Re: What was a Terminal Concentration Device in DEC's products?
http://www.bitsavers.org/pdf/dec/qbus/EK-DHQ11-UG-002.pdf DHQ11 User Guide, EK-DHQ11-UG.002 The main application of the M3107 DHQ11 is for interactive terminal handling; it can also be used for data concentration and real-time processing. It has two programming modes, DHV11 and DHU11. The register sets in these modes are compatible with those of the DHV11 and DHU11 respectively. The preferred mode of operation is DHU11 mode. The main features of the DHQ11 are: • For transmission: DMA transfers; or for each line, program transfers to a 1 character transmit buffer in DHV11 mode, or to a 64-character transmit FIFO in DHU11 mode • For receive: a 256-entry FIFO buffer for received characters, dataset status changes, and diagnostic information The M3118 CXA16 and the M3119 CXA08 have the same programming interface as the M3107 DHQ11 The M3108 DSV11 can do DMA transfers in both directions, although it is a synchronous interface, not asynchronous. http://www.bitsavers.org/pdf/dec/qbus/EK-DSV11-TM-001_Jan87.pdf DSV11 Technical Manual, EK-DSV11-TM-001 Functional Description (Section 1.5). The DSV11 supports a range of synchronous protocols on the serial interface, and transfers data to and from the host by DMA transfer. This section describes the way in which the DSV11 handles data. On Sat, Jan 29, 2022 at 3:49 PM Chris Zach via cctalk wrote: > > Maybe that is the dhv11. Or the dv11 I'll look it up tomorrow > > On January 29, 2022 5:12:41 PM EST, Paul Koning via cctalk > wrote: > > > > > >> On Jan 29, 2022, at 3:58 PM, Noel Chiappa via cctalk > >> wrote: > >> > >>> From: Paul Koning > >> > >>> DH-11 is unusual in that it has DMA in both directions > >> > >> McNamara's DH11? (I don't know of another DECdevice of that name.) Per: > >> > >> > >> http://www.bitsavers.org/pdf/dec/unibus/EK-ODH11-OP-002_DH11_Asynchronous_16-line_Multiplexer_Users_Manual_Sep76.pdf > >> > >> it's DMA on output only; the input side has a FIFO that has to be emptied > >> by the CPU. > > > >Oh. That's amazing, all these years I thought it had DMA both ways. > >Clearly not. I wonder how I got that misunderstanding. > > > > paul
Re: What was a Terminal Concentration Device in DEC's products?
Maybe that is the dhv11. Or the dv11 I'll look it up tomorrow On January 29, 2022 5:12:41 PM EST, Paul Koning via cctalk wrote: > > >> On Jan 29, 2022, at 3:58 PM, Noel Chiappa via cctalk >> wrote: >> >>> From: Paul Koning >> >>> DH-11 is unusual in that it has DMA in both directions >> >> McNamara's DH11? (I don't know of another DECdevice of that name.) Per: >> >> >> http://www.bitsavers.org/pdf/dec/unibus/EK-ODH11-OP-002_DH11_Asynchronous_16-line_Multiplexer_Users_Manual_Sep76.pdf >> >> it's DMA on output only; the input side has a FIFO that has to be emptied by >> the CPU. > >Oh. That's amazing, all these years I thought it had DMA both ways. Clearly >not. I wonder how I got that misunderstanding. > > paul > -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
Re: What was a Terminal Concentration Device in DEC's products?
> On Jan 29, 2022, at 3:58 PM, Noel Chiappa via cctalk > wrote: > >> From: Paul Koning > >> DH-11 is unusual in that it has DMA in both directions > > McNamara's DH11? (I don't know of another DECdevice of that name.) Per: > > > http://www.bitsavers.org/pdf/dec/unibus/EK-ODH11-OP-002_DH11_Asynchronous_16-line_Multiplexer_Users_Manual_Sep76.pdf > > it's DMA on output only; the input side has a FIFO that has to be emptied by > the CPU. Oh. That's amazing, all these years I thought it had DMA both ways. Clearly not. I wonder how I got that misunderstanding. paul
Re: What was a Terminal Concentration Device in DEC's products?
> From: Paul Koning > DH-11 is unusual in that it has DMA in both directions McNamara's DH11? (I don't know of another DECdevice of that name.) Per: http://www.bitsavers.org/pdf/dec/unibus/EK-ODH11-OP-002_DH11_Asynchronous_16-line_Multiplexer_Users_Manual_Sep76.pdf it's DMA on output only; the input side has a FIFO that has to be emptied by the CPU. Noel PS: I am familiar with the term 'terminal concentrator' from the networking world, but as a generic term, not the name of a particular product. (Although Cisco's first boxes may have included a terminal concentrator, so named.) Noel
Re: What was a Terminal Concentration Device in DEC's products?
> On Jan 29, 2022, at 12:28 AM, Chris Zach via cctalk > wrote: > > Old question: I'm looking through some old reports from 1977 about a failed > DEC project with the DMX11 multiplexer system and there is reference to the > following key items: > > 1) The DMX was designed to handle block mode devices. Fine. > 2) Character mode devices like the VT52's were supposed to use a "TCD" > product from DEC. > > The reason the project imploded was because apparently DEC stopped supporting > the TCD in RSX11/D in late 1976, so someone in CSS had the great idea of > agreeing to extend the microcode in the DMX11 to handle both block AND > character mode devices. This did not work well and it sank the project. > > What I'm wondering is what was the TCD for PDP11's back then? I don't see > anything in my communications handbooks on this, and even the DMX11 doesn't > really appear, instead there is the COMM/IO/P type boards which worked with a > pile of DZ11's. From what I can glean from this documentation it looks like > the DMX11 worked in a similar fashion as the requirement was the DMX11 system > was a nine board solution (possibly 8 DZ11's and one controller board). > > More odd it looks like the TCD *was* still supported in RSX11/M and > ultimately the decision was made to build the thing in M so it's weird they > continued to whack away at the DMX solution instead of going with TCD's for > async and proven DMX microcode for block devices. > > Any thoughts, or does this jog any memories? Nothing comes to mind here; the name "DMX" does not ring any bells. It's a bit before my time, admittedly. DEC made some products that used block mode terminals: the moderately successful Typeset-11 with the VT-61/t forms and page editing terminal, and the VT-71 with embedded LSI-11 to do full file local editing. Both have some form of block transfer to the host, but as far as I can remember they used ordinary DH-11 terminal interfaces. DH-11 is unusual in that it has DMA in both directions, which is unhelpful for interactive use but great for block transfer. Typeset-11 also supported a specialized terminal made by Harris (the 2200), another local processor device, this one connected to the PDP-11 host with a DL-11/E, using half duplex multidrop BISYNC with modem signal handshakes. I kid you not... I have some scars debugging that protocol at 2 am in downtown Philadelphia. DEC also built yet another VT-51 variation, the VT-62, which was the terminal for the TRAX system. That was, I think, some sort of RSX derivative (-M+ perhaps, but I'm not sure), which made it to field test but was canceled before becoming an official product. Not sure why. paul
