Re: [Simh] Limits on MSCP controllers

> On Jun 24, 2019, at 5:27 PM, Timothe Litt wrote: >> > As is often the case, things turn out to be complicated. Here's a more > detailed version. In an off-list note, Bob pointed out that MSCP originated > in a project he managed that was to develop the "next generation" disk >

Re: [Simh] Limits on MSCP controllers

On 24-Jun-19 15:18, Clem Cole wrote: > > > On Mon, Jun 24, 2019 at 2:13 AM Timothe Litt > wrote: > > >> > MSCP is basically an evolution of the Massbus protocol, on a > different PHY, and informed by the TOPS-10/20 experiences with > high-end  (large, redundant,

Re: [Simh] Limits on MSCP controllers

On Mon, Jun 24, 2019 at 2:13 AM Timothe Litt wrote: > > > MSCP is basically an evolution of the Massbus protocol, on a different > PHY, and informed by the TOPS-10/20 experiences with high-end (large, > redundant, on-line serviceable) configurations. > That was certainly my impression/memory.

Re: [Simh] Limits on MSCP controllers

A related oddball question I always had about the M9058 breakout board. It would appear that it could support four hard drives and one floppy. BUT the RQDX3 manual says that RQDX3 itself maxes out at 4 drives. If anyone has ever tried RQDX3 + M9058 + Four Drives + Floppy it would be something to

Re: [Simh] Limits on MSCP controllers

On Monday, June 24, 2019 at 12:32 AM, Johnny Billquist wrote: > My point was simply that getting the response back that simh only allows > 4 disks per controller because that was what the real hardware allowed is a > rather bad answer (in my opinion), especially since simh don't even follow > what

Re: [Simh] Limits on MSCP controllers

My point was simply that getting the response back that simh only allows 4 disks per controller because that was what the real hardware allowed is a rather bad answer (in my opinion), especially since simh don't even follow what the real hardware did when looking at tmscp. There, the

Re: [Simh] Limits on MSCP controllers

On Sunday, June 23, 2019 at 4:51 PM, Jonathan Welch wrote: > The system that I set up for myself and for my friend (who needs one more > disk than I do) was cloned from a VMS Cluster that has been in continuous > operation in its present form for about 20 years, so the issue is not with > mounting

Re: [Simh] Limits on MSCP controllers

On 23-Jun-19 20:01, Johnny Billquist wrote: > > Timothe Litt clearly knows this better than I do. His mention of the > attention message jogged my memory a bit. There are just notifications > going the other way about available disks. And ports are not really > relevant. In RSX, they are then

Re: [Simh] Limits on MSCP controllers

> The KFQSA, M7769. > Bob P.S. If anybody has a rack mount DSSI enclosure they'd like to part with, let me know. All I have is the R400x, which wastes valuable floor space and doesn't go with the rack mounted uVAX... ___ Simh mailing list

Re: [Simh] Limits on MSCP controllers

> Johnny Billquist wrote: >What about the DSSI controller which talks MSCP on the Qbus? > I can't remember the name of it. But I'm not > sure if that one was limited to just four disks. The KFQSA, M7769. Supports up to seven DSSI drives. I have one in a MicroVAX-III system. It's a pain to

Re: [Simh] Limits on MSCP controllers

On 2019-06-24 01:37, Johnny Billquist wrote: On 2019-06-23 19:30, Bob Supnik wrote: If you want to extend the current RQ simulator to include third party boards (either SMD-based emulators or SCSI-based emulators), feel free to add an appropriate mode switch. I don't know what controller ID

Re: [Simh] Limits on MSCP controllers

The system that I set up for myself and for my friend (who needs one more disk than I do) was cloned from a VMS Cluster that has been in continuous operation in its present form for about 20 years, so the issue is not with mounting disks too early in the startup sequence. Not that this helps much

Re: [Simh] Limits on MSCP controllers

On 2019-06-23 19:30, Bob Supnik wrote: The four ports is not arbitrary. SimH simulates actual hardware. DEC never built a backplane MSCP controller with more than four ports. I'm not entirely sure about that. What about the DSSI controller which talks MSCP on the Qbus? I can't remember the

Re: [Simh] Limits on MSCP controllers

On 23-Jun-19 13:30, Bob Supnik wrote: > The four ports is not arbitrary. SimH simulates actual hardware. > DEC never built a backplane MSCP controller with more than four ports. > I think that's true for the U/Qbuses.  However, the KDM70 (XMI, last I knew not emulated by SimH) has eight

Re: [Simh] Limits on MSCP controllers

The four ports is not arbitrary. SimH simulates actual hardware. DEC never built a backplane MSCP controller with more than four ports. If you want to extend the current RQ simulator to include third party boards (either SMD-based emulators or SCSI-based emulators), feel free to add an