<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">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 (<a href="http://simh.trailing-edge.com/docs/simh_magtape.pdf">http://simh.trailing-edge.com/docs/simh_magtape.pdf</a>). 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.<div><br></div><div>The SIMH TAP image Cory is using is rstse_v10_1_install_sep10_1992.tap. I downloaded it from <a href="ftp://ftp.trailing-edge.com/pub/rsts_dists/rstse_v10_1_install_sep10_1992.tap.bz2">ftp://ftp.trailing-edge.com/pub/rsts_dists/rstse_v10_1_install_sep10_1992.tap.bz2</a>. 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:</div><div><br></div><div><blockquote type="cite"><div><font class="Apple-style-span" color="#000000">DO_CONVERT: Metadata = 00000050, ierr = 0 <--- This is an ANSI EOF1 label</font></div><div><font class="Apple-style-span" color="#000000">DO_CONVERT: Metadata = 00000050, ierr = 0 <--- This is an ANSI EOF2 label</font></div><div><font class="Apple-style-span" color="#000000">DO_CONVERT: Metadata = 00000000, ierr = 0 <--- Tape Mark</font></div><div><font class="Apple-style-span" color="#000000">DO_CONVERT: SIMH Tape Mark</font></div><div><font class="Apple-style-span" color="#000000">DO_CONVERT: Metadata = 00000000, ierr = 0 <--- Tape Mark</font></div><div><font class="Apple-style-span" color="#000000">DO_CONVERT: SIMH Tape Mark</font></div><div><font class="Apple-style-span" color="#000000">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</font></div><div><font class="Apple-style-span" color="#000000">Fortran Run-Time error: 140</font></div><div><font class="Apple-style-span" color="#000000">%SYSTEM-F-DRVERR, fatal drive error</font></div><div><font class="Apple-style-span" color="#000000">%TRACE-F-TRACEBACK, symbolic stack dump follows</font></div><div><font class="Apple-style-span" color="#000000">module name routine name line rel PC abs PC</font></div><div><font class="Apple-style-span" color="#000000"><br></font></div><div><font class="Apple-style-span" color="#000000">DO_CONVERT DO_CONVERT 1509 0000021E 00011496</font></div><div><font class="Apple-style-span" color="#000000">SIMH2MTD SIMH2MTD 1424 00000017 00010E17</font></div></blockquote></div><div><div><br></div></div><div>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):</div><div><br></div><div><blockquote type="cite"><div><font class="Apple-style-span" color="#000000">savaii:Downloads baker$ ls -l rstse_v10_1_install_sep10_1992.tap</font></div><div><font class="Apple-style-span" color="#000000">-rw-r--r-- 1 baker GS\domain users 24096588 Oct 30 2004 rstse_v10_1_install_sep10_1992.tap</font></div></blockquote></div><div><div><br></div></div><div><blockquote type="cite"><div><font class="Apple-style-span" color="#000000">savaii:Downloads baker$ od -A d -x -j 24085504 rstse_v10_1_install_sep10_1992.tap | more</font></div><div><font class="Apple-style-span" color="#000000">24085504 addf acba abba addf abba adaa dfb1 b0bc</font></div><div><font class="Apple-style-span" color="#000000">24085520 babb f6f6 dfdf dfdf dfdf d9df f5f2 f6a3</font></div><div><font class="Apple-style-span" color="#000000">24085536 baab aba7 dfdb dfc2 bab3 abb9 b7d7 4c2f</font></div><div><font class="Apple-style-span" color="#000000">24085552 2e44 4554 5458 2c24 3432 2534 2029 2020</font></div><div><font class="Apple-style-span" color="#000000">24085568 2021 4553 444e 4620 5249 5453 3220 3534</font></div><div><font class="Apple-style-span" color="#000000">24085584 4320 4148 4152 5443 5245 0953 2020 0030</font></div><div><font class="Apple-style-span" color="#000000">24085600 0000 0000 0000 0000 0000 0000 0000 0000</font></div><div><font class="Apple-style-span" color="#000000">*</font></div><div><font class="Apple-style-span" color="#000000">24085648 0000 0000 0000 0000 0000 0000 0000 2000</font></div><div><font class="Apple-style-span" color="#000000">24085664 0000 0000 0000 0050 0000 4f45 3146 3233</font></div><div><font class="Apple-style-span" color="#000000">24085680 3137 422e 4b43 2020 2020 2020 2020 4220</font></div><div><font class="Apple-style-span" color="#000000">24085696 4341 554b 3050 3030 3031 3430 3036 3030</font></div><div><font class="Apple-style-span" color="#000000">24085712 3031 2030 3239 3232 2033 3239 3232 2033</font></div><div><font class="Apple-style-span" color="#000000">24085728 3030 3030 3630 4544 5243 5453 2f53 2045</font></div><div><font class="Apple-style-span" color="#000000">24085744 2020 2020 2020 2020 2020 0050 0000 0050</font></div><div><font class="Apple-style-span" color="#000000">24085760 0000 4f45 3246 3046 3138 3239 3830 3931</font></div><div><font class="Apple-style-span" color="#000000">24085776 2032 2020 2020 2020 2020 2020 2020 2020</font></div><div><font class="Apple-style-span" color="#000000">24085792 2020 2020 2020 204d 2020 2020 2020 2020</font></div><div><font class="Apple-style-span" color="#000000">24085808 2020 2020 3030 2020 2020 2020 2020 2020</font></div><div><font class="Apple-style-span" color="#000000">24085824 2020 2020 2020 2020 2020 2020 2020 2020</font></div><div><font class="Apple-style-span" color="#000000">24085840 2020 0050 0000 0000 0000 0000 0000 ffff</font></div><div><font class="Apple-style-span" color="#000000">24085856 0000 0000 0000 0000 0000 0000 0000 0000</font></div><div><font class="Apple-style-span" color="#000000">*</font></div><div><font class="Apple-style-span" color="#000000">24096576 0000 0000 0000 0000 ffff 0000 </font></div><div><font class="Apple-style-span" color="#000000">24096588</font></div></blockquote><div><div><br></div></div><div>Not all SIMH TAP images are like this. The RSX-11M-Plus SIMH TAP I downloaded from <a href="http://bitsavers.trailing-edge.com/bits/DEC/pdp11/magtapes/rsx11mplus/BB-3077D-SC_RSX-11M+_V3.0_SRC_1985.tap">http://bitsavers.trailing-edge.com/bits/DEC/pdp11/magtapes/rsx11mplus/BB-3077D-SC_RSX-11M+_V3.0_SRC_1985.tap</a> has its Unix EOF in the right spot:</div><div><br></div><div><blockquote type="cite"><div><font class="Apple-style-span" color="#000000">savaii:Downloads baker$ ls -l BB-3077D-SC_RSX-11M+_V3.0_SRC_1985.tap</font></div><div><font class="Apple-style-span" color="#000000">-rw-r--r-- 1 baker GS\domain users 9966532 May 18 22:12 BB-3077D-SC_RSX-11M+_V3.0_SRC_1985.tap</font></div><div></div></blockquote><br><blockquote type="cite"><div><font class="Apple-style-span" color="#000000">savaii:Downloads baker$ od -A d -x -j 9966500 BB-3077D-SC_RSX-11M+_V3.0_SRC_1985.tap</font></div><div><font class="Apple-style-span" color="#000000">9966500 2020 2020 2020 2020 2020 2020 2020 2020</font></div><div><font class="Apple-style-span" color="#000000">9966516 2020 2020 0050 0000 0000 0000 0000 0000</font></div><div><font class="Apple-style-span" color="#000000">9966532</font></div></blockquote></div><div><div><br></div></div><div>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.</div><div><br></div><div>I can deal with this, but if anyone knows where the buggy SIMH TAP images come from, that should be fixed.</div><div><br></div><div>
Larry Baker<br>US Geological Survey<br>650-329-5608<br><a href="mailto:baker@usgs.gov">baker@usgs.gov</a><br><br><br>
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