HP OpenVMS Systems Documentation

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The OpenVMS Frequently Asked Questions (FAQ)

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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 controllers.

LANCP> SET 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 disk/tape/controllers/SCSI/widgets?

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.

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 later.

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 later.

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:

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.)

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 device.

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 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 tools.)

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
Pin Description
1 Data Terminal Ready (DTR)
2 Transmit (TXD)
3 Transmit Ground (TXD-)
4 Receive Ground (RXD-)
5 Receive (RXD)
6 Data Set Ready (DSR)

   | 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 vendors.

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.

Table 14-6 PC DB9 Pin-out
Pin Description
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
9 floating

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
Pin Description
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 2000...
9 ...series systems, otherwise left floating.

When pin 8 is shorted to pin 9, this is a BCC08 (or variant) cable, most commonly used as a console cable on the MicroVAX 2000 and VAXstation 2000 series. (Other systems may or may not tolerate connecting pin 8 to pin 9.)

The BN24H looks like this:

     MMJ       RJ45


The BN24J looks like this:

     MMJ       RJ45


Also see:

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 Section

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
Part Converts BC16E MMJ male to fit into
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 connector.
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.
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 connector
H8575-D 25 Pin to MMJ with better ESD Protection
H8575-D 25 Pin to MMJ with better and ESD Protection
H8575-E 25 Pin Integrity rx2600 Management Processor (MP) port to MMJ, with ESD Protection
H8577-AA 6 pin Female MMJ to 8 pin MJ
BC16E-** MMJ cable with connectors, available in various lengths

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 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 again.

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 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 counters.)

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.)

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