Article 2043 of alt.sys.pdp10: Sender: eric@ruckus.brouhaha.com From: Eric Smith Newsgroups: alt.sys.pdp10 Subject: Massbus (was Re: I have a KS10 now! ^_^) References: <8vtt5l$gd1$6@bob.news.rcn.net> X-Disclaimer: Everything I write is false. Organization: Eric Conspiracy Secret Labs X-Eric-Conspiracy: There is no conspiracy. Date: 28 Nov 2000 11:31:38 -0800 Message-ID: Lines: 38 X-Newsreader: Gnus v5.7/Emacs 20.7 NNTP-Posting-Host: ruckus.brouhaha.com X-Trace: 28 Nov 2000 11:32:55 -0800, ruckus.brouhaha.com Path: nntp1.ba.best.com!news1.best.com!nntp.primenet.com!nntp.gblx.net!enews.sgi.com!news.sgi.com!news.spies.com!ruckus.brouhaha.com Xref: nntp1.ba.best.com alt.sys.pdp10:2043 jmfbahciv@aol.com writes: > You've got -11s and no Massbus stuff? Why do you need a Massbus > for a KS (or have I really got my hardware jargon brain farted all > over the place?). You're probably thinking of Unibus, which is the PDP-11 bus. Massbus was the host-independent disk/tape interface in common use on high-end DEC gear from 1973 (?) to the mid 1980s. It was later replaced by other interconnects such as CI, SDI, STI, DSSI, and SCSI. Massbus has an 18-bit data path, a 16-bit control/status path, and a bunch of handshaking and control signals. There are a total of 60 differential pairs to a Massbus. Internal Massbus cabling uses three 40-conductor flat cables with the ubiquitous 40-bit Berg sockets. External Massbus cabling uses twisted pairs, with connectors consisting of three of the Berg sockets in parallel in a connector shell. The data path and control/status path can be used simultaneously; once a data transfer is set up, the the host can use the control/status path to monitor the drive, seek on other drives, or prepare another drive for a data transfer. Note that although there is no electrical problem with putting disks and tapes on the same Massbus, in practice none of the host software supports it. So most systems have at least two Massbus channels. The KA10 and KI10 use an external RH10 Massbus channel. The KL10 can use either the RH10 or the internal RH20 Massbus channel. The KS10 uses a slightly modified form of the RH11 Massbus adapter as used on the PDP-11 Unibus. VAXen use the RH780 and RH750 Massbus adapters. Commonly used Massbus drives include the RP04, RP05, RP06, RP07, RM03, RM05, and RS04 disks, and the TE16, TU45, TU77, TU78, and TU79 tapes. Article 2053 of alt.sys.pdp10: From: wilson@dbit.com (John Wilson) Newsgroups: alt.sys.pdp10 Subject: Re: Massbus (was Re: I have a KS10 now! ^_^) Date: 28 Nov 2000 23:02:58 -0500 Organization: D Bit, Troy, NY Lines: 24 Message-ID: <901v5i$agv$1@dbit.dbit.com> References: <8vtt5l$gd1$6@bob.news.rcn.net> <6un1ejhb2u.fsf@chonsp.franklin.ch> NNTP-Posting-Host: dbit.dbit.com X-Original-NNTP-Posting-Host: dbit.dbit.com X-Trace: 28 Nov 2000 23:03:52 -0500, dbit.dbit.com XPident: wilson X-Original-NNTP-Posting-Host: 199.181.141.3 XPident: Unknown Path: nntp1.ba.best.com!news1.best.com!newsfeed.mathworks.com!news.mv.net!newspeer.phoen-x.net!news.wizvax.net!dbit.com!not-for-mail Xref: nntp1.ba.best.com alt.sys.pdp10:2053 In article <6un1ejhb2u.fsf@chonsp.franklin.ch>, Neil Franklin wrote: >Now you write that the KS10 switched to using them. Did they do >something to them to make them faster? Or did the KS10 take an disk >throughput speed hit for this? Yes and yes. The RH11C is jumpered as a "bus hog" with some ridiculous burst length, which is the only way it could keep up with the RM03 and RM80 (which are officially not supported on the RH11AB since there aren't enough 3341s to buffer a whole sector, or something like that). The "disk" RH11C has to be the only thing on the "disk" Unibus to pull this off. But it's still pretty weak, it would have been much cleaner if DEC had built an "RH2020" or whatever, i.e. an MBA which sits directly on the KS10 backplane bus, so it could have been faster, plus it wouldn't have had to get mired in the Unibus map ugliness. But obviously DEC didn't feel it was worth the trouble for a low-end system. So you get a pretty long chain for e.g. RM80 disk I/O on a KS: backplane bus => UBA => RH11C => RM adapter => SMD personality module => R80 Each step of the way probably burns another 50 watts, too ... John Wilson D Bit Article 2057 of alt.sys.pdp10: Path: nntp1.ba.best.com!news1.best.com!newsfeed.mathworks.com!europa.netcrusader.net!207.172.3.44!feed2.news.rcn.net!feed1.news.rcn.net!rcn!207-172-245-130 From: jmfbahciv@aol.com Newsgroups: alt.sys.pdp10 Subject: Re: I have a KS10 now! ^_^ Date: Wed, 29 Nov 00 11:17:17 GMT Organization: UltraNet Communications, Inc. Lines: 21 Message-ID: <902sck$514$3@bob.news.rcn.net> References: <8vtt5l$gd1$6@bob.news.rcn.net> <9012kq$1dd5$1@nntp1.ba.best.com> X-Trace: dcRoK02F9CwqAM2kIf+n5NUAtQvTCSlhMe53KYpOHaw= X-Complaints-To: abuse@rcn.com NNTP-Posting-Date: 29 Nov 2000 12:21:40 GMT X-Newsreader: News Xpress Version 1.0 Beta #4 Xref: nntp1.ba.best.com alt.sys.pdp10:2057 In article <9012kq$1dd5$1@nntp1.ba.best.com>, inwap@best.com (Joe Smith) wrote: >In article <8vtt5l$gd1$6@bob.news.rcn.net>, wrote: >>In article , >> Daniel Seagraves wrote: >>> >>>KS10 serial number 4469. I don't know if it's alive or dead yet. >>>I also got a TU45, and a spare formatter for it. >> >>What's a formatter for a TU45? > >In order to connect a TU45 tape drive to a Massbus cable, you have to have >a thing called a formatter; TM02 or TM03. Oh, _that_ thing. I don't think I ever heard the guys refer to it as a formatter. Thanks, Joe. /BAH Subtract a hundred and four for e-mail.