[Simh] VAX Tape Emulation?

[Zane Healy]

> On Feb 20, 2018, at 1:58 PM, Mark Pizzolato <Mark at infocomm.com> wrote:
> 
> I would actually attribute the 'improved' behavior to the fact that tape I/O to TQ 
> and XQ devices is asynchronous in the latest code.
> 
> I would seriously consider Mr Baker's suggestion of backing up to simh disks.  Not to save sets, but to merely using VMS backup to perform BACKUP/Image to RQ units attached to disk container files.  Thus allowing any recovery you might need to have random access to the original file system without having to dig through a save set sequentially.
> 
> An industrious fellow might also want to manage the RQ media setup and change activities automatically from the AXP system with a program that does a TCP connect to a simh Remote Console.
> 
> - Mark

Based on the documentation, the TQ device appears to be limited to 2000GB.  As a result I’ve been using the TS device.

Realistically, once I get these “tapes” created, I’ll be migrating part of the data from physical disks on the Alpha, to disks on SIMH/VAX.  I’ve already done some experimentation with that.  Unfortunately I have ODS-5 data, and some software requires an Alpha.

Okay…  Some more info on the crashes I’m seeing.  The first is specific to the current source in GitHub.  It seems pretty obvious at this point that I can write a tape from the Alpha, to a virtual SIMH VAX tape drive, but trying to read the data crashes the SIMH VAX.

This command started, got about half way through, and then the terminal session on my Alpha that I was running this on was reset.  The backup did not complete.
backup/verify/list $1$DKC300:[000000...]*.*;* tape:A0005


Running this from the Alpha, crashes VAX, once it goes to Verify.  This happened on both V3.8-1 and on Current. 
backup/verify $1$DKC300:[000000...]*.*;* tape:A0005
%MOUNT-I-MOUNTED, A0004 mounted on _$5$MSA0: (RENNY)
%BACKUP-I-STARTVERIFY, starting verification pass at 21-FEB-2018 00:11:02.08
%BACKUP-F-POSITERR, error positioning _$5$MSA0:[]A0005.;
-SYSTEM-F-VOLINV, volume is not software enabled


Partial output from the Console of the VAX.  If you look further down, you’ll see the full output from trying to read a tape.

SYSGETSYI.EXE                          8344EA00 83450A00
SYSDEVICE.EXE                          83450E00 83453800
MESSAGE_ROUTINES.EXE                   83453E00 8345A000
EXCEPTION.EXE                          8346A600 83474E00
LOGICAL_NAMES.EXE                      83475600 83498E00
SECURITY.EXE                           83499800 834A3200
LOCKING.EXE                            834A3A00 834AA800
PAGE_MANAGEMENT.EXE                    834AB200 834B5200
WORKING_SET_MANAGEMENT.EXE             834CA000 834CFE00
IMAGE_MANAGEMENT.EXE                   834D0800 834D3E00
EVENT_FLAGS_AND_ASTS.EXE               834D4400 834D6600
IO_ROUTINES.EXE                        834D7000 834E7600
PROCESS_MANAGEMENT.EXE                 834E9000 834F6A00
ERRORLOG.EXE                           83560200 83560E00
PRIMITIVE_IO.EXE                       83561400 83562600
SYSTEM_SYNCHRONIZATION_UNI.EXE         83562A00 83566E00
SYSTEM_PRIMITIVES_MIN.EXE              83567400 8356B200

**** Starting memory dump, writing dump to unit number 0
. . . . . . .
**** Memory dump complete, dump written  to unit number 0

HALT instruction, PC: 83C4D909 (MOVB 400(R1),R0)
sim> q




Okay, here is the crash from when I tried to read a tape from the Alpha.  I’m not sure if this is a cluster issue, or a SIMH issue.  I could test this with real hardware, but it would take quite a bit of time to dig out all the bits, assuming they still work.


**** Fatal BUG CHECK, version = V7.3     CLUEXIT, Node voluntarily exiting VAXcluster

    Crash CPU: 00        Primary CPU: 00

    Active/available CPU masks: 00000001/00000001

    Current process = NULL

    Register dump

        R0 = 0000204C
        R1 = 0000800A
        R2 = 00000000
        R3 = 83AA28C0
        R4 = 83A6B780
        R5 = 83AA2A40
        R6 = 00000000
        R7 = 000000DE
        R8 = 83A6E080
        R9 = 83A9C080
        R10= 83A6F000
        R11= 7FFB9F0A
        AP = 7FF6D558
        FP = 7FF6D534
        SP = 84595574
        PC = 83C395E6
        PSL= 04080004

    Kernel/interrupt/boot stack

        8459557C  0000204C
        84595580  0000800A
        84595584  83C391F1
        84595588  83A5F4A3
        8459558C  83A6B780
        84595590  83A5FF0E
        84595594  83A6B780
        84595598  83A60B95
        8459559C  83B61CC0
        845955A0  83B7D140
        845955A4  83A6F1F0
        845955A8  83A9C2C0
        845955AC  83A615C7
        845955B0  83A60C25
        845955B4  83A6E098
        845955B8  84594210
        845955BC  00000034
        845955C0  00003778
        845955C4  7FFB9E80
        845955C8  7FFB9F3E
        845955CC  7FFB9F0A
        845955D0  7FF6D558
        845955D4  83567ED2
        845955D8  0000003E
        845955DC  00000000
        845955E0  00000009
        845955E4  84594000
        845955E8  83B7A200
        845955EC  848CC400
        845955F0  0000C6E8
        845955F4  00000000
        845955F8  834E9F8D
        845955FC  04C30000


    Loaded images 

[SYSMSG]SYSMSG.EXE                     83331200 83377C00
[SYS$LDR]SYSLDR_DYN.EXE                8356EA00 83570A00
[SYS$LDR]DDIF$RMS_EXTENSION.EXE        83570E00 83572000
[SYS$LDR]RECOVERY_UNIT_SERVICES.EXE    83572200 83572A00
[SYS$LDR]RMS.EXE                       83377E00 833A4800
SYS$NTA.EXE                            833ED400 833ED600
VAXCLUSTER_CACHE.EXE                   833EDA00 833F2600
SYS$NETWORK_SERVICES.EXE               833F2C00 833F2E00
SYS$UTC_SERVICES.EXE                   833F3400 833F4200
SYS$TRANSACTION_SERVICES.EXE           833F4800 83402600
SYS$IPC_SERVICES.EXE                   83402A00 83420A00
CPULOA.EXE                             83420C00 83426000
LMF$GROUP_TABLE.EXE                    83428400 83429E00
SYSLICENSE.EXE                         8342A200 8342D400
F11BXQP.EXE                            8342D800 8344D000
SNAPSHOT_SERVICES.EXE                  8344D800 8344E400
SYSGETSYI.EXE                          8344EA00 83450A00
SYSDEVICE.EXE                          83450E00 83453800
MESSAGE_ROUTINES.EXE                   83453E00 8345A000
EXCEPTION.EXE                          8346A600 83474E00
LOGICAL_NAMES.EXE                      83475600 83498E00
SECURITY.EXE                           83499800 834A3200
LOCKING.EXE                            834A3A00 834AA800
PAGE_MANAGEMENT.EXE                    834AB200 834B5200
WORKING_SET_MANAGEMENT.EXE             834CA000 834CFE00
IMAGE_MANAGEMENT.EXE                   834D0800 834D3E00
EVENT_FLAGS_AND_ASTS.EXE               834D4400 834D6600
IO_ROUTINES.EXE                        834D7000 834E7600
PROCESS_MANAGEMENT.EXE                 834E9000 834F6A00
ERRORLOG.EXE                           83560200 83560E00
PRIMITIVE_IO.EXE                       83561400 83562600
SYSTEM_SYNCHRONIZATION_UNI.EXE         83562A00 83566E00
SYSTEM_PRIMITIVES_MIN.EXE              83567400 8356B200

**** Starting memory dump, writing dump to unit number 0 
. . . . . . . 
**** Memory dump complete, dump written  to unit number 0 

HALT instruction, PC: 83C4D909 (MOVB 400(R1),R0)
sim> 


End Result, I think I’m going to have to resort to the disk solution.

Zane