henry@utzoo.UUCP (Henry Spencer) (06/15/83)
To be more specific than the last news item, the intended purpose of the Monday shutdown is to do the long-discussed compaction of the 44's bus. We've been postponing this because of the steady disk tinkering, but that seems to be pretty much at an end for the moment. (The matter of the new controller remains to be addressed, but I haven't figured out quite what to do about it yet.) The intent is to clean up the Unibus, mostly by eliminating superfluous backplanes and cables. The expander box will leave the system, and all peripherals will reside in the CPU box. The magtape controller's backplane will occupy the position now held by the Versatec-controller backplane in the cpu box. We might move our newest (and presumably electrically cleanest) 9-slot backplane, the Plessey one down in the expander box, up to replace the current 9-slot peripheral backplane in the cpu box. Said backplane will then have all six DZs stuffed into it (this will be the hard part). The disk controller will go in the single hex slot available in the cpu backplane. The line printer controller, the DL for the Sanders, and the papertape controller (the only quad boards we have on the system) will get sort of fitted in around the edges. The major unknowns are whether all the cables will fit through that blasted narrow slot in the back, and how hard it will be to cram the DZs in like that. A secondary worry is whether all the DZ cables will still reach. Star Ring may get put back onto the bus at the same time; I haven't quite made up my mind about that one yet. The only thing that will be lost, apart from a lot of empty space, will be the Versatec. The idea is that Sanders graphics (which is already running on an experimental basis) will replace it. The Sanders is rather slower, and the graphics users won't have it all to themselves the way they have the Versatec, but the output quality is fairly similar even with the current (rather simplistic) Sanders graphics. This will also head off the question of long-term use of the Versatec, which is extremely old and probably beyond effective maintenance, and needs rather expensive paper and toner.