Re: [Simh] The Interconnect Task Force
(Hooray for automatic spell correction...) On 2019-06-27 11:02, Johnny Billquist wrote: I'm pretty sure the ones I ever saw had so or sti and were connected to an hsc. so was meant to be sdi. So, sdi or sti is what I seem to remember ours had. I think we might still have one or two drives somewhere, but we don't have any media... Johnny Johnny Matt Burke skrev: (27 juni 2019 09:58:14 CEST) On 26/06/2019 04:28, Robert Armstrong wrote: Thanks, but I was more interested in the details of LESI if they are available. LESI was another mass storage "bus" that supported both disk and tape (albeit with exactly one example of each). There is also the RV20 write-once optical drive which used LESI. Matt Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh -- Skickat från min Android-enhet med K-9 Mail. Ursäkta min fåordighet. ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: b...@softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] The Interconnect Task Force
Maybe there was an upgrade kit for the RV20 like the TU81 to TA81 kit which converts it from LESI to STI.Internally the RV20 appears to use SCSI.MattOn 27 Jun 2019 10:02, Johnny Billquist wrote:I'm pretty sure the ones I ever saw had so or sti and were connected to an hsc. Johnny Matt Burke skrev: (27 juni 2019 09:58:14 CEST) On 26/06/2019 04:28, Robert Armstrong wrote: Thanks, but I was more interested in the details of LESI if they are available. LESI was another mass storage "bus" that supported both disk and tape (albeit with exactly one example of each).There is also the RV20 write-once optical drive which used LESI.MattSimh mailing listSimh@trailing-edge.comhttp://mailman.trailing-edge.com/mailman/listinfo/simh-- Skickat från min Android-enhet med K-9 Mail. Ursäkta min fåordighet.___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] The Interconnect Task Force
I'm pretty sure the ones I ever saw had so or sti and were connected to an hsc. Johnny Matt Burke skrev: (27 juni 2019 09:58:14 CEST) >On 26/06/2019 04:28, Robert Armstrong wrote: >> Thanks, but I was more interested in the details of LESI if they are >> available. LESI was another mass storage "bus" that supported both >disk and >> tape (albeit with exactly one example of each). >> >There is also the RV20 write-once optical drive which used LESI. > >Matt > >___ >Simh mailing list >Simh@trailing-edge.com >http://mailman.trailing-edge.com/mailman/listinfo/simh -- Skickat från min Android-enhet med K-9 Mail. Ursäkta min fåordighet.___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] The Interconnect Task Force
On 26/06/2019 04:28, Robert Armstrong wrote: > Thanks, but I was more interested in the details of LESI if they are > available. LESI was another mass storage "bus" that supported both disk and > tape (albeit with exactly one example of each). > There is also the RV20 write-once optical drive which used LESI. Matt ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] The Interconnect Task Force
Update have both a plain tu81 and an tu81+, so they certainly exists. Johnny Robert Armstrong skrev: (27 juni 2019 01:30:53 CEST) >> Johnny Billquist wrote: >>Wasn't both the TK50 and TU81 using LESI? > >TU81+ was definitely LESI. Same KLESI controller; just change the CSR >to the TMSCP address rather than the disk MSCP. > >I never saw a TU81. Don't know if such a thing actually >existed or not. > > The TK50/TK70 was certainly NOT LESI. > >Bob -- Sent from my Android device with K-9 Mail. Please excuse my brevity.___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] The Interconnect Task Force
> Johnny Billquist wrote: >Wasn't both the TK50 and TU81 using LESI? TU81+ was definitely LESI. Same KLESI controller; just change the CSR to the TMSCP address rather than the disk MSCP. I never saw a TU81. Don't know if such a thing actually existed or not. The TK50/TK70 was certainly NOT LESI. Bob ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] The Interconnect Task Force
On 2019-06-26 05:28, Robert Armstrong wrote: RC25 ... Thanks, but I was more interested in the details of LESI if they are available. LESI was another mass storage "bus" that supported both disk and tape (albeit with exactly one example of each). Wasn't both the TK50 and TU81 using LESI? (Along with the RC25.) Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: b...@softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] The Interconnect Task Force
> RC25 ... Thanks, but I was more interested in the details of LESI if they are available. LESI was another mass storage "bus" that supported both disk and tape (albeit with exactly one example of each). RC25s never worked which, if you had an 11/725, was sad :( Bob ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] The Interconnect Task Force
> On Jun 25, 2019, at 7:42 PM, Bob Supnik wrote: > > The RC25 (code named Aztec) got started as I was leaving Storage Engineering. > ... > > The RC25 was pretty much a disaster, technically and financially, and the end > of the line for DEC's removable disk program. It was quite ugly, because you had two drives on one spindle. RSTS was told to support an RC25-only config, apparently for use in Royal Navy submarines (space constrained, obviously). The trouble is that removing the removable pack meant spinning down the system unit (boot drive). RSTS was never designed for that and would get very unhappy. We hacked this by basically putting a system freeze feature in that would let you freeze everything while the drive was off. paul ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] The Interconnect Task Force
The RC25 (code named Aztec) got started as I was leaving Storage Engineering. Mike Riggle, VP of Storage Advanced Development (and later Storage Engineering), recognized early on that to improve seek and rotational performance, disk diameters (14" for the RA8X series) had to shrink; 8" or 9" would be the next target. Mike wanted to do only sealed (Winchester) disks, but there was significant marketing pressure for a low-end removable disk to succeed the RK11, RK611, and RL11. Hence Aztec, later the RC25. LESI was, I believe, an attempt to cost-reduce the RA8X's radial disk interconnect while maintaining performance. The RC25 was pretty much a disaster, technically and financially, and the end of the line for DEC's removable disk program. Low end systems went with ST504-compatible 5.25" sealed disks (the RDXX family), while the high-end went with 8" or 9" RA9X series, which used the RA8X radial interconnect. ST504 was eventually replaced by SCSI (and later its clusterable proprietary variant, DSSI). /Bob On 6/25/2019 7:22 PM, Robert Armstrong wrote: Bob Supnik [b...@supnik.org] wrote: Ah, yes, the Interconnect Task Force. 1980, perhaps? Can you say anything about LESI, "Low End Storage Interconnect"? It was used by the RC25 and the TU81+ and, AFAIK, that's it. It never really went anywhere and there's basically no documentation on it that I've ever seen. I always wondered about the story behind that. Thanks, Bob ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] The Interconnect Task Force (was: Origins of MSCP)
> Bob Supnik [b...@supnik.org] wrote: >Ah, yes, the Interconnect Task Force. 1980, perhaps? > Can you say anything about LESI, "Low End Storage Interconnect"? It was used by the RC25 and the TU81+ and, AFAIK, that's it. It never really went anywhere and there's basically no documentation on it that I've ever seen. I always wondered about the story behind that. Thanks, Bob ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
Re: [Simh] The Interconnect Task Force (was: Origins of MSCP)
Ah, yes, the Interconnect Task Force. 1980, perhaps? All my engineering notebooks are entombed at the Computer History Museum now. CI - computer interconnect - realized in the passive "star coupler" and the CIxxx family of interfaces. BI - backplane interconnect - realized in the BIIC chips - used as the memory and IO bus in the 8200 and the IO bus in several further systems. Superseded by the XMI, which was the memory and IO bus of the VAX 6000 family and was later used as an IO bus. NI - network interconnect - Ethernet. Success! DI - device interconnect - intended as a low cost interconnect to devices - basically async serial. Really only used in the DECtape II implementation with its own simplified form of MSCP (Radial Serial Protocol). II - interchip interconnect. This went nowhere at the time. The Semi Group standardized much later on the CVAX pin bus as a defacto "II" and created a family of pin-compatible chips. The CVAX pin bus morphed from a memory-and-IO bus in CVAX to an IO-only bus in later chips. Chips in the "CVAX pin bus family" included the memory controller (CMCTL), the console chip (CSSC), the second-generation Ethernet control (SGEC), the DSSI controller (SHAC), and the Qbus interface (CQBIC). The last three were used across multiple generations; the CMCTL and CSSC were only used in CVAX systems. Superseded, in most senses, by PCI in the 1990s. About the only thing that was consistent in DEC's interconnect strategy was that one generation's memory and IO backplane interconnect became a pure IO backplane interconnect later. This was true of the Unibus, Qbus, BI, and XMI. Memory cards were easy to design and replace; IO controllers tended to live much longer. /Bob On 6/25/2019 1:33 PM, Paul Koning wrote: On Jun 25, 2019, at 11:43 AM, Bob Supnik wrote: True. My first assignment at DEC was managing the "New Disk Subsystem" (NDS) advanced development project, which led eventually to both the HSC50 and the UDA50. Among the goals of the project were 1. To move ECC correction off the host and into the disk subsystem, so that much more powerful and complex ECC codes could be used. 2. To move bad block replacement off the host and into the disk subsystem. 3. To provide a uniform software interface for radically different disk drives. 4. To abstract away all device geometry information. 5. To implement command queuing and to perform all performance optimization, particularly seek optimization, in the disk subsystem. #2 was only partially true in the UDA50 -- I remember an amazingly large body of code in RSTS for bad block replacement for the RA80 that's about 2000 lines of code -- roughly the same size as the rest of the MSCP driver. I remember MSCP as part of the larger "Interconnect Architecture" effort, which produced a range of "interconnects" some of which seemed to become real and some less so. There was the new peripheral bus (BI), the cluter interconnect (CI, computer interconnect) and one or two others. I vaguely remember II (Interchip Interconnect) -- did that become I2C, or something else, or nothing? And DI (device interconnect) ??? Also NI, which became Ethernet. And XI? I think we used that term in the networking group for the next generation high speed network. Gigaswitch? FDDI? Not sure. Part of the impression I had was that there was some overall concept unifying all this, but whether that was actually realistic is not clear. One place it showed up was in the Jupiter mainframe (which didn't happen), supposedly built around CI and NI as its connections to the outside world. There's also XMI, but that was a generation later as I recall. paul ___ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
