<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Michael,</div><div><br></div><div>See the following web pages for some information on ANSI labelled tapes:</div><div><br></div><a href="http://h71000.www7.hp.com/doc/731final/4506/4506pro_002.html">http://h71000.www7.hp.com/doc/731final/4506/4506pro_002.html</a><div><br></div><div>http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi?coll=linux&db=bks&fname=/SGI_EndUser/TMF_UG/ch02.html</div><div><br></div><div>Here's what a typical tape looks like, where TM is a tape mark, HDRn/EOF1/EOVn are tape labels, and DATA is the data portion of a file:</div><div><br></div><div>VOL1 HDR1 HDR2 TM DATA TM EOF1 EOF2 TM ... HDR1 HDR2 TM DATA TM EOF1 EOF2 TM TM</div><div><br></div><div>ANSI tapes have a VOL1 volume label at the beginning of the tape. Following that, for each file on the tape, are HDRn header labels, the data, and EOFn end-of-file/EOVn end-of-volume labels. EOVn labels are only written when a tape volume spans multiple reels. You will not have that case (I assume). The EOFn/EOVn labels are identical to the corresponding HDRn labels, with fields filled in that are not yet known when the HDRn labels are written, such as the number of records and blocks in the file. HDR1 labels have the file name. HDR2 labels have the record format. HDR3-HDR9 labels are reserved for system use. VMS uses HDR3 labels for RMS metadata. Those were optional (you can MOUNT an ANSI tape on VMS with the /NOHDR3 option), and are not understood or necessary for reading ANSI labelled tapes on RSX-11. I assume RSTS is the same.</div><div><br></div><div><div>Double tape marks mark the end of the volume where the next HDR1 labels would be. Note: a file can be empty, that is, can contain no data. Thus, it is perfectly legal for an ANSI labelled tape to have consecutive tape marks where the DATA would be:</div><div><br></div><div><div>VOL1 HDR1 HDR2 TM TM EOF1 EOF2 TM TM</div><div><br></div></div><div>In this case, the first set of double tape marks does not indicate the end of the volume. A lot of people think double tape marks ends a tape, but that is not always the case.</div><div><br></div></div><div>You will have to find out how RSTS uses ANSI labelled tapes. On VMS and RSX-11, text files were written in ANSI "D" format, the format for variable-length records. Much like FTP "TEXT" mode, CR and LF are stripped, or, on Unix, the terminating NUL is removed. The remaining text is prefixed with a 4 byte record control word (RCW), which is the count of the number of characters in the record, including the RCW. (Thus, a null record is written as an RCW=4 with no other characters following the RCW.) Records are spliced together without any padding, as for example, to 16-bit or 32-bit boundaries. The blocks, however, can be padded to match the requirements of the hardware. (PDP-11's required even block lengths.) ASCII circumflex characters are used for the padding character. The other ANSI formats are "F", for fixed-length records, and "S", for spanned records (records that can span multiple blocks).</div><div><br></div><div>I have Fortran routines that I have used to write ANSI labelled tapes from a data acquisition system. You can steal the code, if you like. However, I used fixed-length records, so I used ANSI "F" format, not ANSI "D" format. I might have some code somewhere that can pack and unpack ANSI "D" format. I'll have a look.</div><div><br></div><div>Larry Baker</div><div><div apple-content-edited="true"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div><div><div><div><div><div><div><div><div>US Geological Survey</div><div>650-329-5608</div><div>baker@usgs.gov</div></div></div></div></div></div></div></div></div></div></div> </div><br><div><div>On Apr 29, 2010, at 5:36 PM, Michael Richter wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">Larry,<div><br></div><div>RSTS/E v9.6 is the guest operating system. Using another SIMH simulation to do this isn't really suitable. (To begin with I haven't yet solved the problem of getting the OpenVMS CD, but that's a different issue.) I have loose files--many of them--I want to get into the PDP-11without hand-typing thousands of lines of MACRO-11 source. Using a SIMH VAX to do this just moves the typing problem around. It would be nice if I could manually construct a tape image on the host system instead of the simulated ones.<br> <br></div><div>DECnetting it would be a bit of overkill, but I'll investigate if I can get that working.</div><div><br></div><div>Another possibility would be ... is the specification for ANSI-labelled tapes lying around somewhere? I could hack together a tar-like program to build those from outside of the DEC world if the spec is available somewhere.</div> <div><br><div class="gmail_quote">On 30 April 2010 01:58, Larry Baker <span dir="ltr"><<a href="mailto:baker@usgs.gov">baker@usgs.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"> <div style="word-wrap:break-word"><div>Michael,</div><div><br></div>Which PDP-11 O/S? Will it have DECnet access to another system (e.g., a SIMH VAX or linux-decnet)?<div><br></div><div>OpenVMS system can create and mount a Files-11 Level 1 disk volume, which can be read/written by RSX-11M/M-Plus and IAS. You could create a virtual Files-11 Level 1 volume with a SIMH VAX and then read it on a SIMH PDP-11. The same SIMH VAX can create a SIMH virtual ANSI-labelled tape, which can be read/written by those O/S's, and RSTS, I assume (I have never used RSTS). RT-11 disk volumes and DOS-11 tape volumes can be created with the OpenVMS EXCHANGE utility. Any of these can be to virtual devices that can be cross-mounted on various SIMH machines, as long as the O/S supports the volume format.</div> <div><br></div><div>Of course, any systems that are DECnet'ed together can exchange files. I use linux-decnet on a CentOS (Red Hat) file server to store OpenVMS Backup save sets that are created using remote file access (FAL) directly from the Backup command. linux-decnet may not be available for very much longer -- the people that supported the DECnet code in the Linux kernel can no longer keep up with the latest versions of the kernel.<div> <br><div> <span style="border-collapse:separate;color:rgb(0, 0, 0);font-family:'Helvetica Neue';font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><div style="word-wrap:break-word"> <div><div><div><div><div><div><div><div><div><div>Larry Baker</div><div>US Geological Survey</div><div>650-329-5608</div><div><a href="mailto:baker@usgs.gov" target="_blank">baker@usgs.gov</a></div></div></div></div></div> </div></div></div></div></div></div></span> </div><br><div><div>On Apr 29, 2010, at 9:00 AM, <a href="mailto:simh-request@trailing-edge.com" target="_blank">simh-request@trailing-edge.com</a> wrote:</div><br><blockquote type="cite"> <span style="border-collapse:separate;color:rgb(0, 0, 0);font-family:'Helvetica Neue';font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;text-align:auto;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:monospace">Message: 2<br> Date: Thu, 29 Apr 2010 14:54:50 +0800<br>From: Michael Richter <<a href="mailto:ttmrichter@gmail.com" target="_blank">ttmrichter@gmail.com</a>><br>Subject: [Simh] Making tape/disk images<br>To: simh <<a href="mailto:simh@trailing-edge.com" target="_blank">simh@trailing-edge.com</a>><br> Message-ID:<br><span style="white-space:pre"> </span><<a href="mailto:o2mee970b291004282354xbfdea62dwe8e2b8389f27a5b3@mail.gmail.com" target="_blank">o2mee970b291004282354xbfdea62dwe8e2b8389f27a5b3@mail.gmail.com</a>><br> Content-Type: text/plain; charset="utf-8"<div class="im"><br><br>Is there an easy way to take a bunch of files and turn them into either a<br>tape image or a disk image suited for attaching to a PDP-11 under SIMH?<br> </div></span></span></blockquote></div><br></div></div></div></blockquote></div><br><br clear="all"><br>-- <br>"Perhaps people don't believe this, but throughout all of the discussions of entering China our focus has really been what's best for the Chinese people. It's not been about our revenue or profit or whatnot."<br> --Sergey Brin, demonstrating the emptiness of the "don't be evil" mantra.<br> </div></blockquote></div><br></div></body></html>