Re: Seeking enlightenment regarding Bus Adapter Purges on Unibus VAXen (and their ilk)

2019-09-06 Thread Ethan Dicks via cctalk
On Fri, Sep 6, 2019 at 4:32 AM Matt Burke via cctalk wrote: > I'm not sure if the adapter needs to request the purge at the end of > each block transfer. The driver may do this anyway but I'll have to > check the source listings. I would definitely check source listings. Also, check BSD/Ultrix _

Re: Seeking enlightenment regarding Bus Adapter Purges on Unibus VAXen (and their ilk)

2019-09-06 Thread Al Kossow via cctalk
On 9/5/19 9:22 PM, Josh Dersch via cctalk wrote: > I have a pretty good grasp of > Unibus mechanics these days but I'm not quite understanding the reasoning > behind this. Here's what the Storage System Unibus Port Description > (AA-L621A-TK) document says: you might also want to ask on the si

Re: Seeking enlightenment regarding Bus Adapter Purges on Unibus VAXen (and their ilk)

2019-09-06 Thread Matt Burke via cctalk
On 06/09/2019 05:22, Josh Dersch via cctalk wrote: > What I do not understand is (a) why such purges are necessary, and (b) how > the MSCP controller knows when one should occur. The Port Description doc > hints that it has to do with repeated access to a given area of memory. > The DW780 document

Seeking enlightenment regarding Bus Adapter Purges on Unibus VAXen (and their ilk)

2019-09-05 Thread Josh Dersch via cctalk
Hi all -- Been working on an MSCP implementation for Joerg Hoppe's Unibone project, and it's working well on PDP-11 systems; less well as of late on the VAX. I've been looking to tidy up a few dark corners in the MSCP spec and one thing that's left is bus adapter purges -- I have a pretty good gra