nakamoto@joplin.mpr.ca (Alan Nakamoto) (03/29/90)
I am currently trying a Beta version of some software for the Decstation 3100. On the instructions, it tells about a problem in the paging algorithm in Ultrix which causes virtual memory accesses that will put the machine into some kind of paging loop. When I tried the software, some of the things that I tried which would require virtual memory access did cause this problem. Looking at the monitor program revealed many page ins but few page outs. The disk was spinning away with little (0.4%) CPU activity being recorded on the DECstation. My question is, has anybody experienced this problem, heard of it, or heard of a solution. I vaguely recall that there was some discussion of a similar problem in comp.sys.dec or comp.unix.ultrix but don't recall what became of it. If someone has a record of this discussion or any other info, it would be greatly appreciated if they could e-mail me. Thanks, Alan Nakamoto Pacific Microelectronics Centre Burnaby BC. (604)-293-6052. ...!uunet!ubc-cs!mpre!nakamoto
grr@cbmvax.commodore.com (George Robbins) (03/29/90)
In article <2112@kiwi.mpr.ca> nakamoto@joplin.mpr.ca (Alan Nakamoto) writes: > > > I am currently trying a Beta version of some software for the Decstation > 3100. On the instructions, it tells about a problem in the paging > algorithm in Ultrix which causes virtual memory accesses that will put > the machine into some kind of paging loop. When I tried the software, > some of the things that I tried which would require virtual memory > access did cause this problem. There are alledgedly some problems with the Ultrix paging mechanism such that it doesn't page effectively when there isn't enough memory. It's not clear exactly what the DEC position on the problem is, but the only effective workaround I've heard of is to add more memory. This would typically mean expansion to 24Mb for a windowed environment, perhaps 16MB otherwise. It might be that the problem is addressed in Ultrix 3.1C which runs on the 3100 but isn't "supported" in the 3100/UWS environment. On the other hand, it might not make a bit of difference. As far as I know the only effective option is to add memory, though if you have software support, you might attempt to log it as a critical problem (software problem makes it impossible to effectivly utilize system) and see if you get any satisfaction. -- George Robbins - now working for, uucp: {uunet|pyramid|rutgers}!cbmvax!grr but no way officially representing: domain: grr@cbmvax.commodore.com Commodore, Engineering Department phone: 215-431-9349 (only by moonlite)