Sender: eric@ruckus.brouhaha.com From: Eric Smith Newsgroups: alt.folklore.computers Subject: DECtape and LINCtape (was Re: Smallest Storage Capacity Hard Disk?) References: <9t5ocv$qcl$7@bob.news.rcn.net> <9t5qj5$2ss$1@shell.golden.net> <9t5tb6$i36$1@bob.news.rcn.net> <9t7nht$9df$1@shell.golden.net> Organization: Eric Conspiracy Secret Labs X-Eric-Conspiracy: There is no conspiracy. Date: 18 Nov 2001 15:16:48 -0800 Message-ID: Lines: 61 User-Agent: Gnus/5.0807 (Gnus v5.8.7) Emacs/20.7 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii NNTP-Posting-Host: ruckus.brouhaha.com X-Trace: 18 Nov 2001 15:18:13 -0800, ruckus.brouhaha.com Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!newsfeeds.belnet.be!news.belnet.be!newsfeed.stanford.edu!news.kjsl.com!news.spies.com!ruckus.brouhaha.com Xref: chonsp.franklin.ch alt.folklore.computers:94640 jrlatala@shell.golden.net writes: > I guess another way of answering the question is to find out if > -12s were shipped with DECtapes or were they all LINCtapes? DECtape and LINCtape were the same tape wound in the reverse direction and stored in differently colored canisters. The tape media itself was interchangeable. The transports were identical. I'm not sure if there was a type number for the original LINCtape transport, but the later DECtape & LINCtape transports were Type 555, TU55, and TU56. The formatting used on DECtape and LINCtape was different. LINCtape used 12-bit words on tape, with a four-bit mark pattern associated with each 12-bit word. It was designed for bidirectional seek, but only to be read and written in the forward direction. DECtape used 18-bit words on tape, with a six-bit mark pattern associated with each 18-bit word. It was designed to support bidirectional read and write. Since DECtape was used on 12-, 16-, 18-, and 36-bit systems, the customary tape block size varied. Also, the tape could be formatted with blocks that contained an arbitrary number of 18-bit words, with a minimum of four. Larger blocks reduced the overhead and thus increased the total tape capacity, but decreased the effectiveness of the checksum. The LINC, LINC-8, and PDP-12 had integral LINCtape controls. In the case of the PDP-12 it was the TC12 LINCtape control, but with the TC12-F option was capable of reading and writing DECtape. The TC12-F required more software hand-holding to do this than a TC01 or TC08, but less than a TD8-E. It is also possible to use an external 552, TC01, or TC08 DECtape control on the PDP-12 and LINC-8. The PDP-5 and PDP-8 used 129 12-bit host words per block, although the software typically did not use the 129th word. Three 12-bit host words were packed into two 18-bit DECtape words, so the actual block size on tape was 86 DECtape words. The PDP-5 used a Type 552 DECtape control; the PDP-8 commonly used TC01, TC08, or TD8-E DECtape controls, although I have a PDP-8/I with a Type 552. The TD8-E is a single Omnibus module used with the PDP-8/E and PDP-8/A families; it is a "dumb" DECtape control and relies on software for most of the DECtape functions. The TD8-E is the only native DECtape control that is also capable of handling LINCtape. The PDP-4, PDP-7, -9, and -15 used 18-bit words natively. The PDP-6 and PDP-10 used 36-bit host words, which were recorded on DECtape as pairs of 18-bit words. The PDP-6 and PDP-10 normally used Type 550 and TD10 DECtape control, respectively. Some models of the KL10 processor had a DECtape transport as the console boot device, but that was interfaced to the front-end PDP-11/40 via a TC11 DECtape control, and was not directly available as a PDP-10 peripheral. The PDP-11 used 16-bit host words. These were recorded as 18-bit DECtape words, wasting two bits. The TC11 DECtape control made the extra two bits available in programmed I/O mode only, not in the normal sequence break mode (DEC-speak for DMA). This feature was provided for interchange with other DEC machines. Eric ###### From: jmfbahciv@aol.com Newsgroups: alt.folklore.computers Subject: Re: DECtape and LINCtape (was Re: Smallest Storage Capacity Hard Disk?) Date: Mon, 19 Nov 01 11:25:24 GMT Organization: UltraNet Communications, Inc. Lines: 39 Message-ID: <9tb17h$6rj$1@bob.news.rcn.net> References: <9t5ocv$qcl$7@bob.news.rcn.net> <9t5qj5$2ss$1@shell.golden.net> <9t5tb6$i36$1@bob.news.rcn.net> <9t7nht$9df$1@shell.golden.net> X-Trace: UmFuZG9tSVaWVRQqbWAcz+B9cU3A4SjSvGiwbmUJzlOjsxGeL6NGM+uJ+3NozhjP X-Complaints-To: abuse@rcn.com NNTP-Posting-Date: 19 Nov 2001 13:25:05 GMT X-Newsreader: News Xpress Version 1.0 Beta #4 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!news.maxwell.syr.edu!feed2.news.rcn.net!feed1.news.rcn.net!rcn!207-172-102-28 Xref: chonsp.franklin.ch alt.folklore.computers:94605 In article , Eric Smith wrote: Nice writeup. :-) >jrlatala@shell.golden.net writes: >> I guess another way of answering the question is to find out if >> -12s were shipped with DECtapes or were they all LINCtapes? > >DECtape and LINCtape were the same tape wound in the reverse direction >and stored in differently colored canisters. I'm having trouble with this. The leetle grey cells are just not sparking. Are you saying that a -12 had the DECtape mounted on the left hand reel? I'm assuming that the letters on the DECtape still had to be visible. >The PDP-6 and PDP-10 used 36-bit host words, which were recorded on >DECtape as pairs of 18-bit words. The PDP-6 and PDP-10 normally used >Type 550 and TD10 DECtape control, respectively. Some models of the >KL10 processor had a DECtape transport as the console boot device, but >that was interfaced to the front-end PDP-11/40 via a TC11 DECtape >control, and was not directly available as a PDP-10 peripheral. Small addition here. When a customer was convinced to upgrade from his KI to a KL, there was no way in hell that he would give up his TU56 so most of them were moved to the KL. Thus, there were DECtape drives on the -11 and there could be PDP-10 style DECtape drives on the -10 side, too. There were a few times when somebody would mount a tape on the -11 and couldn't figure out why the -10's DECtape wouldn't work...and visa versa. /BAH Subtract a hundred and four for e-mail. ###### From: djg@pdp8.net (David Gesswein) Newsgroups: alt.folklore.computers Subject: Re: DECtape and LINCtape (was Re: Smallest Storage Capacity Hard Disk?) Date: 18 Nov 2001 23:29:08 GMT Organization: www.pdp8.net Lines: 14 Message-ID: <9t9g84$7sm$1@slb6.atl.mindspring.net> References: <9t5tb6$i36$1@bob.news.rcn.net> <9t7nht$9df$1@shell.golden.net> NNTP-Posting-Host: 42.95.66.5e X-Newsreader: trn 4.0-test76 (Apr 2, 2001) Originator: djg@pdp8.net (David Gesswein) Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newscore.univie.ac.at!howland.erols.net!ix.netcom.com!news.mindspring.net!not-for-mail Xref: chonsp.franklin.ch alt.folklore.computers:94630 In article , Eric Smith wrote: > >The >TD8-E is the only native DECtape control that is also capable of handling >LINCtape. > Do you know of any existing software around to do this? I have made my TD8E dump 8/9/10/15 tapes but was having trouble decoding the mark track to dump the LINCtapes. David Gesswein http://www.pdp8.net/ -- Run an old computer with blinkenlights Have any PDP-8 stuff you're willing to part with? ###### From: jmfbahciv@aol.com Newsgroups: alt.folklore.computers Subject: Re: DECtape and LINCtape (was Re: Smallest Storage Capacity Hard Disk?) Date: Tue, 20 Nov 01 11:37:26 GMT Organization: UltraNet Communications, Inc. Lines: 42 Message-ID: <9tdmab$e26$6@bob.news.rcn.net> References: <9t5ocv$qcl$7@bob.news.rcn.net> <9t5qj5$2ss$1@shell.golden.net> <9t5tb6$i36$1@bob.news.rcn.net> <9t7nht$9df$1@shell.golden.net> <9tb17h$6rj$1@bob.news.rcn.net> X-Trace: UmFuZG9tSVbierT+N9gQBwIm18hpmRjQ904vDfkyp3W7uStxP07wNswirpUM2fB1 X-Complaints-To: abuse@rcn.com NNTP-Posting-Date: 20 Nov 2001 13:37:15 GMT X-Newsreader: News Xpress Version 1.0 Beta #4 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!newsfeeds.belnet.be!news.belnet.be!newsfeed.online.be!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!feed2.news.rcn.net!feed1.news.rcn.net!rcn!207-172-245-38 Xref: chonsp.franklin.ch alt.folklore.computers:94684 In article , Eric Smith wrote: >jmfbahciv@aol.com writes: >> I'm having trouble with this. The leetle grey cells are just not >> sparking. Are you saying that a -12 had the DECtape mounted on >> the left hand reel? I'm assuming that the letters on the DECtape >> still had to be visible. > >As to the last question, yet. > >On a PDP-12, a LINCtape would normally be mounted on the right hub, >with a takeup reel on the left. If the TC12-F option is installed, >DECtapes may be used by mounting them on the left hub with a takeup >reel on the right. WEll, the grey cells were absent yesterday. I dreamed last night how I used to mount DECtapes. I had it bassackwards when I posted yesterday. Bah! > >You could convert a LINCtape to DECtape or vice versa by using the >transport to wind it onto the "takeup reel", which became the new >tape reel. We had to do that if the hardware got confused. IIRC, (this is a big IF), there was a knack to setting the buttons just so so that a rewind would continue without an operator's finger attached to the rewind button. But I can't remember if both button flavors could do that. There were two types of rocker switches; one kind looked square and clicked and the other kind had oblong oval switches. I think the latter could be manipulated so a DECtape could be started to rewind and then left. /BAH >Then you have to reformat it, of course, since LINCtape >and DECtape use entirely different mark track formats. Subtract a hundred and four for e-mail. ###### Sender: eric@ruckus.brouhaha.com From: Eric Smith Newsgroups: alt.folklore.computers Subject: Re: DECtape and LINCtape (was Re: Smallest Storage Capacity Hard Disk?) References: <9t5ocv$qcl$7@bob.news.rcn.net> <9t5qj5$2ss$1@shell.golden.net> <9t5tb6$i36$1@bob.news.rcn.net> <9t7nht$9df$1@shell.golden.net> <9tb17h$6rj$1@bob.news.rcn.net> Organization: Eric Conspiracy Secret Labs X-Eric-Conspiracy: There is no conspiracy. Date: 19 Nov 2001 12:37:20 -0800 Message-ID: Lines: 17 User-Agent: Gnus/5.0807 (Gnus v5.8.7) Emacs/20.7 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii NNTP-Posting-Host: ruckus.brouhaha.com X-Trace: 19 Nov 2001 12:38:55 -0800, ruckus.brouhaha.com Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newscore.univie.ac.at!newsmi-eu.news.garr.it!newsmi-us.news.garr.it!NewsITBone-GARR!newsfeed.stanford.edu!news.kjsl.com!news.spies.com!ruckus.brouhaha.com Xref: chonsp.franklin.ch alt.folklore.computers:94717 jmfbahciv@aol.com writes: > I'm having trouble with this. The leetle grey cells are just not > sparking. Are you saying that a -12 had the DECtape mounted on > the left hand reel? I'm assuming that the letters on the DECtape > still had to be visible. As to the last question, yet. On a PDP-12, a LINCtape would normally be mounted on the right hub, with a takeup reel on the left. If the TC12-F option is installed, DECtapes may be used by mounting them on the left hub with a takeup reel on the right. You could convert a LINCtape to DECtape or vice versa by using the transport to wind it onto the "takeup reel", which became the new tape reel. Then you have to reformat it, of course, since LINCtape and DECtape use entirely different mark track formats. ###### From: aek@spies.com (Al Kossow) Newsgroups: alt.folklore.computers Subject: Re: DECtape and LINCtape (was Re: Smallest Storage Capacity Hard Disk?) Date: Tue, 20 Nov 2001 09:47:54 -0800 Organization: Apple Computer, Inc. Lines: 12 Message-ID: References: <9t5ocv$qcl$7@bob.news.rcn.net> <9t5qj5$2ss$1@shell.golden.net> <9t5tb6$i36$1@bob.news.rcn.net> <9t7nht$9df$1@shell.golden.net> <9tb17h$6rj$1@bob.news.rcn.net> <9tdmab$e26$6@bob.news.rcn.net> NNTP-Posting-Host: il0502a-dhcp193.apple.com X-Trace: news.apple.com 1006278473 10729 17.205.24.193 (20 Nov 2001 17:47:53 GMT) X-Complaints-To: usenet@news.apple.com NNTP-Posting-Date: 20 Nov 2001 17:47:53 GMT Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newsfeed.nextra.ch!news.nextra.ch!nextra.at!newsfeed4.cidera.com!newsfeed1.cidera.com!Cidera!dca6-feed2.news.digex.net!intermedia!feed2.news.rcn.net!rcn!cpk-news-hub1.bbnplanet.com!paloalto-snf1.gtei.net!news.gtei.net!forum.apple.com!news.apple.com!il0502a-dhcp193.apple.com!user Xref: chonsp.franklin.ch alt.folklore.computers:94714 In article <9tdmab$e26$6@bob.news.rcn.net>, jmfbahciv@aol.com wrote: > WEll, the grey cells were absent yesterday. I dreamed last night > how I used to mount DECtapes. Single-finger technique? (spin your index finger over the left hub, picking up the tape, and spooling it onto the right one in a single motion..) I was never very good at doing it that way, but the people who spent a lot of time at the TSS/8 console had it down to an art. ###### From: David Powell Newsgroups: alt.folklore.computers Subject: Re: DECtape and LINCtape (was Re: Smallest Storage Capacity Hard Disk?) Date: Tue, 20 Nov 2001 21:19:01 +0000 Reply-To: ddotpowell@netscapeonline.co.uk Message-ID: <25ilvtk7ppoic6gqani2meudnmcbs0jt7g@4ax.com> References: <9t5ocv$qcl$7@bob.news.rcn.net> <9t5qj5$2ss$1@shell.golden.net> <9t5tb6$i36$1@bob.news.rcn.net> <9t7nht$9df$1@shell.golden.net> <9tb17h$6rj$1@bob.news.rcn.net> X-Newsreader: Forte Agent 1.8/32.548 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit NNTP-Posting-Host: ch8as01-65-156-70.cw-visp.com X-Trace: 20 Nov 2001 20:22:28 GMT, ch8as01-65-156-70.cw-visp.com Lines: 34 X-Report: Report abuse to abuse@netscapeonline.co.uk Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newsfeed.nextra.ch!news.nextra.ch!nextra.at!newsfeed4.cidera.com!newsfeed1.cidera.com!Cidera!diablo.theplanet.net!diablo.netcom.net.uk!netcom.net.uk!newsfeed.icl.net!iclnet!plato.netscapeonline.co.uk!ch8as01-65-156-70.cw-visp.com Xref: chonsp.franklin.ch alt.folklore.computers:94745 In article , Eric Smith in alt.folklore.computers wrote: > >On a PDP-12, a LINCtape would normally be mounted on the right hub, >with a takeup reel on the left. If the TC12-F option is installed, >DECtapes may be used by mounting them on the left hub with a takeup >reel on the right. If you look at the circular label on the canister, you see 3 horizontal green or blue bars, and a "walking stick" shaped bar underneath. If you take that as a stylized illustration of a tape, then, for the DECtape, the tape goes to the right, with "TAPE" in reversed colour, and for the LINCtape goes to the left, with "LINK" in reversed colour. With the tape in the canister, face down so that the tape identification is visible through the base of the canister, then the LINC / DEC tape matches the label > >You could convert a LINCtape to DECtape or vice versa by using the >transport to wind it onto the "takeup reel", which became the new >tape reel. Then you have to reformat it, of course, since LINCtape >and DECtape use entirely different mark track formats. ... and the well worn and stretched directory area of the tape is now at the end of tape, and (often) virgin tape is used for the new directory. Sure beats turning the tape end to end if you only have one sort. Regards, David P. ###### From: jmfbahciv@aol.com Newsgroups: alt.folklore.computers Subject: Re: DECtape and LINCtape (was Re: Smallest Storage Capacity Hard Disk?) Date: Wed, 21 Nov 01 11:45:16 GMT Organization: UltraNet Communications, Inc. Lines: 24 Message-ID: <9tgb5d$18b$7@bob.news.rcn.net> References: <9t5ocv$qcl$7@bob.news.rcn.net> <9t5qj5$2ss$1@shell.golden.net> <9t5tb6$i36$1@bob.news.rcn.net> <9t7nht$9df$1@shell.golden.net> <9tb17h$6rj$1@bob.news.rcn.net> <9tdmab$e26$6@bob.news.rcn.net> X-Trace: UmFuZG9tSVbJPV5fmEmMVHJoDWuZ4jco4LsFAv122nTv/T4THi2feBPd/7VXfBJg X-Complaints-To: abuse@rcn.com NNTP-Posting-Date: 21 Nov 2001 13:45:17 GMT X-Newsreader: News Xpress Version 1.0 Beta #4 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!news.bme.hu!andromeda.datanet.hu!newsfeed.gamma.ru!Gamma.RU!feed2.news.rcn.net!feed1.news.rcn.net!rcn!209-122-236-77 Xref: chonsp.franklin.ch alt.folklore.computers:94773 In article , aek@spies.com (Al Kossow) wrote: >In article <9tdmab$e26$6@bob.news.rcn.net>, jmfbahciv@aol.com wrote: > >> WEll, the grey cells were absent yesterday. I dreamed last night >> how I used to mount DECtapes. > >Single-finger technique? That's just a tease. To do it right, you have to use the two-handed technique. > >(spin your index finger over the left hub, picking up the tape, > and spooling it onto the right one in a single motion..) > >I was never very good at doing it that way, but the people who >spent a lot of time at the TSS/8 console had it down to an art. You also have to include pushing the toggles and then setting it on-line. /BAH Subtract a hundred and four for e-mail.