<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<div class="moz-cite-prefix">Good information, but this thread is
about DECtape, not 9-Track magtapes...<br>
<br>
The format looks about right for 9-track DOS-11 magtapes; I
remember writing code to extract files from them on the -10. <br>
<br>
It's not right (or at least, not complete) for the
block-addressable DECtapes.<br>
<br>
I don't think DOS-11 would have been documented in any of the
references cited.<br>
<br>
There's now a SIMH repo on github; your utility could go into the
tools section.<br>
<br>
<pre class="moz-signature" cols="72">This communication may not represent my employer's views,
if any, on the matters discussed. </pre>
On 28-Mar-13 14:09, Larry Baker wrote:<br>
</div>
<blockquote cite="mid:AFAC523A-E0FD-432D-802F-0224D8A210C1@usgs.gov"
type="cite">
<div><span class="Apple-style-span" style="border-collapse:
separate; color: rgb(0, 0, 0); font-family: 'Helvetica Neue';
font-style: normal; font-variant: normal; font-weight: normal;
letter-spacing: normal; line-height: normal; orphans: 2;
text-align: -webkit-auto; text-indent: 0px; text-transform:
none; white-space: normal; widows: 2; word-spacing: 0px;
-webkit-border-horizontal-spacing: 0px;
-webkit-border-vertical-spacing: 0px;
-webkit-text-decorations-in-effect: none;
-webkit-text-size-adjust: auto; -webkit-text-stroke-width:
0px; font-size: medium; ">On 28 Mar 2013, at 5:24 AM, <<a
moz-do-not-send="true"
href="mailto:simh-request@trailing-edge.com">simh-request@trailing-edge.com</a>>
<<a moz-do-not-send="true"
href="mailto:simh-request@trailing-edge.com">simh-request@trailing-edge.com</a>>
wrote:</span></div>
<div><br class="Apple-interchange-newline">
<blockquote type="cite"><span class="Apple-style-span"
style="border-collapse: separate; font-family: 'Helvetica
Neue'; font-style: normal; font-variant: normal;
font-weight: normal; letter-spacing: normal; line-height:
normal; orphans: 2; text-align: -webkit-auto; text-indent:
0px; text-transform: none; white-space: normal; widows: 2;
word-spacing: 0px; -webkit-border-horizontal-spacing: 0px;
-webkit-border-vertical-spacing: 0px;
-webkit-text-decorations-in-effect: none;
-webkit-text-size-adjust: auto; -webkit-text-stroke-width:
0px; font-size: medium; "><span class="Apple-style-span"
style="font-family: monospace; ">Google 'AA-JS16A-TC' for
some Files-11 format information; I'd<span
class="Apple-converted-space"> </span><br>
have to think a bit on the DOS-11 format.</span></span></blockquote>
</div>
<div><br>
</div>
RSX/VMS Files-11 tapes are ANSI labeled tapes. I know OpenVMS
also used HDR3/4 labels for RMS information. There was a MOUNT
option to suppress writing those labels.
<div><br>
</div>
<div>I wrote an RSX/VMS program that will scan an unknown tape
and decode it for you. (If anyone wants it, let me know where I
should upload it.) The DOS format decoder looks for a 14 byte
(physical) record at the start of the file. It is decoded by
the following code:</div>
<div><br>
</div>
<div>
<div>C</div>
<div>C... DEC DOS labels</div>
<div>C</div>
<div> Call R50ASC ( 6, buffer( 1), ascbuf( 1) )</div>
<div> Call R50ASC ( 3, buffer(13), ascbuf( 7) )</div>
<div> ascbuf(10) = '.'</div>
<div> Call R50ASC ( 3, buffer( 5), ascbuf(11) )</div>
<div> ltemp(1) = buffer(7)</div>
<div> ltemp(2) = 0</div>
<div> mem = itemp</div>
<div> ltemp(1) = buffer(8)</div>
<div> grp = itemp</div>
<div> ltemp(1) = buffer(11)</div>
<div> ltemp(2) = buffer(12)</div>
<div> jday = MOD(itemp,1000)</div>
<div> year = itemp/1000 + 70</div>
<div> Call JDCONV ( jday, mon, day, year )</div>
<div> ltemp(1) = buffer( 9)</div>
<div> ltemp(2) = buffer(10)</div>
<div> Write (STDOUT,619) ifile, grp, mem, ascbuf, day,
month(mon),</div>
<div> 1 year, itemp</div>
<div> 619 Format (//' File ', I4, ':', T34, '"', '[', O3.3,
',', O3.3, ']',</div>
<div> 1 13A1, 2X, I2, '-', A, '-', I2.2, ' <',
O3.3, '>', '"')</div>
</div>
<div><br>
</div>
<div>The DOS label contents are:</div>
<div><br>
</div>
<div>Words 1-2 RAD50 characters 1-6 of the file name part (before
the implied period)</div>
<div>Word 3 RAD50 characters 1-3 of the file type (after the
implied period)</div>
<div>Word 4 Octal File owner's User Identification Code (group
code in high-order byte, member code in low-order byte)</div>
<div>Word 5 Binary File creation date ( 1000 * ( year - 1970 ) +
Julian day )</div>
<div>Word 6 Octal File protection (low-order to high-order RWED
bits: read, write, extend, delete; grouped low-order to
high-order for system, owner, group, world)</div>
<div>Word 7 RAD50 characters 7-9 of the file name part (before the
implied period)</div>
<div><br>
</div>
<div>The references I used to write the program (back in the
1980's) are below. Which reference had the DOS label format I
don't remember (if any of them did).</div>
<div><br>
</div>
<div>
<div>6 References</div>
<div><br>
</div>
<div>[1] American National Standards Institute, 1978, Magnetic
Tape Labels</div>
<div> and File Structure for Information Interchange (ANSI
X3.27-1978).</div>
<div><br>
</div>
<div>[2] Digital Equipment Corp., 1985, RSX-11M/M-Plus MCR
Operations</div>
<div> Manual (Order no. AA-FD10A-TC).</div>
<div><br>
</div>
<div>[3] Digital Equipment Corp., 1985, RSX-11M-Plus
Command Language</div>
<div> Manual (Order no. AA-FD04A-TC).</div>
<div><br>
</div>
<div>[4] Digital Equipment Corp., 1985, RSX-11M/M-Plus and
Micro/RSX I/O</div>
<div> Operations Reference Manual (Order no. AA-FD14A-TC).</div>
<div><br>
</div>
<div>[5] Digital Equipment Corp., 1985, RSX-11M/M-Plus
I/O Drivers</div>
<div> Reference Manual (Order no. AA-FD09A-TC).</div>
<div><br>
</div>
<div>[6] Digital Equipment Corp., 1984, VAX/VMS Command
Definition Utility</div>
<div> Reference Manual (Order no. AA-Z408A-TE).</div>
<div><br>
</div>
<div>[7] Digital Equipment Corp., 1986, VAX/VMS DCL Dictionary
(Order no.</div>
<div> AA-Z200C-TE).</div>
<div><br>
</div>
<div>[8] Digital Equipment Corp., 1984, VAX/VMS Mount Utility
Reference</div>
<div> Manual (Order no. AA-Z424C-TE).</div>
<div><br>
</div>
<div>[9] Digital Equipment Corp., 1986, Guide to VAX/VMS Disk
and Magnetic</div>
<div> Tape Operations (Order no. AI-Y506B-TE).</div>
<div><br>
</div>
<div>[10] Digital Equipment Corp., 1986, VAX/VMS I/O User's
Reference</div>
<div> Manual: Part I (Order no. AA-Z600C-TE).</div>
<div><br>
</div>
<div>[11] International Business Machines Corp., 1978, OS/VS
Tape Labels</div>
<div> (Order No. GC26-3795-1).</div>
<div><br>
</div>
<div>Larry Baker<br>
US Geological Survey<br>
650-329-5608<br>
<a moz-do-not-send="true" href="mailto:baker@usgs.gov">baker@usgs.gov</a><br>
</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
Simh mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Simh@trailing-edge.com">Simh@trailing-edge.com</a>
<a class="moz-txt-link-freetext" href="http://mailman.trailing-edge.com/mailman/listinfo/simh">http://mailman.trailing-edge.com/mailman/listinfo/simh</a></pre>
</blockquote>
<br>
</body>
</html>