=:The OpenVMS Frequently Asked Questions(FAQ)C

The OpenVMS Frequently Asked Questions(FAQ)



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14.24 What is the layout of the VAX floating point format?



CThe VAX floating point format is derived from one of the PDP-11 FP Hformats, which helps explain its strange layout. There are four formats Hdefined: F 32-bit single-precision, D and G 64-bit double-precision and EH 128-bit quadruple precision. For all formats, the lowest addressed F16-bit "word" contains the sign and exponent (and for other Ethan H, some of the most significant fraction bits). Each successive Ghigher-addressed word contains the next 16 lesser-significant fraction Bbits. Bit 15 of the first word is the sign, 1 for negative, 0 for Gpositive. Zero is represented by a biased exponent value of zero and a Dsign of zero; the fraction bits are ignored (but on Alpha, non-zero Cfraction bits in a zero value cause an error.) A value with biased Aexponent zero and sign bit 1 is a "reserved operand" - Ftouching it causes an error - fraction bits are ignored. There are no 1minus zero, infinity, denormalized or NaN values.

HFor all formats, the fraction is normalized and the radix point assumed Cto be to the left of the MSB, hence 0.5 <= f < 1.0. The MSB, Dalways being 1, is not stored. The binary exponent is stored with a Abias varying with type in bits 14:n of the lowest-addressed word.

 

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M  Type    Exponent bits    Exponent bias    Fraction bits (including hidden) M  ========================================================================== 5   F           8                128               24 5   D           8                128               56 5   G          11               1024               53 5   H          15              16384              113 




EThe layout for D is identical to that for F except for 32 additional fraction bits.

CExample: +1.5 in F float is hex 000040C0 (fraction of .11[base 2], biased exponent of 129)i

14.25 Where can I find more info about VAX systems?

s

14.26 Where can I find information on NetBSD for VAX systems?

HGunnar Helliesen maintains a NetBSD VAX FAQ at http://vaxine.bitcon.no/.|

14.27 What system disk size limit on the MicroVAX and VAXstation 3100?



CSystem disks larger than 1.073 gigabytes (GB)---1fffff hexidecimal Hblocks -- are not supported on any member of the VAXstation 3100 series Fand on certain older members of the MicroVAX 3100 series, and are not Hreliable on these affected systems. (See below to identify the affected Fsystems---the more recent members of the MicroVAX 3100 series systems are NOT affected.)

FVarious of the SCSI commands used by the boot drivers imbedded in the Hconsole PROM on all members of the VAXstation 3100 series use "Group 0" Gcommands, which allow a 21 bit block number field, which allows access Fto the first 1fffff hexidecimal blocks of a disk. Any disk references Epast 1fffff will wrap---this wrapping behaviour can be of particular Ginterest when writing a system crashdump file, as this can potentially Flead to system disk corruptions should any part of the crashdump file be located beyond 1.073 GB.

CMore recent systems and console PROMs use "Group 1" SCSI commands, (which allow a 32 bit block number field.

EThere was a similar limitation among the oldest of the MicroVAX 3100 Hseries, but a console boot PROM was phased into production and was made Havailable for field retrofits---this PROM upgrade allows the use of the D"Group 1" SCSI commands, and thus larger system disks. There was no 4similar PROM upgrade for the VAXstation 3100 series.

(Systems that are affected by this limit:



>Also see http://www.whiteice.com/~williamwebb/intro/DOC-i.html

9Also see Section 9.5.^

14.28 What are the VMB boot flag values?



DThe following flags are passed (via register R5) to the OpenVMS VAX Dprimary bootstrap image VMB.EXE. These flags control the particular behaviour of the bootstrap:

FThe exact syntax is console-specific, recent VAX consoles tend to use the following:

 

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  >>> BOOT/R5:flags  @  Bit     Meaning                                               @  ---     -------                                               N                                                                              @   0      RPB$V_CONV                                            @          Conversational boot. At various points in the         @          system boot procedure, the bootstrap code             @          solicits parameter and other input from the           @          console terminal.  If the DIAG is also on then        @          the diagnostic supervisor should enter "MENU"         @          mode and prompt user for the devices to test.          @   1      RPB$V_DEBUG                                           @          Debug.  If this flag is set, VMS maps the code        @          for the XDELTA debugger into the system page          @          tables of the running system.                         @                                                                @   2      RPB$V_INIBPT                                          @          Initial breakpoint. If RPB$V_DEBUG is set, VMS        @          executes a BPT instruction immediately after          @          enabling mapping.                                     ?                                                               @   3      RPB$V_BBLOCK                                          @          Secondary boot from the boot block.  Secondary        @          bootstrap is a single 512-byte block, whose LBN       @          is specified in R4.                                   @                                                                @   4      RPB$V_DIAG                                            @          Diagnostic boot.  Secondary bootstrap is image        @          called [SYSMAINT]DIAGBOOT.EXE.                        @                                                                @   5      RPB$V_BOOBPT                                          @          Bootstrap breakpoint. Stops the primary and           @          secondary bootstraps with a breakpoint                @          instruction before testing memory.                     @   6      RPB$V_HEADER                                          @          Image header. Takes the transfer address of the       @          secondary bootstrap image from that file's            @          image header.  If RPB$V_HEADER is not set,            @          transfers control to the first byte of the            @          secondary boot file.                                  @                                                                @   7      RPB$V_NOTEST                                          @          Memory test inhibit. Sets a bit in the PFN bit        @          map for each page of memory present.  Does not        @          test the memory.                                      @                                                                @   8      RPB$V_SOLICT                                          @          File name. VMB prompts for the name of a              @          secondary bootstrap file.                             @                                                                @   9      RPB$V_HALT                                            @          Halt before transfer.  Executes a HALT                @          instruction before transferring control               @          to the secondary bootstrap.                           @                                                                @  10      RPB$V_NOPFND                                          @          No PFN deletion (not implemented; intended to         @          tell VMB not to read a file from the boot device      @          that identifies bad or reserved memory pages,         @          so that VMB does not mark these pages as valid        @          in the PFN bitmap).                                   @                                                                @  11      RPB$V_MPM                                             @          Specifies that multi-port memory is to be used        @          for the total EXEC memory requirement.  No local      @          memory is to be used.  This is for tightly-coupled    @          multi-processing.  If the DIAG is also on, then       @          the diagnostic supervisor enters "AUTOTEST" mode.     @                                                                @  12      RPB$V_USEMPM                                          @          Specifies that multi-port memory should be used in    @          addition to local memory, as though both were one     @          single pool of pages.                                 @                                                                @  13      RPB$V_MEMTEST                                         @          Specifies that a more extensive algorithm be used     @          when testing main memory for hardware                 @          uncorrectable (RDS) errors.                           @                                                                @  14      RPB$V_FINDMEM                                         @          Requests use of MA780 memory if MS780 is              @          insufficient for booting.  Used for 11/782            @          installations.                                        @                                                                F  <31:28> RPB$V_TOPSYS                                          @          Specifies the top level directory number for          @          system disks with multiple systems.                    


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14.29 What is the Accuracy of VAX the Time of Year (TOY) Clock?



FThe VAX Time-Of-Year (TOY) clock (used to save the time over a reboot For power failure) is specified as having an accuracy of 0.0025%. This +is a drift of roughly 65 seconds per month.

GThe VAX Interval Time is used to keep the running time, and this has a Bspecified accuracy of .01%. This is a drift of approximately 8.64 Hseconds per day. Any high-IPL activity can interfere with the IPL 22 or 6IPL 24 (this depends on the VAX implementation) clock Finterrupts---activities such as extensive device driver interrupts or *memory errors are known to slow the clock.

nAlso see Section 14.14, Section 4.3.r

14.30 Which serial port is the console on the MicroVAX 3100?



HJust to keep life interesting, the MicroVAX 3100 has some "interesting" Bconsole ports behaviours based on the setting of the BREAK enable Fswitch. When the console is not enabled to respond to BREAK, MMJ-1 is Ethe console port. MMJ-3 will (confusingly) output the results of the Hselftest in parallel with MMJ-1. When the console is enabled to respond Gto BREAK, MMJ-3 becomes the console port, and MMJ-1 will (confusingly) 6output the results of selftest in parallel with MMJ-3.s

14.31 How can I set up an alternate console on a VAXstation?



HMost VAXstation systems have a switch---often labeled S3---that enables .one of the serial lines as the system console.

AVarious members of the DEC 3000 series Alpha systems also have a Bsimilarly-labled S3 switch for selection of the alternate console.

¦Also see Section 14.4, Section 11.11, and Section 14.37.d

14.32 What are the VAX processor (CPU) codes?



 

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   CPU:    Platform:    -----   --------- *   KA41-A : MicroVAX 3100 Model 10 and 20 +   KA41-B : VAXserver 3100 Model 10 and 20    KA41-C : InfoServer ,   KA41-D : MicroVAX 3100 Model 10e and 20e -   KA41-E : VAXserver 3100 Model 10e and 20e ,   KA42-A : VAXstation 3100 Model 30 and 40 ,   KA42-B : VAXstation 3100 Model 38 and 48 %   KA43-A : VAXstation 3100 Model 76 *   KA45   : MicroVAX 3100 Model 30 and 40 %   KA46   : VAXstation 4000 Model 60 #   KA47   : MicroVAX 3100 Model 80     KA48   : VAXstation 4000 VLC )   KA49-A : VAXstation 4000 Model 90/90A %   KA49-B : VAXstation 4000 Model 95 %   KA49-C : VAXstation 4000 Model 96 #   KA50   : MicroVAX 3100 Model 90 #   KA51   : MicroVAX 3100 Model 95    KA52   : VAX 4000 Model 100    KA53   : VAX 4000 Model 105    KA54   : VAX 4000 Model 106 #   KA55   : MicroVAX 3100 Model 85 #   KA56   : MicroVAX 3100 Model 96    KA57   : VAX 4000 Model 108 #   KA58   : MicroVAX 3100 Model 88 #   KA59   : MicroVAX 3100 Model 98    KA85   : VAX 8500    KA86   : VAX 8600    KA88   : VAX 8800 '   KA600  : VAX 4000-50 (aka VAXbrick) 0   KA610  : MicroVAX I, VAXstation I (aka KD32)    KA620  : rtVAX (VAXeln)    KA62A  : VAX 6000-200    KA62B  : VAX 6000-300 '   KA630  : MicroVAX II, VAXstation II )   KA640  : MicroVAX 3300, MicroVAX 3400 H   KA650  : VAXstation 3200, MicroVAX 3500, MicroVAX 3600, MicroVAX III    KA64A  : VAX 6000-400 8   KA655  : MicroVAX 3800, MicroVAX 3900, MicroVAX III+    KA65A  : VAX 6000-500 (   KA660  : VAX 4000-200, VAX 4 upgrade    KA66A  : VAX 6000-600    KA670  : VAX 4000-300    KA675  : VAX 4000-400    KA680  : VAX 4000-500    KA681  : VAX 4000-500A    KA690  : VAX 4000-600    KA691  : VAX 4000-605A    KA692  : VAX 4000-700A    KA693  : VAX 4000-605A    KA694  : VAX 4000-705A    KA730  : VAX-11/730    KA750  : VAX-11/750 #   KA780  : VAX-11/780, VAX-11/782    KA785  : VAX-11/785    KA7AA  : VAX 7000-600    KA7AB  : VAX 7000-700    KA7AC  : VAX 7000-800    KA800  : VAXrta    KA820  : VAX 8200, VAX 8300    KA825  : VAX 8250, VAX 8350    KA865  : VAX 8650 


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14.33 OpenVMS is porting to Intel IA-64?



AYes, OpenVMS is being ported to the Intel IA-64 architecture; to 4systems based on the Intel Itanium Processor Family.g

14.34 Where can I get Intel Itanium information?



EIntel Itanium Processor Family Architecture, Hardware, software, and #related materials are available at:



EThe Intel Extensible Firmware Interface (EFI) console documentation: .http://www.pentium.de/technology/efi/index.htmw

14.35 Where can I get software and hardware support information?



<Please contact the HP Customer Support Center. Services and Ginformation, manuals, guides, downloads, and various other information is available at:



:Various hardware and system documentation is available at:



CTSM (Terminal Server Manager), DEChub, DECserver, etc. information:

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14.36 Where can I get hardware self-maintenance support assistance?



CThe HP Assisted Services (CAS) program (a direct descendent of the Hprogram once known as DECmailer) is available to customers that wish to Dmaintain their own system(s) (self-maintenance), but that wish some Clevel of assistance in acquiring hardware diagnostics and hardware Fmanuals for the system(s), and that wish to have access to spares and Bmodule-level repairs for customer-performed hardware module swaps:

}

14.37 Why does my system halt when I power-cycle the console terminal?



AVarious VAX and Alpha consoles are designed to process the BREAK &signal, treating it as a HALT request.

>A BREAK is a deliberately-generated serial line framing error.

EWhen a serial line device such as a terminal powers up (or sometimes Bwhen powering down) it can generate framing errors. These framing 0errors are indistingushable from a BREAK signal.

BWhen a BREAK is received on a serial line console for various VAX Hsystems---including most VAXstation, MicroVAX, and VAX 4000 series---it Bis typically interpreted as a HALT. Alpha systems will also often 9process a BREAK in a similar fashion, halting the system.

?There is no uniform or generally-available way to disable this ?behaviour on every VAX or Alpha system. On some systems, BREAK Dprocessing can be disabled in favor of [CTRL/P], or [CTRL/P] is the only way to halt the processor.

GThe most common way to avoid these halts is to disable the serial line Dconsole or to simply not power-cycle the console terminal. There is Ecertain important system state information that is displayed only on Athe console, OpenVMS expects to always have access to the system console.

9Also see Section 5.5.t

14.38 Can I reuse old keyboards, mice and monitors with a PC?



COlder HP keyboards (those with the DIGITAL logo and the RJ modular Cjacks), older HP mice (those with the DIGITAL logo and with the RJ Dmodular jacks, or with a DIN connector with pins in a configuration Eother than the PC-standard DIN connector pin orientation), and older Avideo monitors (with RGB synch-on-green video signaling) all use Gsignaling formats and/or communications protocols that differ from the ?PC standards, and are not (easily) interchangable nor (easily) Hcompatible with typical PC peripheral device controllers. LK201, LK401, AVSXXX, VR260, VR290, etc., are incompatible with most PC systems.

ENewer HP (and Compaq) keyboards (those with with PC-style DIN plugs, Dand the HP, Compaq or DIGITAL logo), newer HP mice (with PC-pin DIN Eplugs, and the HP, Compaq or DIGITAL logo), and newer video monitors D(multi-synch) are often interchangeable with "industry standard" PC >systems, and can often be used with most PC peripheral device Hcontrollers. LK461, LK471, PC7XS-CA, VRC16, VRC21, etc., are compatible with most PC systems.

HRule of thumb: if the peripheral device component was sold for use with Ethe DEC 2000 (DECpc 150 AXP), an AlphaServer series, an AlphaStation Eseries, or more recent Alpha system, it will probably work with a PC Gperipheral controller. If the peripheral device component was sold for Duse with an VT420 or older terminal, most VAX, most VAXstation, and 1most Alpha systems with names in the format `DEC ;<four-digit-number>', it probably won't work on a PC.

FNote that the above is a general guideline, and should not be read to Hindicate that any particular peripheral device will or will not work in Eany particular configuration, save for those specific configurations &the device is explicitly supported in.

GSoftware Integrators sells a video adapter card called Gemini P1 which Hwill drive many of the older HP (DIGITAL-logo) fixed-frequency monitors on a PC system:



EThe DIGITAL part number 29-32540-01 converts the output from the RGB Fcable (3 BNC, synch-on-green) that comes with the VAXstation 3100 and 4VAXstation 4000 series to a female SVGA D connector.

@This will allow PC Multisync monitors with the needed frequency Cspecifications to be used with the VAXstations. It may work with a >VAXstation 2000 series, but I have not tried that combination.

?The protocol definition for the old DIGITAL keyboard and mouse @interfaces is buried at the back of the QDSS section in the old CVAXstation II manual, specifically, in the back of the VCB02 Video BSubsystem Technical Manual (EK-104AA-TM). The keyboard wiring and Hprotocol is in appendix B, and occupies circa 44 pages. The mouse is in appendix C, circa 12 pages.

;Also see Section 14.39.v

14.39 Which video monitor works with which graphics controller?



G To determine the answer to the "will this video monitor or this G LCD panel work with this graphics controller?" question, please > first locate the resolution(s) and the frequencies that are I possible/supported at both ends of the video cable (on the display and E on the graphics controller, in other words), and then determine if C there are any matching settings available. If there are multiple H matches, you will need to determine which one is most appropriate for your needs.

AYou will also need to determine if the video monitor or graphics Acontroller requires the 3 BNC signaling with the synchronization Gsignals on the green wire, or the 5 BNC signalling common on many PCs, Gor other connections such as the DB15 video connector or USB connector used on various systems.

HIf there are no matches, you will likely need to change the hardware at &one or both ends of the "video cable".

=The refresh frequencies for many devices have been posted to Fcomp.os.vms and/or other newsgroups. Search the archives for details. Also see:



;Also see Section 14.38.m

14.40 Where can I get information on storage hardware?



CInformation on various HP (Compaq, DIGITAL) OpenVMS and other disk Gstorage hardware and controllers, and related technical information on ,SCSI, device jumpers, etc., is available at:

p

14.41 Why does my LK401 keyboard unexpectedly autorepeat?



#There are several modes of failure:

~

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



CCheck the firmware revision on the keyboard. Hardware revision B01 Fintroduced an incompatability with the device driver which causes the Gkeyboard to not be recognized correctly. There is a patch available to Hfix this problem: [AXPDRIV06_061] - the fix is also included in OpenVMS GV6.2. The rev A01 keyboard, and the LK450 should work without problems.

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




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