<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">First, what are you using for bands? (size and manufacturer).</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">With regard to the tape itself, given that these are old tapes, assume you will get one shot in the transport. So I >>highly<< recommend using the old 1985 copytape utility <span class="Asgive ng" style="border-style:none;background:none">from the</span> USENET (pdf of its man <span class="Asgive ng" style="border-style:none;background:none">page of</span> the command and the format it <span class="Q6ibn ng" style="border-style:none;background:none">writes</span> attached), and creating a tape image you can decode without needing to touch either the tape or the transport. If you don't have it, send me an email off-list, and I'll be happy to provide it to you.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span class="Q6ibn ng" style="border-style:none;background:none">copytape</span> will attempt to read 262144 (256K) bytes at a time. On a QIC drive, which has fixed-size (512-byte) records, that <span class="Q6ibn ng" style="border-style:none;background:none">will equate</span> to 512 <span class="Asgive ng" style="border-style:none;background:none">blocks (on</span> a 9-<span class="Asgive ng" style="border-style:none;background:none">track,</span> which used variable-sized records, each 256k read, will return as many bytes as were written on that tape record, which can<span class="Asgive ng" style="border-style:none;background:none"> be a small integer to no more than 65536</span> (64K bytes). Copytape will read tape marks. Tape "files" are delineated by tape marks. On drivers that were written properly, the last "tape file" will have a second tape mark [<i>i.e.</i>, two in a row] to delineate EOT. Note that many of the QIC drivers do not do that (and neither did Ken's original 9-track tape driver for Fifth Edition and IIRC Sixth, but by then a number of us had rewritten to 9-track drivers <span class="Asgive ng" style="border-style:none;background:none">to be </span> much smarter, but I digress)<br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Once you have a copy of the tape in "copytape" format, you can decode it much more easily.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style=""><span style="font-family:arial,helvetica,sans-serif">A</span><font face="arial, sans-serif">s for the format itself, it depends on which Computer Vision system wrote it. Their early systems were based on DG Novas and ran RDOS (similar to DEC's RT11). From the late 70s until the mid 1980s, they replaced RDOS with their own OS called CGOS (<span style="color:rgb(10,10,10)">Computervision Graphics Operating System), and by the late 80's, early 90's, they had ported their CADDS system to run on UNIX and started shipping it on Suns. Finally, <span class="Asgive ng" style="border-style:none;background:none">they got bought by Prime, and then</span> moved it again to PRIMOS.</span></font></div><div class="gmail_default" style=""><font face="arial, sans-serif"><span style="color:rgb(10,10,10)"><br></span></font></div><div class="gmail_default" style=""><font face="arial, sans-serif"><span style="color:rgb(10,10,10)">Given that this is a QIC tape, the time frame says either late CGOS or SunOS, although Prime might have supported QIC; I never saw anything but 9-track on their systems.</span></font></div><div class="gmail_default" style=""><font face="arial, sans-serif"><span style="color:rgb(10,10,10)"><br></span></font></div><div class="gmail_default" style=""><font face="arial, sans-serif"><span style="color:rgb(10,10,10)">So ... if it was written on an early CV system, it is likely to be in what DG called MTIO format or possibly in the DG backup format. </span></font>Data General\u2019s RDOS natively used raw, streaming sequential blocks without a complex, metadata-heavy file system structure, such as ANSI labeled tapes (DEC often used a superset - embrace and extend - ANSI tape format). I don't know what CGOS used, but I suspect it was similar to the DG style. If it was written on a Sun or other UNIX box, it is likely to be TAR (hopefully) or CPIO. If the latter, there is a slew of different CPIO on tape formats - this is historical because<span class="Asgive ng" style="border-style:none;background:none"> it</span> was created for PDP-11s and was a binary format.<font face="arial, sans-serif"><span style="color:rgb(10,10,10)"> It could also be one of the many UNIX backup formats, so you will need to do a little examination to determine which one. Modern versions of the original V7 Unix file(1) >>might<< be able to identify the format. Finally, l</span></font><span style="font-family:arial,sans-serif;color:rgb(10,10,10)">ike DG, Prime opted not to use DEC-style (pseudo-ANSI) labeled file structures natively. Instead, they also created their own proprietary, streaming binary format deeply tied to PRIMOS\u2019s unique disk architecture and </span>character encodings. I've never seen documentation on this format.</div><div class="gmail_default" style=""><font face="arial, sans-serif"><span style="color:rgb(10,10,10)"> </span></font></div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Thu, May 14, 2026 at 9:44\u202fAM Alan Perry via rescue <<a href="mailto:rescue@sunhelp.org">rescue@sunhelp.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">I seem to have found a working combination of drive and replacement's bands to be able to get images of the dozens of Computervision install tapes that I have.<br>
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They are QIC-24 from the late 80s and aren\u2019t in the \u201ccollection of tar files\u201d format that I usually use mt fsf and dd to read. Each tape starts with a file with a \u201ctapedir\u201d record with permission and other stuff, followed by a bunch of records that look like a number followed by a topic or title. What am I looking at and what do I use to get the info off of the tape?<br>
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alan<br>
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