
                      Component part number 54-24899-01

                   To check the DE500 device hardware id from OpenVMS, use
                   the following command:

                   $ ANALYZE/SYSTEM
                   SDA> SHOW LAN/DEVICE=EWc:

                   The "hardware version" will be displayed.

                   To set the DE500 speed and duplex settings via the
                   associated Alpha SRM console environment variable, see
                   Table 14-4.

          Table 14-4  DE500 Speed and Duplex Settings


          Twisted-Pair                      10 Mbit/sec, nofull_duplex

          Full Duplex, Twisted-Pair         10 Mbit/sec, full_duplex

          AUI                               10 Mbit/sec, nofull_duplex

          BNC                               10 Mbit/sec, nofull_duplex

          Fast                              100 Mbit/sec, nofull_duplex

          FastFD (Full Duplex)              100 Mbit/sec, full_duplex


                   To override the console setting and use LANCP:

          LANCP> SET DEVICE EWA0/SPEED=100/full_duplex
          LANCP> DEFINE DEVICE EWA0/SPEED=100/full_duplex


                   Hardware Information

                   Fast Ethernet (100Base, 100 megabit) controllers
                   such as the DE500 series have a pair of connections
                   available-while traditional Ethernet (10Base, 10
                   megabit) is inherently a half-duplex protocol, Fast
                   Ethernet can be configured to use one or both of the
                   available connections, depending on the controller.
                   Fast Ethernet can thus be half- or full-duplex
                   depending on the configuration and the capabilities
                   of the network controller and the Ethernet network
                   plant. Some Fast Ethernet controllers can also operate
                   at traditional Ethernet speeds, these controllers are
                   thus often refered to as 10/100 Ethernet controllers.

          14.24  How do I set the speed and duplex on OpenVMS I64?

                   OpenVMS I64 on Integrity servers does not provide a
                   console-level environment variable akin to the SRM
                   console variables used to manage the network speed and
                   duplex settings on OpenVMS Alpha and Alpha systems.
                   On OpenVMS I64 on Integrity servers, LANCP is used to
                   manage the speed and the duplex setting of the network

          LANCP> SET DEVICE EWA0/SPEED=100/full_duplex
          LANCP> DEFINE DEVICE EWA0/SPEED=100/full_duplex

                   The EFI-level network bootstrap operations for a
                   network-based upgrade or a network-based installation
                   of OpenVMS I64 require the use of autonegotiation and a
                   switch capable of supporting it.

                   See Section 14.23 for a related discussion.

          14.25  Third-party or Unsupported

                   A wide variety of third-party and formally-unsupported
                   widgets-SCSI and ATA/ATAPI (IDE) disks and tapes,
                   graphics controllers, etc-are obviously widely
                   available, and are used on various platforms.


                   Hardware Information

                   If you purchase third-party or unsupported or generic
                   SCSI, ATA/ATAPI (IDE) storage devices, you and your
                   device vendor will be responsible for the testing and
                   the support of the devices. In general, you can expect
                   that HP will address non-standards-compliance problems
                   within OpenVMS (changes that will also not prevent
                   operations with other supported devices, of course),
                   but you and/or the device vendor and/or the device
                   manufacturer are responsible for finding and fixing
                   problems in the particular third-party device and or
                   controller involved.

                   In particular, realize that neither SCSI nor ATA/ATAPI
                   (IDE) is a particularly standard interface, these
                   interfaces tend to be a collection of optionally-
                   implemented and standardized interface features. You
                   should not and can not simply assume that all SCSI nor
                   ATA/ATAPI (IDE) storage devices are interchangeable.
                   If you want to try to use a generic SCSI device, use
                   V6.2 or later, or (better) V7.1-2 or later. If you wish
                   to try to use ATA/ATAPI (IDE), use OpenVMS V7.1-2 or

                   On older OpenVMS releases, see the disk capacity limits
                   (Section 9.5).

                   With SCSI disks on releases prior to V6.2, ensure
                   that you have the ARRE and ARWE settings configured
                   correctly (disabled). (If not, you will see DRVERR
                   fatal drive errors and error log entries.)

                   Some SCSI disks set the medium type byte as part of
                   the SCSI size field-this is a SET CAPACITY extension to
                   SCSI specs. This problem also applies to VAX V7.1 and

                   Disks with SCSI disk sizes past 8.58 GB and/or with
                   the SET CAPACITY extension require ALPSCSI07 ECO or the
                   OpenVMS Alpha V7.1-2 or later release. (See Section 9.5
                   for further details.)

                   Based on the displays of the (undocumented)
                   SYS$ETC:SCSI_INFO tool; this tool is present in OpenVMS
                   V6.2 and later:


                   Hardware Information

          Issuing 6-byte MODE SENSE QIOW to get current values for page 01h
                 Page Code ................. 01h
                 Page Name ................. Read-Write Error Recovery
                 Saveable .................. Yes
                 Size ...................... 10
                 Hex Data .................. E6 08 50 00 00 00 08 00
                                             00 00

                   The E6 shown indicates that the AWRE and ARRE bits are
                   set, and this is incompatible with OpenVMS versions
                   prior to V6.2. Further along in the same SCSI_INFO
                   display, if you also see:

          Issuing 6-byte MODE SENSE QIOW to get changeable values for page 81h
                 Page Code ................. 01h
                 Page Name ................. Read-Write Error Recovery
                 Saveable .................. Yes
                 Size ...................... 10
                 Hex Data .................. C0 08 50 00 00 00 08 00
                                             00 00

                   The C0 value means that the AWRE and ARRE values can
                   be changed on this particular SCSI device. (This is
                   not always the case.) If the bits are set, you can use
                   RZDISK from the OpenVMS Freeware, and can reset the E6
                   flag byte to hexadecimal 26 (or whatever the remaining
                   mask when you remove bits C0) on page one.

                   Each SCSI and ATA/ATAPI (IDE) host contains non-trivial
                   SCSI and IDE driver software, and each device contains
                   equally non-trivial firmware- taken together with the
                   mechanical and electronic components, this software
                   and firmware will determine whether or not a particular
                   device will function as expected.

                   Also note that various devices-such as various SCSI
                   CD-R devices -can implement and can require vendor-
                   specific protocol extensions, and these extensions
                   can require modifications to OpenVMS or the addition
                   of various utilities. In various of these cases,
                   these devices perform functions that will require
                   them to use SCSI or ATA/ATAPI (IDE) commands that
                   are (hopefully) architecturally-compatible SCSI
                   or ATA/ATAPI (IDE) command extensions. (Also see
                   Section 7.1 and Section 9.7.)


                   Hardware Information

                   Some SCSI tapes lack odd-byte transfer support, making
                   operations with OpenVMS problematic at best, as OpenVMS
                   expects odd-byte support. Examples of such include
                   LTO-1 devices such as the HP Ultrium 230 series tape,
                   and the DLT VS80 series tapes. Due to the lack of odd-
                   byte transfer support, LTO-1 devices are not supported
                   by OpenVMS. LTO devices in the LTO-2 and later series
                   do reportedly presently all have odd-byte transfer
                   support, and operations are reportedly rather easier.
                   Do check for formal support, of course.

                   In order for OpenVMS to officially support a particular
                   device, integration and testing work is mandated. There
                   can be no certainty that any particular device will
                   operate as expected in any particular configuration
                   without first performing this (non-trivial) work.

                   It is quite possible to find two devices-both entirely
                   compliant with applicable standards or interface
                   documents-that will not interoperate.

                   The same general statement holds for OpenVMS
                   bootstrapping on an unsupported VAX or Alpha platform.
                   It might or might not work. In particular, please see
                   the OpenVMS Software Product Description (SPD) for
                   the list of platforms supported by OpenVMS. OpenVMS
                   is not supported on the Personal Workstation -a
                   series, on the Digital Server series platforms, on
                   the AlphaServer 2100 series 5/375 CPU, on the Multia,
                   on the AlphaServer DS20L, and on a variety of other
                   platforms. (You might or might not see success booting
                   OpenVMS on any of these platforms.)

          14.25.1  Lists of third-party widgets on OpenVMS?

                   Various folks have successfully used common third-party
                   disk disk devices with OpenVMS, such as the ATA (IDE)
                   and SCSI variants of the Iomega Zip250 removable disk

                   Common SCSI CD-R/CD-RW devices such as the Plextor
                   PlexWriter 12/10/32S SCSI series and the HP DVD200i
                   series (recording CD-R) have also been successfully
                   utilized with various AlphaStation and VAXstation


                   Hardware Information

                   systems, and with tools such as CDRECORD. (A Plextor
                   PlexWriter burn of 614400000 bytes (300000 sectors)
                   requires just over six minutes at 12x, using an
                   AlphaStation XP1000 666 MHz EV67 system UltraSCSI
                   host.) (See Section 9.7 for detailed discussions of
                   recording optical media on OpenVMS, and the available

                   If you choose to attempt to use third-party devices,
                   ensure that you have the most current OpenVMS version
                   and the most current ECO kit(s) applied. In the
                   specific case of the ATA (IDE) Iomega Zip250 drive,
                   ensure that you have the most current revision of
                   SYS$DQDRIVER installed.

          14.25.2  Are the 2X-KZPCA-AA and SN-KZPCA-AA LVD Ultra2 SCSI?

                   Yes. Both of these controllers are Ultra2 low-voltage
          _________differential_(LVD)_SCSI controllers.

          14.25.3  Resolving DRVERR fatal device error?

                   If this is on an OpenVMS version prior to V6.2, please
                   see the AWRE and ARRE information included in section
                   Section 14.25.

          14.26  Looking for connector wiring pin-outs?

                   The DECconnect DEC-423 Modified Modular Jack (MMJ)
                   appears similar to a telphone or network modular jac,
                   though with the key offset to one side. The DECconnect
                   MMJ connector pin-out is listed in Table 14-5, with an
                   end-on view of the connector pins and the connector key
                   shown below.

          Table 14-5  DEC MMJ Pin-out


                   1       Data Terminal Ready (DTR)

                   2       Transmit (TXD)

                   3       Transmit Ground (TXD-)


                   Hardware Information

          Table 14-5 (Cont.)  DEC MMJ Pin-out


                   4       Receive Ground (RXD-)

                   5       Receive (RXD)


             | 1  2  3  4  5  6 |
             +------------+    ++

                   The BC16E-nn (where the "-nn" indicates the cable
                   length) cabling and keying "flips over" or "crosses-
                   over" the signal wires, and this allows all DECconnect
                   MMJ connections to be wired identically; the ends of
                   the BC16E are symmetrical and fully interchangeable,
                   and allows either end of the cable to be connected
                   either to the terminal or to the host. Specifically,
                   the BC16E-nn cross-over wiring looks like this:

                  Terminal                         Host
                  MMJ                              MMJ

               DTR 1 --->---------->----------->--- 6 DSR
               TXD 2 --->---------->----------->--- 5 RXD
                   3 ------------------------------ 4
                   4 ------------------------------ 3
               RXD 5 ---<----------<-----------<--- 2 TXD
               DSR 6 ---<----------<-----------<--- 1 DTR

                   DECconnect parts and connections are available from
                   HP, and MMJ crimping dies for use in typical telco-
                   style crimping tools, and MMJ connectors, are available
                   from Blackbox and from other communications equipment

                   The PC-compatible DB9 connector pin-out found on Alpha
                   and Integrity COM serial ports-and on most PC systems
                   is listed in Table 14-6.


                   Hardware Information

          Table 14-6  PC DB9 Pin-out


                   1       Data Carrier Detect (DCD)

                   2       Received Data

                   3       Transmit Data

                   4       Data Terminal Ready (DTR)

                   5       Ground

                   6       Data Set Ready (DSR)

                   7       Request To Send (RTS)

                   8       Clear To Send


                   The MicroVAX DB9 console connector pin-out predates
                   the PC-style DB9 pin-out (adapters discussed in
                   Section 14.27), and uses a then-common (and older)
                   standard pin-out, and uses the EIA-232 series standard
                   signals shown in Table 14-7.

          Table 14-7  MicroVAX DB9 Pin-out


                   1       Protective Ground

                   2       Transmited Data

                   3       Received Data

                   4       Request To Send (RTS)

                   5       Data Terminal Ready (DTR)

                   6       Data Set Ready (DSR)

                   7       Signal Ground

                   8       Shorted to pin 9 on MicroVAX and VAXstation


                   When pin 8 is shorted to pin 9, this is a BCC08 (or
                   variant) cable, most commonly used as a console cable


                   Hardware Information

                   on the MicroVAX 2000 and VAXstation 2000 series. (Other
                   systems may or may not tolerate connecting pin 8 to pin

                   The BN24H looks like this:

                        MMJ       RJ45


                   The BN24J looks like this:

                        MMJ       RJ45


                   Also see:




                   o  For adapters and connectors, see Section 14.27.

          14.27  What connectors and wiring adapters are available?

                   The H8571-B and H8575-B convert the (non-2000-series)
                   MicroVAX DB9 to the DECconnect DEC-423 Modified
                   Modular Jack (MMJ) pin-out; to the MMJ DECconnect
                   wiring system. The MicroVAX 2000 and VAXstation 2000
                   requires a BCC08 cable (which has the 8-9 short, see
                   Section 14.26) and the H8571-C or the H8571-D DB25-to-
                   MMJ adapter for use with DECconnect. (For a discussion
                   of the console bulkhead on the MicroVAX II series and
                   on other closely-related series systems, please see


                   Hardware Information

                   Somewhat less ancient HP (HP, Compaq or DIGITAL logo)
                   systems will use either the DECconnect MMJ wiring
                   directly or-on most (all?) recent system designs-
                   the PC-compatible DB9 9-pin pin-out; the PC-style COM
                   serial port interface and connection.

                   There are two DB9 9-pin pin-outs, that of the H8571-
                   B and similar for the MicroVAX and other and older
                   systems, and that of the H8571-J for the PC-style COM
                   port, AlphaStation, Integrity, and other newer systems.
                   The older MicroVAX DB9 and the PC-style DB9 pin-outs
                   are not compatible.

          Table 14-8  DECconnect MMJ Connectors and Adapters


                   H8571-A     EIA232 DB25 25-pin female (common).
                               Functionally similar to the H8575-A, though
                               the H8575-A has better ESD shielding.

                   H8571-B     Older MicroVAX (other than the MicroVAX
                               2000) DB9 EIA232 serial port. Functionally
                               similar to the H8575-B, though the H8575-B
                               has better ESD shielding. Note: Cannot be
                               used on a PC, Alpha nor Integrity DB9 9-pin

                   H8571-C     25 pin DSUB Female to MMJ, Unfiltered

                   H8571-D     EIA232 25 pin male (modem-wired)

                   H8571-E     25 pin DSUB Female to MMJ, Filtered

                   H8571-J     PC, Alpha, Integrity 9 pin (DB9) male (PC-
                               style COM serial port) Note: Cannot be used
                               on the older MicroVAX DB9 9-pin connector

                   H8572-0     BC16E MMJ double-female (MMJ extender)

                   H8575-A     EIA232 DB25 25-pin female (common).
                               Functionally similar to the H8571-A, though
                               the H8575-A has better ESD shielding.


                   Hardware Information

          Table 14-8 (Cont.)  DECconnect MMJ Connectors and Adapters


                   H8575-B     Older MicroVAX (other than the MicroVAX
                               2000) DB9 EIA232 serial port. Functionally
                               similar to the H8571-B, though the H8575-B
                               has better ESD shielding. Note: Cannot be
                               used on a PC, Alpha nor Integrity DB9 9-pin

                   H8575-D     25 Pin to MMJ with better ESD Protection

                   H8575-D     25 Pin to MMJ with better and ESD

                   H8575-E     25 Pin Integrity rx2600 Management
                               Processor (MP) port to MMJ, with ESD

                   H8577-AA    6 pin Female MMJ to 8 pin MJ

                   BC16E-**    MMJ cable with connectors, available in

                   Numerous additional adapters and cables are available
                   from the (now out of print) OPEN DECconnect Building
                   Wiring Components and Applications Catalog, as well as
                   descriptions of the above-listed parts.

                   The DECconnect wiring system has insufficient signaling
                   for modems, and particularly lacks support for modem
                   control signals.

                   The H8571-A and H8575-A are MMJ to DB25 (female) and
                   other connector wiring diagrams and adapter-, cable-
                   and pin-out-related discussions are available at:


                   Jameco has offered a USB-A to PS/2 Mini DIN 6 Adapter
                   (as part 168751), for those folks wishing to (try to)
                   use PS/2 Keyboards via USB-A connections.

                   The LK463 USB keyboard is also a potential option, for
                   those wishing to connect an OpenVMS keyboard to USB
                   systems or (via the provided adapter) to PS/2 systems.
                   The LK463 provides the classic OpenVMS keyboard and


                   Hardware Information

                   keyboard layout on USB-based system configurations,
                   including operations with the USB connection on
                   specific Alpha systems (and specifically on those with
                   supported USB connections) and on Integrity servers.

                   For information on the Alpha console COM port(s) or on
                   the VAX console port, please see Section 14.3.

          14.28  What is flow control and how does it work?

                   XON/XOFF is one kind of flow control.

                   In ASCII, XON is the <CTRL/Q> character, and XOFF is
                   the <CTRL/S>.

                   XON/XOFF flow control is typically associated with
                   asynchronous serial line communications. XON/XOFF is an
                   in-band flow control, meaning that the flow control is
                   mixed in with the data.

                   CTS/RTS is another type of flow control, and is
                   sometimes called hardware flow control. Out-of-band
                   means that seperate lines/pins from the data lines
                   (pins) are used to carry the CTS/RTS signals.

                   Both kinds of flow control are triggered when a
                   threshold is reached in the incoming buffer. The flow
                   control is suppose to reach the transmitter in time to
                   have it stop transmitting before the receiver buffer is
                   full and data is lost. Later, after a sufficient amount
                   of the receiver's buffer is freed up, the resume flow
                   control signal is sent to get the transmitter going

                   DECnet Phase IV on OpenVMS VAX supports the use of
                   asynchronous serial communications as a network
                   line; of asynch DECnet. The communication devices
                   (eg. modems, and drivers) must not be configured
                   for XON/XOFF flow control. The incidence of these
                   (unexpected) in-band characters will corrupt data
                   packets. Further, the serial line device drivers
                   might normally remove the XON and XOFF characters
                   from the stream for terminal applications, but DECnet
                   configures the driver to pass all characters through
                   and requires that all characters be permitted. (The
                   communication devices must pass through not only the


                   Hardware Information

                   XON and XOFF characters, they must pass all characters
                   including the 8-bit characters. If data compression is
                   happening, it must reproduce the source stream exactly.
                   No addition or elimination of null characters, and full
                   data transparency.

                   An Ethernet network is rather different than an
                   asynchronous serial line. Ethernet specifies the
                   control of data flow on a shared segment using CSMA/CD
                   (Carrier Sense Multiple Access, with Collision Detect)
                   An Ethernet station that is ready to transmit listens
                   for a clear channel (Carrier Sense). When the channel
                   is clear, the station begins to transmit by asserting
                   a carrier and encoding the packet appropriately. The
                   station concurrently listens to its own signal, to
                   permit the station to detect if another station began
                   to transmit at the same time-this is called collision
                   detection. (The collision corrupts the signal in a
                   way that can reliably be detected.) Upon detecting the
                   collision, both stations will stop transmitting, and
                   will back off and try again a little later. (You can
                   see a log of this activity in the DECnet NCP network

                   DECnet provides its own flow control, above and beyond
                   the flow control of the physical layer (if any). The
                   end nodes handshake at the beginning to establish
                   a transmit window size-and a transmitter will only
                   send that much data before stopping and waiting for
                   an acknowledgement. The acknowledgement is only sent
                   when the receiver has confirmed the packet is valid. (A
                   well-configured DECnet generally avoids triggering any
                   underlying (out-of-band) flow control mechanism.)

          14.29  CD and DVD device requirements?

                   Read access to DVD-ROM, DVD+R/RW, DVD-R/RW, CD-ROM, and
                   CD-R/RW devices on ATAPI (IDE) connections is generally
                   handled transparently by SYS$DQDRIVER, and SYS$DQDRIVER
                   will transparently de-block the media-native 2048
                   byte disk blocks with the 512-byte blocks expected
                   by OpenVMS and by native OpenVMS software.


                   Hardware Information

                   Read access to DVD-ROM, DVD+R/RW, DVD-R/RW, CD-ROM, and
                   CD-R/RW devices on SCSI is handled by DKDRIVER, though
                   SYS$DKDRIVER will not transparently de-block the native
                   2048-byte disk blocks into the 512-byte blocks expected
                   by OpenVMS. The drive or external software is expected
                   to provide this de-blocking, thus either a 512-byte
                   block capable drive (such as all RRD-series SCSI CD-ROM
                   drives) is required, or host software is required for
                   a 2048-byte block drive. Third-party SCSI drives with
                   UNIX references in their support documentation or with
                   explicit 512-byte selectors or swiches will generally
                   (but not always, of course) operate with OpenVMS.

                   At least some of the Plextor PlexWriter SCSI drives
                   can be successfully accessed (for read and write) from
                   OpenVMS, as can at least one Pioneer SCSI DVD drive
                   (for CD media). The Pioneer SCSI DVD drive switches
                   to 2048 byte blocks for DVD media, and a block-size
                   conversion tool (written by Glenn Everhart) or other
                   similar tool can be applied.

                   OpenVMS also has supported HP DVD drives for the ATAPI
                   (IDE) bus.

                   For some related information (and details on a
                   commercial DVDwrite package), please see:


                   No device driver currently presently permits direct
                   block-oriented recording on DVD-RAM nor DVD+RW media,
                   nor other recordable or rewritable media.

                   Recording (writing) of CD and DVD optical media
                   requires a recording or media mastering application
                   or tool, and both commercial and non-commercial options
                   are available. See Section 9.7 for related details on
                   CDRECORD (both non-DVD and DVD versions are available,
                   and at least one commercial version is available),
                   and also see DVDwrite (commercial) or DVDRECORD (open


                   Hardware Information

                   For information on the GKDRIVER (SYS$GKDRIVER)
                   generic SCSI device driver and of the the IO$_DIAGNOSE
                   $qio[w] interfaces (of SYS$DKDRIVER, SYS$DNDRIVER and
                   SYS$DQDRIVER) that are utilized by most CD and DVD
                   recording tools to send commands to SCSI, USB or ATAPI
                   devices (most USB and ATA devices-or more correctly,
                   most ATAPI devices-can use SCSI-like command packets),
                   please see the SYS$EXAMPLES:GKTEST.C example, and see
                   DECW$EXAMPLES:DECW$CDPLAYER.C example and please see
                   the various associated sections of the OpenVMS I/O
                   User's Reference Manual.

                   For information on creating bootable optical media on
                   OpenVMS, please see Section 9.7.3.



          15       Information on Networks and Clusters

                   The following sections contain information on OpenVMS
                   Networking with IP and DECnet, and on clustering and
                   volume shadowing, on Fibre Channel, and on related
                   products and configurations.

          15.1  How to connect OpenVMS to a Modem?

                   Please see the Ask The Wizard area topics starting with
                   (81), (1839), (2177), (3605), etc.


                   For additional information on the OpenVMS Ask The
                   Wizard (ATW) area and for a pointer to the available
                   ATW archive, please see Section 3.8.

          15.2  OpenVMS and IP Networking?

                   The following sections contain information on OpenVMS
                   and IP networking, as well as IP printing topics.

          15.2.1  How to connect OpenVMS to the Internet?

                   Some tutorial information and tips for connecting
                   OpenVMS systems to the Internet are available at:


          15.2.2  Connecting to an IP Printer?

                   To connect a printer via the IP telnet or lpr/lpd
                   protocols, you will need to install and configure an IP
                   stack on OpenVMS, and configure the appropriate print


                   Information on Networks and Clusters

                   With current OpenVMS IP implementations, the choice
                   of telnet or lpr/lpd really amounts to determining
                   which of these works better with the particular printer

                   To support network printing, the printer must include
                   an internal or external NIC or JetDirect; an adapter
                   connecting the network and the printer.

                   While it is normally possible to use a host-connected
                   printer-when the host supports an LPD or telnet daemon,
                   and OpenVMS and most other operating systems have the
                   ability to serve locally-attached printers to other
                   hosts on the network-it is generally far easier and
                   far more effective to use a printer that is directly
                   attached to the network. If your present printer does
                   not have a NIC or a JetDirect, acquire an internal (if
                   available) or external NIC or JetDirect. Or replace the
                   printer. And obviously, most any operating system that
                   can serve its local printers usually also provides
                   a client that can access remote network-connected

                   Please see the Ask The Wizard (ATW) area topics-
                   starting with topic (1020)-for additional information
                   on IP-based network printing.


                   For additional information on the OpenVMS Ask The
                   Wizard (ATW) area and for a pointer to the available
                   ATW archive, please see Section 3.8.

                   Please see Section 15.2.3 for information on Postscript

          15.2.3  How do I connect a PostScript printer via TCP/IP?

                   Using TCP/IP Services (UCX) as the TCP/IP stack, it is
                   possible to configure queues using the UCX$TELNETSYM
                   (TCP/IP Services prior to V5.0) or TCPIP$TELNETSYM
                   (with V5.0 and later) in order to print to Postscript
                   printers. This assumes however that the printer itself
                   can convert whatever is passed to it into something
                   intelligible. As an example, if the printer has an IP


                   Information on Networks and Clusters

                   address of 123.456.789.101 and jobs should be passed to
                   port 9100 then :

                   $ INITIALIZE/QUEUE/ON="123.456.789.101:9100" -
                       /PROCESSOR=UCX$TELNETSYM  -

                   $ INITIALIZE/QUEUE/ON="123.456.789.101:9100" -
                       /PROCESSOR=TCPIP$TELNETSYM  -

                   The port number of 9100 is typical of HP JetDirect
                   cards but may be different for other manufacturers

                   As a better alternative, DCPS Version 1.4 and later
                   support IP queues using either HP TCP/IP Services
                   for OpenVMS software or Process Software Multinet
                   for OpenVMS. The usage of this type of interface is
                   documented in the DCPS documentation or release notes,
                   and the DCPS$STARTUP.TEMPLATE startup template file.

                   For general and additional (non-Postscript) IP printing
                   information, please see topic (1020) and other topics
                   referenced in that topic elsewhere within the Ask The
                   Wizard area.


                   For additional information on the OpenVMS Ask The
                   Wizard (ATW) area and for a pointer to the available
                   ATW archive, please see Section 3.8. Also


                   Please see Section 15.2.2 for pointers to an
                   introduction to IP printing.

          15.2.4  How do I set a default IP route or gateway on OpenVMS?

                   If you have TCP/IP Services, then use the command for
                   TCP/IP Services V5.0 and later:

                   $ TCPIP
                   SET ROUTE/GATE=x.x.x.x/DEFAULT/PERMANENT


                   Information on Networks and Clusters

                   And for earlier TCP/IP Services versions, use the

                   $ UCX
                   SET ROUTE/GATE=x.x.x.x/DEFAULT/PERMANENT

          15.2.5  How can I set up reverse telnet (like reverse LAT)?

                   Though it may seem obvious, Telnet and LAT are quite
                   different-with differing capabilities and design goals.

                   Please see the documentation around the TCP/IP Services
                   for OpenVMS TELNET command CREATE_SESSION. This command
                   is the equivilent of the operations performed in
                   LTLOAD.COM or LAT$SYSTARTUP.COM. There is no TELNET
                   equivilent to the sys$qio[w] control interface for
                   LTDRIVER (as documented in the I/O User's Reference
                   Manual) available, though standard sys$qio[w] calls
                   referencing the created TN device would likely operate
                   as expected.

          15.2.6  Why can't I use PPP and RAS to connect to OpenVMS Alpha?

                   OpenVMS Alpha IP PPP does not presently support
                   authentication, and the Microsoft Windows NT option
                   to disable authentication during a RAS connection
                   apparently doesn't currently work-RAS connections will
                   require authentication-and this will thus prevent RAS

                   Future versions of OpenVMS and TCP/IP Services may
                   add this, and future versions of Microsoft Windows may
                   permit operations with authentication disabled.

          15.3  OpenVMS and DECnet Networking?

                   The following sections contain information on OpenVMS
                   and DECnet networking.


                   Information on Networks and Clusters

          15.3.1  Can DECnet-Plus operate over IP?

                   Yes. To configure DECnet-Plus to operate over IP
                   transport and over IP backbone networks, install and
                   configure DECnet-Plus, and install and configure the
                   PWIP mechanism available within the currently-installed
                   IP stack. Within TCP/IP Services, this is a PWIPDRIVER
                   configuration option within the UCX$CONFIG (versions
                   prior to V5.0) or TCPIP$CONFIG (with V5.0 and later)
                   configuration tool.

          15.3.2  What does "failure on back translate address request"

                   The error message:

                   BCKTRNSFAIL, failure on the back translate address request

                   indicates that the destination node is running DECnet-
                   Plus, and that its naming service (DECnet-Plus DECdns,
                   LOCAL node database, etc) cannot locate a name to
                   associate with the source node's address. In other
                   words, the destination node cannot determine the node
                   name for the node that is the source of the incoming

                   Use the DECNET_REGISTER mechanism (on the destination
                   node) to register or modify the name(s) and the
                   address(es) of the source node. Check the namespace
                   on the source node, as well.

                   Typically, the nodes involved are using a LOCAL
                   namespace, and the node name and address settings are
                   not coherent across all nodes. Also check to make sure
                   that the node is entered into its own LOCAL namespace.
                   This can be a problem elsewhere, however. Very rarely,
                   a cache corruption has been known to cause this error.
                   To flush the cache, use the command:

                   $ RUN SYS$SYSTEM:NCL
                   flush session control naming cache entry "*"


                   Information on Networks and Clusters

                   Also check to see that you are using the latest ECO for
                   DECnet-Plus for the version you are running. DECnet-
                   Plus can use the following namespaces:

                   o  DECdns: DECnet-Plus distributed name services.

                   o  LocalFile: a local file containing names and

                   o  DNS/BIND: the TCP/IP distributed name services

                   o  The TCP/IP Services (UCX) local host file.

                   Of these, searching DNS/BIND and LocalFile,
                   respectively, is often the most appropriate

          15.3.3  Performing SET HOST/MOP in DECnet-Plus?

                   First, issue the NCL command SHOW MOP CIRCUIT *

                   $ RUN SYS$SYSTEM:NCL
                   SHOW MOP CIRCUIT *

                   Assume that you have a circuit known as FDDI-0
                   displayed. Here is an example of the SET HOST/MOP
                   command syntax utilized for this circuit:

                   $ SET HOST/MOP/ADDRESS=08-00-2B-2C-5A-23/CIRCUIT=FDDI-0

                   Also see Section 15.6.3.

          15.3.4  How to flush the DECnet-Plus session cache?

                   $ RUN SYS$SYSTEM:NCL

          15.4  How to determine the network hardware address?

                   Most Alpha and most VAX systems have a console command
                   that displays the network hardware address. Many
                   systems will also have a sticker identifying the
                   address, either on the enclosure or on the network
                   controller itself.


                   Information on Networks and Clusters

                   The system console power-up messages on a number of VAX
                   and Alpha systems will display the hardware address,
                   particularly on those systems with an integrated
                   Ethernet network adapter present.

                   If you cannot locate a sticker on the system, if
                   the system powerup message is unavailable or does
                   not display the address, and if the system is at the
                   console prompt, start with the console command:


                   A console command similar to one of the following is
                   typically used to display the hardware address:

                   SHOW DEVICE
                   SHOW ETHERNET
                   SHOW CONFIG

                   On the oldest VAX Q-bus systems, the following console
                   command can be used to read the address directly off
                   the (DELQA, DESQA, or the not-supported-in-V5.5-and-
                   later DEQNA) Ethernet controller:

                   E/P/W/N:5 20001920

                   Look at the low byte of the six words displayed by
                   the above command. (The oldest VAX Q-bus systems-such
                   as the KA630 processor module used on the MicroVAX II
                   and VAXstation II series-lack a console HELP command,
                   and these systems typically have the primary network
                   controller installed such that the hardware address
                   value is located at the system physical address

                   If the system is a VAX system, and another VAX system
                   on the network is configured to answer Maintenance
                   and Operations Protocol (MOP) bootstrap requests
                   (via DECnet Phase IV, DECnet-Plus, or LANCP), the
                   MOM$SYSTEM:READ_ADDR.EXE tool can be requested:

                   B/R5:100 ddcu
                   Bootfile: READ_ADDR


                   Information on Networks and Clusters

                   Where ddcu is the name of the Ethernet controller in
                   the above command. The primarly local DELQA, DESQA,
                   and DEQNA Q-bus controllers are usually named XQA0.
                   An attempt to MOP download the READ_ADDR program will
                   ensue, and (if the download is successful) READ_ADDR
                   will display the hardware address.

                   If the system is running, you can use DECnet or
                   TCP/IP to display the hardware address with one of
                   the following commands.

                   $! DECnet Phase IV
                   $ RUN SYS$SYSTEM:NCP

                   $! DECnet-Plus
                   $ RUN SYS$SYSTEM:NCL
                   SHOW CSMA-CD STATION * ALL STATUS

                   $! TCP/IP versions prior to V5.0
                   $ UCX
                   SHOW INTERFACE/FULL

                   $! TCP/IP versions V5.0 and later
                   $ TCPIP
                   SHOW INTERFACE/FULL

                   A program can be created to display the hardware
                   address, reading the necessary information from
                   the network device drivers. A complete example C
                   program for reading the Ethernet or IEEE 802.3 network
                   controller hardware address (via sys$qio calls to the
                   OpenVMS network device driver(s)) is available at the
                   following URL:


                   To use the DECnet Phase IV configurator tool to watch
                   for MOP SYSID activity on the local area network:

                   $ RUN SYS$SYSTEM:NCP


                   Information on Networks and Clusters

                   Let the DECnet Phase IV configurator run for at least
                   20 minutes, and preferably longer. Then issue the
                   following commands:

                   $ RUN SYS$SYSTEM:NCP

                   The resulting file (named filename.txt) can now be
                   searched for the information of interest. Most DECnet
                   systems will generate MOP SYSID messages identifying
                   items such as the controller hardware address and the
                   controller type, and these messages are generated and
                   multicast roughly every ten minutes.

                   Information on the DECnet MOP SYSID messages and other
                   parts of the maintenance protocols is included in the
                   DECnet network architecture specifications referenced
                   in section DOC9.

          15.4.1  How do I reset the LAN (DECnet-Plus NCL) error counters?

                   On recent OpenVMS releases:

                   $ RUN SYS$SYSTEM:LANCP

          15.4.2  How do I install DECnet Phase IV on VMS 7.1?

                   On OpenVMS V7.1, all DECnet binaries were relocated
                   into separate installation kits-you can selectively
                   install the appropriate network: DECnet-Plus (formerly
                   known as DECnet OSI), DECnet Phase IV, and HP TCP/IP
                   Services (often known as UCX).

                   On OpenVMS versions prior to V7.1, DECnet Phase IV was
                   integrated, and there was no installation question. You
                   had to install the DECnet-Plus (DECnet/OSI) package on
                   the system, after the OpenVMS upgrade or installation


                   Information on Networks and Clusters

                   During an OpenVMS V7.1 installation or upgrade, the
                   installation procedure will query you to learn if
                   DECnet-Plus should be installed. If you are upgrading
                   to V7.1 from an earlier release or are installing V7.1
                   from a distribution kit, simply answer "NO" to the
                   question asking you if you want DECnet-Plus. Then-after
                   the OpenVMS upgrade or installation completes - use
                   the PCSI PRODUCT INSTALL command to install the DECnet
                   Phase IV binaries from the kit provided on the OpenVMS
                   software distribution kit.

                   If you already have DECnet-Plus installed and wish
                   to revert, you must reconfigure OpenVMS. You cannot
                   reconfigure the "live" system, hence you must reboot
                   the system using the V7.1 distribution CD-ROM. Then
                   select the DCL ($$$ prompt) option. Then issue the

                   $$$ DEFINE/SYSTEM PCSI$SYSDEVICE DKA0:
                   $$$ DEFINE/SYSTEM PCSI$SPECIFIC DKA0:[SYS0.]

                   The above commands assume that the target system device
                   and system root are "DKA0:[SYS0.]". Replace this with
                   the actual target device and root, as appropriate.
                   The RECONFIGURE command will then issue a series of
                   prompts. You will want to reconfigure DECnet-Plus off
                   the system, obviously. You will then want to use the
                   PCSI command PRODUCT INSTALL to install the DECnet
                   Phase IV kit from the OpenVMS distribution media.

                   Information on DECnet support, and on the kit names, is
                   included in the OpenVMS V7.1 installation and upgrade

                   Subsequent OpenVMS upgrade and installation procedures
                   can and do offer both DECnet Phase IV and DECnet-Plus


                   Information on Networks and Clusters

          15.5  How can I send (radio) pages from my OpenVMS system?

                   There are third-party products available to
                   send messages to radio paging devices (pagers),
                   communicating via various protocols such as TAP
                   (Telocator Alphanumeric Protocol); paging packages.

                   RamPage (Ergonomic Solutions) is one of the available
                   packages that can generate and transmit messages to
                   radio pagers. Target Alert (Target Systems; formerly
                   the DECalert product) is another. Networking Dynamics
                   Corp has a product called Pager Plus. The System
                   Watchdog package can also send pages. The Process
                   Software package PMDF can route specific email
                   addresses to a paging service, as well.

                   Many commercial paging services provide email contact
                   addresses for their paging customers-you can simply
                   send or forward email directly to the email address
                   assigned to the pager.

                   Some people implement the sending of pages to radio
                   pagers by sending commands to a modem to take the
                   "phone" off the "hook", and then the paging sequence,
                   followed by a delay, and then the same number that a
                   human would dial to send a numeric page. (This is not
                   entirely reliable, as the modem lacks "call progress
                   detection", and the program could simply send the
                   dial sequence when not really connected to the paging
                   company's telephone-based dial-up receiver.)

                   See Section 13.1 for information on the available
                   catalog of products.

          15.6  OpenVMS, Clusters, Volume Shadowing?

                   The following sections contain information on OpenVMS
                   and Clusters, Volume Shadowing, and Cluster-related
                   system parameters.


                   Information on Networks and Clusters

          15.6.1  OpenVMS Cluster Communications Protocol Details?

                   The following sections contain information on the
                   OpenVMS System Communications Services (SCS) Protocol.
                   Cluster terminology is available in Section

  OpenVMS Cluster (SCS) over DECnet? Over IP?

                   The OpenVMS Cluster environment operates over various
                   network protocols, but the core of clustering uses
                   the System Communications Services (SCS) protocols,
                   and SCS-specific network datagrams. Direct (full)
                   connectivity is assumed.

                   An OpenVMS Cluster does not operate over DECnet, nor
                   over IP.

                   No SCS protocol routers are available.

                   Many folks have suggested operating SCS over DECnet
                   or IP over the years, but SCS is too far down in
                   the layers, and any such project would entail a
                   major or complete rewrite of SCS and of the DECnet
                   or IP drivers. Further, the current DECnet and IP
                   implementations have large tracts of code that operate
                   at the application level, while SCS must operate in
                   the rather more primitive contexts of the system and
                   particularly the bootstrap-to get SCS to operate over a
                   DECnet or IP connection would require relocating major
                   portions of the DECnet or IP stack into the kernel.
                   (And it is not clear that the result would even meet
                   the bandwidth and latency expectations.)

                   The usual approach for multi-site OpenVMS Cluster
                   configurations involves FDDI, Memory Channel (MC2), or
                   a point-to-point remote bridge, brouter, or switch. The
                   connection must be transparent, and it must operate at
                   10 megabits per second or better (Ethernet speed), with
                   latency characteristics similar to that of Ethernet or
                   better. Various sites use FDDI, MC2, ATM, or point-to-
                   point T3 link.


                   Information on Networks and Clusters

  Configuring Cluster SCS for path load balancing?

                   This section discusses OpenVMS Cluster communications,
                   cluster terminology, related utilities, and command and
                   control interfaces.

  Cluster Terminology?

                   SCS: Systems Communication Services. The protocol used
                   to communicate between VMSCluster systems and between
                   OpenVMS systems and SCS-based storage controllers.
                   (SCSI-based storage controllers do not use SCS.)

                   PORT: A communications device, such as DSSI, CI,
                   Ethernet or FDDI. Each CI or DSSI bus is a different
                   local port, named PAA0, PAB0, PAC0 etc. All Ethernet
                   and FDDI busses make up a single PEA0 port.

                   VIRTUAL CIRCUIT: A reliable communications path
                   established between a pair of ports. Each port in a
                   VMScluster establishes a virtual circuit with every
                   other port in that cluster.

                   All systems and storage controllers establish "Virtual
                   Circuits" to enable communications between all
                   available pairs of ports.

                   SYSAP: A "system application" that communicates using
                   SCS. Each SYSAP communicates with a particular remote
                   SYSAP. Example SYSAPs include:

                   VMS$DISK_CL_DRIVER connects to MSCP$DISK
                   The disk class driver is on every VMSCluster system.
                   MSCP$DISK is on all disk controllers and all VMSCluster
                   systems that have SYSGEN parameter MSCP_LOAD set to 1

                   VMS$TAPE_CL_DRIVER connects to MSCP$TAPE
                   The tape class driver is on every VMSCluster system.
                   MSCP$TAPE is on all tape controllers and all VMSCluster
                   systems that have SYSGEN parameter TMSCP_LOAD set to 1

                   VMS$VAXCLUSTER connects to VMS$VAXCLUSTER
                   This SYSAP contains the connection manager, which
                   manages cluster connectivity, runs the cluster state
                   transition algorithm, and implements the cluster quorum


                   Information on Networks and Clusters

                   algorithm. This SYSAP also handles lock traffic, and
                   various other cluster communications functions.

                   SCS$DIR_LOOKUP connects to SCS$DIRECTORY
                   This SYSAP is used to find SYSAPs on remote systems

                   MSCP and TMSCP
                   The Mass Storage Control Protocol and the Tape MSCP
                   servers are SYSAPs that provide access to disk and
                   tape storage, typically operating over SCS protocols.
                   MSCP and TMSCP SYSAPs exist within OpenVMS (for OpenVMS
                   hosts serving disks and tapes), within CI- and DSSI-
                   based storage controllers, and within host-based MSCP-
                   or TMSCP storage controllers. MSCP and TMSCP can be
                   used to serve MSCP and TMSCP storage devices, and can
                   also be used to serve SCSI and other non-MSCP/non-TMSCP
                   storage devices.

                   SCS CONNECTION: A SYSAP on one node establishes an SCS
                   connection to its counterpart on another node. This
                   connection will be on ONE AND ONLY ONE of the available
                   virtual circuits.

  Cluster Communications Control?

                   When there are multiple virtual circuits between two
                   OpenVMS systems it is possible for the VMS$VAXCLUSTER
                   to VMS$VAXCLUSTER connection to use any one of these
                   circuits. All lock traffic between the two systems will
                   then travel on the selected virtual circuit.

                   Each port has a "LOAD CLASS" associated with it. This
                   load class helps to determine which virtual circuit
                   a connection will use. If one port has a higher load
                   class than all others then this port will be used. If
                   two or more ports have equally high load classes then
                   the connection will use the first of these that it
                   finds. Prior to enhancements found in V7.3-1 and later,
                   the load class is static and normally all CI and DSSI
                   ports have a load class of 14(hex), while the Ethernet
                   and FDDI ports will have a load class of A(hex). With
                   V7.3-1 and later, the load class values are dynamic.


                   Information on Networks and Clusters

                   For instance, if you have multiple DSSI busses and
                   an FDDI, the VMS$VAXCLUSTER connection will chose the
                   DSSI bus as this path has the system disk, and thus
                   will always be the first DSSI bus discovered when the
                   OpenVMS system boots.

                   To force all lock traffic off the DSSI and on to
                   the FDDI, for instance, an adjustment to the load
                   class value is required, or the DSSI SCS port must
                   be disabled.

                   In addition to the load class mechanisms, you can
                   also use the "preferred path" mechanisms of MSCP
                   and TMSCP services. This allows you to control the
                   SCS connections used for serving remote disk and tape
                   storage. The preferred path mechanism is most commonly
                   used to explicitly spread cluster I/O activity over
                   hosts and/or storage controllers serving disk or tape
                   storage in parallel. This can be particularly useful if
                   your hosts or storage controllers individually lack the
                   necessary I/O bandwidth for the current I/O load, and
                   must thus aggregate bandwidth to serve the cluster I/O

                   For related tools, see various utilities including
                   LAVC$STOP_BUS and LAVC$START_BUS, and see DCL commands
                   including SET PREFERRED_PATH.

  Cluster Communications Control Tools and Utilities?

                   In most OpenVMS versions, you can use the tools:

                   o  SYS$EXAMPLES:LAVC$STOP_BUS

                   o  SYS$EXAMPLES:LAVC$START_BUS

                   These tools permit you to disable or enable all SCS
                   traffic on the on the specified paths.

                   You can also use a preferred path mechanism that tells
                   the local MSCP disk class driver (DUDRIVER) which path
                   to a disk should be used. Generally, this is used with
                   dual-pathed disks, forcing I/O traffic through one of
                   the controllers instead of the other. This can be used


                   Information on Networks and Clusters

                   to implement a crude form of I/O load balancing at the
                   disk I/O level.

                   Prior to V7.2, the preferred path feature uses the

                   o  SYS$EXAMPLES:PREFER.MAR

                   In OpenVMS V7.2 and later, you can use the following
                   DCL command:

                   $ SET PREFERRED_PATH

                   The preferred path mechanism does not disable nor
                   affect SCS operations on the non-preferred path.

                   With OpenVMS V7.3 and later, please see the SCACP
                   utility for control over cluster communications, SCS
                   virtual circuit control, port selection, and related.

          15.6.2  Cluster System Parameter Settings?

                   The following sections contain details of configuring
                   cluster-related system parameters.

  What is the correct value for EXPECTED_VOTES in a

                   The VMScluster connection manager uses the concept
                   of votes and quorum to prevent disk and memory data
                   corruptions-when sufficient votes are present for
                   quorum, then access to resources is permitted. When
                   sufficient votes are not present, user activity will be
                   blocked. The act of blocking user activity is called
                   a "quorum hang", and is better thought of as a "user
                   data integrity interlock". This mechanism is designed
                   to prevent a partitioned VMScluster, and the resultant
                   massive disk data corruptions. The quorum mechanism is
                   expressly intended to prevent your data from becoming
                   severely corrupted.


                   Information on Networks and Clusters

                   On each OpenVMS node in a VMScluster, one sets two
                   values in SYSGEN: VOTES, and EXPECTED_VOTES. The
                   former is how many votes the node contributes to the
                   VMScluster. The latter is the total number of votes
                   expected when the full VMScluster is bootstrapped.

                   Some sites erroneously attempt to set EXPECTED_VOTES
                   too low, believing that this will allow when only a
                   subset of voting nodes are present in a VMScluster. It
                   does not. Further, an erroneous setting in EXPECTED_
                   VOTES is automatically corrected once VMScluster
                   connections to other nodes are established; user data
                   is at risk of severe corruptions during the earliest
                   and most vulnerable portion of the system bootstrap,
                   before the connections have been established.

                   One can operate a VMScluster with one, two, or many
                   voting nodes. With any but the two-node configuration,
                   keeping a subset of the nodes active when some nodes
                   fail can be easily configured. With the two-node
                   configuration, one must use a primary-secondary
                   configuration (where the primary has all the votes), a
                   peer configuration (where when either node is down, the
                   other hangs), or (preferable) a shared quorum disk.

                   Use of a quorum disk does slow down VMScluster
                   transitions somewhat - the addition of a third
                   voting node that contributes the vote(s) that would
                   be assigned to the quorum disk makes for faster
                   transitions-but the use of a quorum disk does mean
                   that either node in a two-node VMScluster configuration
                   can operate when the other node is down.


                      The quorum disk must be on a non-host-based
                      shadowed disk, though it can be protected
                      with controller-based RAID. Because host-based
                      volume shadowing depends on the lock manager
                      and the lock manager depends on the connection
                      manager and the connection manager depends on
                      quorum, it is not technically feasible (nor
                      even particularly reliable) to permit host-based
                      volume shadowing to protect the quorum disk.


                   Information on Networks and Clusters

                   If you choose to use a quoum disk, a QUORUM.DAT file
                   will be automatically created when OpenVMS first
                   boots and when a quorum disk is specified - well, the
                   QUORUM.DAT file will be created when OpenVMS is booted
                   without also needing the votes from the quorum disk.

                   In a two-node VMScluster with a shared storage
                   interconnect, typically each node has one vote, and
                   the quorum disk also has one vote. EXPECTED_VOTES is
                   set to three.

                   Using a quorum disk on a non-shared interconnect is
                   unnecessary-the use of a quorum disk does not provide
                   any value, and the votes assigned to the quorum disk
                   should be assigned to the OpenVMS host serving access
                   to the disk.

                   For information on quorum hangs, see the OpenVMS
                   documentation. For information on changing the
                   EXPECTED_VOTES value on a running system, see the
                   SET CLUSTER/EXPECTED_VOTES command, and see the
                   documentation for the AMDS and Availability Manager
                   tools. Also of potential interest is the OpenVMS
                   system console documentation for the processor-specific
                   console commands used to trigger the IPC (Interrrupt
                   Priority Level %x0C; IPL C) handler. (IPC is not
                   available on OpenVMS I64 V8.2.) AMDS, Availability
                   Manager, and the IPC handler can each be used to
                   clear a quorum hang. Use of AMDS and Availability
                   Manager is generally recommended over IPC, particularly
                   because IPC can cause CLUEXIT bugchecks if the system
                   should remain halted beyond the cluster sanity timer
                   limits, and because some Alpha consoles and most (all?)
                   Integrity consoles do not permit a restart after a

                   The quorum scheme is a set of "blade guards"
                   deliberately implemented by OpenVMS Engineering to
                   provide data integrity-remove these blade guards at
                   your peril. OpenVMS Engineering did not implement
                   the quorum mechanism to make a system manager's life
                   more difficult- the quorum mechanism was specifically
                   implemented to keep your data from getting scrambled.


                   Information on Networks and Clusters

  Why no shadowing for a Quorum Disk?

                   Stated simply, Host-Based Volume Shadowing uses the
                   Distributed Lock Manager (DLM) to coordinate changes to
                   membership of a shadowset (e.g. removing a member).
                   The DLM depends in turn on the Connection Manager
                   enforcing the Quorum Scheme and deciding which node(s)
                   (and quorum disk) are participating in the cluster, and
                   telling the DLM when it needs to do things like a lock
                   database rebuild operation. So you can't introduce a
                   dependency of the Connection Manager on Shadowing to
                   try to pick proper shadowset member(s) to use as the
                   Quorum Disk when Shadowing itself is using the DLM and
                   thus indirectly depending on the Connection Manager to
                   keep the cluster membership straight-it's a circular

                   So in practice, folks simply depend on controller-
                   based mirroring (or controller-based RAID) to protect
                   the Quorum Disk against disk failures (and dual-
                   redundant controllers to protect against most cases
                   of controller and interconnect failures). Since this
                   disk unit appears to be a single disk up at the VMS
                   level, there's no chance of ambiguity.

  Explain disk (or tape) allocation class settings?

                   The allocation class mechanism provides the system
                   manager with a way to configure and resolve served and
                   direct paths to storage devices within a cluster. Any
                   served device that provides multiple paths should be
                   configured using a non-zero allocation class, either
                   at the MSCP (or TMSCP) storage controllers, at the
                   port (for port allocation classes), or at the OpenVMS
                   MSCP (or TMSCP) server. All controllers or servers
                   providing a path to the same device should have the
                   same allocation class (at the port, controller, or
                   server level).

                   Each disk (or tape) unit number used within a non-
                   zero disk (or tape) allocation class must be unique,
                   regardless of the particular device prefix. For the
                   purposes of multi-path device path determination, any
                   disk (or tape) device with the same unit number and the


                   Information on Networks and Clusters

                   same disk (or tape) allocation class configuration is
                   assumed to be the same device.

                   If you are reconfiguring disk device allocation
                   classes, you will want to avoid the use of allocation
                   class one ($1$) until/unless you have Fibre Channel
                   storage configured. (Fibre Channel storage specifically
                   requires the use of allocation class $1$. eg:

  How to configure allocation classes and Multi-Path

                   The HSZ allocation class is applied to devices,
                   starting with OpenVMS V7.2. It is considered a port
                   allocation class (PAC), and all device names with a PAC
                   have their controller letter forced to "A". (You might
                   infer from the the text in the "Guidelines for OpenVMS
                   Cluster Configurations" that this is something you have
                   to do, though OpenVMS will thoughtfully handle this
                   renaming for you.)

                   You can force the device names back to DKB by setting
                   the HSZ allocation class to zero, and setting the PKB
                   PAC to -1. This will use the host allocation class, and
                   will leave the controller letter alone (that is, the
                   DK controller letter will be the same as the SCSI port
                   (PK) controller). Note that this won't work if the HSZ
                   is configured in multibus failover mode. In this case,
                   OpenVMS requires that you use an allocation class for
                   the HSZ.

                   When your configuration gets even moderately complex,
                   you must pay careful attention to how you assign
                   the three kinds of allocation class: node, port and
                   HSZ/HSJ, as otherwise you could wind up with device
                   naming conflicts that can be painful to resolve.

                   The display-able path information is for SCSI
                   multi-path, and permits the multi-path software to
                   distinguish between different paths to the same device.
                   If you have two paths to $1$DKA100, for example by
                   having two KZPBA controllers and two SCSI buses to the
                   HSZ, you would have two UCBs in a multi-path set. The


                   Information on Networks and Clusters

                   path information is used by the multi-path software to
                   distinguish between these two UCBs.

                   The displayable path information describes the path;
                   in this case, the SCSI port. If port is PKB, that's
                   the path name you get. The device name is no longer
                   completely tied to the port name; the device name now
                   depends on the various allocation class settings of the
                   controller, SCSI port or node.

                   The reason the device name's controller letter is
                   forced to "A" when you use PACs is because a shared
                   SCSI bus may be configured via different ports on the
                   various nodes connected to the bus. The port may be PKB
                   on one node, and PKC on the other. Rather obviously,
                   you will want to have the shared devices use the same
                   device names on all nodes. To establish this, you
                   will assign the same PAC on each node, and OpenVMS
                   will force the controller letter to be the same on
                   each node. Simply choosing "A" was easier and more
                   deterministic than negotiating the controller letter
                   between the nodes, and also parallels the solution used
                   for this situation when DSSI or SDI/STI storage was

                   To enable port allocation classes, see the SYSBOOT
                   command SET/BOOT, and see the DEVICE_NAMING system

                   This information is also described in the Cluster
                   Systems and Guidelines for OpenVMS Cluster
                   Configurations manuals.

          15.6.3  Tell me about SET HOST/DUP and SET HOST/HSC

                   The OpenVMS DCL commands SET HOST/DUP and SET HOST/HSC
                   are used to connect to storage controllers via the
                   Diagnostics and Utility Protocol (DUP). These commands
                   require that the FYDRIVER device driver be connected.
                   This device driver connection is typically performed by
                   adding the following command(s) into the system startup
                   command procedure:


                   Information on Networks and Clusters

                   On OpenVMS Alpha:


                   On OpenVMS VAX:


                   Alternatives to the DCL SET HOST/DUP command include
                   the console SET HOST command available on various mid-
                   to recent-vintage VAX consoles:

                   Access to Parameters on an Embedded DSSI controller:

          SET HOST/DUP/DSSI[/BUS:{0:1}] dssi_node_number PARAMS

                   Access to Directory of tools on an Embedded DSSI

          SET HOST/DUP/DSSI[/BUS:{0:1}] dssi_node_number DIRECT

                   Access to Parameters on a KFQSA DSSI controller:

          SHOW UQSSP ! to get port_controller_number PARAMS
          SET HOST/DUP/UQSSP port_controller_number PARAMS

                   These console commands are available on most MicroVAX
                   and VAXstation 3xxx series systems, and most (all?) VAX
                   4xxx series systems. For further information, see the
                   system documentation and-on most VAX systems-see the
                   console HELP text.

                   EK-410AB-MG, _DSSI VAXcluster Installation and
                   Troubleshooting_, is a good resource for setting
                   up a DSSI VMScluster on OpenVMS VAX nodes. (This
                   manual predates coverage of OpenVMS Alpha systems,
                   but gives good coverage to all hardware and software
                   aspects of setting up a DSSI-based VMScluster-and most
                   of the concepts covered are directly applicable to
                   OpenVMS Alpha systems. This manual specifically covers
                   the hardware, which is something not covered by the
                   standard OpenVMS VMScluster documentation.)

                   Also see Section 15.3.3, and for the SCS name of the
                   OpenVMS host see Section 5.7.


                   Information on Networks and Clusters

          15.6.4  How do I rename a DSSI disk (or tape?)

                   If you want to renumber or rename DSSI disks or DSSI
                   tapes, it's easy-if you know the secret incantation...

                   From OpenVMS:

                   $ RUN SYS$SYSTEM:SYSGEN
                   SYSGEN> ^Z
                   PARAMS> STAT CONF
                   <The software version is normally near the top of the display.>
                   PARAMS> EXIT

                   From the console on most 3000- and 4000-class VAX
                   system consoles... (Obviously, the system must be
                   halted for these commands...)

                   Integrated DSSI:

                   SET HOST/DUP/DSSI[/BUS:[0:1]] dssi_node_number PARAMS


                   SET HOST/DUP/UQSSP port_controller_number PARAMS

                   For information on how to get out into the PARAMS
                   subsystem, also see the HELP at the console prompt
                   for the SET HOST syntax, or see the HELP on SET HOST
                   /DUP (once you've connected FYDRIVER under OpenVMS).

                   Once you are out into the PARAMS subsystem, you can
                   use the FORCEUNI option to force the use of the UNITNUM
                   value and then set a unique UNITNUM inside each DSSI
                   ISE-this causes each DSSI ISE to use the specfied unit
                   number and not use the DSSI node as the unit number.
                   Other parameters of interest are NODENAME and ALLCLASS,
                   the node name and the (disk or tape) cluster allocation

                   Ensure that all disk unit numbers used within an
                   OpenVMS Cluster disk allocation class are unique, and
                   all tape unit numbers used within an OpenVMS Cluster
                   tape allocation class are also unique. For details on


 ---------------------------- #include <rtfaq.h> -----------------------------
    For additional, please see the OpenVMS FAQ --
 --------------------------- pure personal opinion ---------------------------
        Hoff (Stephen) Hoffman   OpenVMS Engineering   hoff[at]

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Last Update March 27 2014 @ 02:11 PM