Tim,

The RSTS TAP image is definitely not a TPC image -- it is valid SIMH format 
except for the strangeness at the end.  (My MTD image format is the same as the 
TPC format description I found at 
ftp://ftp.mrynet.com/operatingsystems/simulators/simtools/mtcvtv23/mtcvtv23.txt,
 but using Fortran unformatted file format instead of an unstructured 
byte-stream file format.)  Do you think the likely culprit that created the 
flawed TAP image might have been mtcvtv23?

Larry Baker
US Geological Survey
650-329-5608
[email protected]



On 24 May 2014, at 3:18 PM, Shoppa, Tim wrote:

> Whenever I imaged a tape using VMSTPC I named the TPC image ".TPC" and then 
> (decade or later in the 90's) often converted to SIMH .TAP.
> 
> Others name the TPC as ".TAP" which can be a little vague. If it was made in 
> early 90's or earlier it is likely TPC even if it ends with .TAP.
> 
> There is a SIMH utility program for converting TPC to TAP, it is called 
> mtcvtv23 (or similar)
> 
> Tim
>  
> From: Larry Baker [mailto:[email protected]] 
> Sent: Saturday, May 24, 2014 05:42 PM
> To: simh <[email protected]> 
> Subject: [Simh] Some TAP image files aren't quite right 
>  
> While I've been helping Cory to copy his TAP mag tape image file to a real 
> TK50, I've discovered that the TAP image he's been using does not correctly 
> follow Bob Supnik's SIMH Magtape Representation and Handling document 
> (http://simh.trailing-edge.com/docs/simh_magtape.pdf).  I don't know how SIMH 
> TAP images get created.  But, if there is a common tool that is being used, 
> it might need some tweaking.
> 
> The SIMH TAP image Cory is using is rstse_v10_1_install_sep10_1992.tap.  I 
> downloaded it from 
> ftp://ftp.trailing-edge.com/pub/rsts_dists/rstse_v10_1_install_sep10_1992.tap.bz2.
>   The SIMH2MTD conversion program I wrote for Cory converts a SIMH TAP file 
> to my own MTD magtape image file format, with which he can then run my MTD 
> program to make a real TK50 from the MTD image.  The conversion program 
> validates the SIMH TAP format and returns a Fatal Hardware Error 
> pseudo-magtape status when the format is incorrect.  This happens at the end 
> of the rstse_v10_1_install_sep10_1992.tap SIMH TAP file.  Running a debugging 
> version of SIMH2MTD shows that there is an illegal metadata marker after the 
> two tape marks at the end of the tape:
> 
>> DO_CONVERT: Metadata = 00000050, ierr =     0   <--- This is an ANSI EOF1 
>> label
>> DO_CONVERT: Metadata = 00000050, ierr =     0   <--- This is an ANSI EOF2 
>> label
>> DO_CONVERT: Metadata = 00000000, ierr =     0   <--- Tape Mark
>> DO_CONVERT: SIMH Tape Mark
>> DO_CONVERT: Metadata = 00000000, ierr =     0   <--- Tape Mark
>> DO_CONVERT: SIMH Tape Mark
>> DO_CONVERT: Metadata = 0000FFFF, ierr =     0   <--- Looks like a recl for a 
>> 65535 byte data record, but there are not 65536 (incl. padding) + 4 (recl 
>> copy) bytes left in the file
>> Fortran Run-Time error:          140
>> %SYSTEM-F-DRVERR, fatal drive error
>> %TRACE-F-TRACEBACK, symbolic stack dump follows
>> module name     routine name                     line       rel PC    abs PC
>> 
>> DO_CONVERT      DO_CONVERT                       1509      0000021E  00011496
>> SIMH2MTD        SIMH2MTD                         1424      00000017  00010E17
> 
> 
> Sure enough, if I dump the file from my Mac, where I downloaded it and 
> uncompressed it, I can see there's garbage at the end of the file (ffff 0000 
> ... ffff 0000):
> 
>> savaii:Downloads baker$ ls -l rstse_v10_1_install_sep10_1992.tap
>> -rw-r--r--  1 baker  GS\domain users  24096588 Oct 30  2004 
>> rstse_v10_1_install_sep10_1992.tap
> 
> 
>> savaii:Downloads baker$ od -A d -x -j 24085504 
>> rstse_v10_1_install_sep10_1992.tap | more
>> 24085504      addf    acba    abba    addf    abba    adaa    dfb1    b0bc
>> 24085520      babb    f6f6    dfdf    dfdf    dfdf    d9df    f5f2    f6a3
>> 24085536      baab    aba7    dfdb    dfc2    bab3    abb9    b7d7    4c2f
>> 24085552      2e44    4554    5458    2c24    3432    2534    2029    2020
>> 24085568      2021    4553    444e    4620    5249    5453    3220    3534
>> 24085584      4320    4148    4152    5443    5245    0953    2020    0030
>> 24085600      0000    0000    0000    0000    0000    0000    0000    0000
>> *
>> 24085648      0000    0000    0000    0000    0000    0000    0000    2000
>> 24085664      0000    0000    0000    0050    0000    4f45    3146    3233
>> 24085680      3137    422e    4b43    2020    2020    2020    2020    4220
>> 24085696      4341    554b    3050    3030    3031    3430    3036    3030
>> 24085712      3031    2030    3239    3232    2033    3239    3232    2033
>> 24085728      3030    3030    3630    4544    5243    5453    2f53    2045
>> 24085744      2020    2020    2020    2020    2020    0050    0000    0050
>> 24085760      0000    4f45    3246    3046    3138    3239    3830    3931
>> 24085776      2032    2020    2020    2020    2020    2020    2020    2020
>> 24085792      2020    2020    2020    204d    2020    2020    2020    2020
>> 24085808      2020    2020    3030    2020    2020    2020    2020    2020
>> 24085824      2020    2020    2020    2020    2020    2020    2020    2020
>> 24085840      2020    0050    0000    0000    0000    0000    0000    ffff
>> 24085856      0000    0000    0000    0000    0000    0000    0000    0000
>> *
>> 24096576      0000    0000    0000    0000    ffff    0000                
>> 24096588
> 
> Not all SIMH TAP images are like this.  The RSX-11M-Plus SIMH TAP I 
> downloaded from 
> http://bitsavers.trailing-edge.com/bits/DEC/pdp11/magtapes/rsx11mplus/BB-3077D-SC_RSX-11M+_V3.0_SRC_1985.tap
>  has its Unix EOF in the right spot:
> 
>> savaii:Downloads baker$ ls -l BB-3077D-SC_RSX-11M+_V3.0_SRC_1985.tap
>> -rw-r--r--  1 baker  GS\domain users  9966532 May 18 22:12 
>> BB-3077D-SC_RSX-11M+_V3.0_SRC_1985.tap
> 
>> savaii:Downloads baker$ od -A d -x -j 9966500 
>> BB-3077D-SC_RSX-11M+_V3.0_SRC_1985.tap
>> 9966500      2020    2020    2020    2020    2020    2020    2020    2020
>> 9966516      2020    2020    0050    0000    0000    0000    0000    0000
>> 9966532
> 
> 
> The 0050 0000 is the 80 decimal recl copy from the last data record (as ANSI 
> EOF2 label), which is followed by two tape marks (0000 0000), and the Unix 
> EOF.
> 
> I can deal with this, but if anyone knows where the buggy SIMH TAP images 
> come from, that should be fixed.
> 
> Larry Baker
> US Geological Survey
> 650-329-5608
> [email protected]
> 
> 
> 

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