Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!iuvax!purdue!decwrl!ucbvax!janus!kennish From: kennish@janus.uucp (Ken A. Nishimura) Newsgroups: comp.unix.ultrix Subject: Re: Ultrix 3.1 (aka UWS 2.1) memory requirements Message-ID: <30421@ucbvax.BERKELEY.EDU> Date: 5 Aug 89 23:26:43 GMT References: <8908012227.AA24357@garnet.berkeley.edu> <30334@ucbvax.BERKELEY.EDU> Sender: usenet@ucbvax.BERKELEY.EDU Reply-To: kennish@janus.UUCP (Ken A. Nishimura) Organization: University of California, Berkeley Lines: 38 In article grunwald@flute.cs.uiuc.edu writes: > >How much does DECwindows take compare to e.g., the MIT X11R3 distribution? >Why does it take more? > >Since the monochrome PMAX doesn't have a hardware accelerator, I assume >that there's little performance improvement in using DECwindows over >X11R3; am I right? Well, the problem with DECwindows is worse on systems with little core memory. If there is one word to describe DECwindows or as a matter of fact any /usr/bin/dx*, it is HUGE. These are huge binaries, due to the enormous libraries associated with DECWindows. When running DECwindows on a memory starved machine, raising a window or doing any kind of context switch is painful, since it swaps anytime you do something. Plus, it costs a lot in terms of swap space. We found that we had to add another 12MB of swap to accomodate worst case DEC* usage. MIT X11R3 binaries are smaller, so the chance of things getting swapped out at every touch of the keyboard is smaller, plus it saves on virtual memory....plus I don't think it is as CPU intensive in the stuff it does behind the scenes, though I'm not sure about this. As for the PMAX, the color PMAX has no graphics accelerator either (e.g. no dragon chips). The graphics performance of the PMAX is entirely dependent on the R2000a processor. When unloaded, the PMAX will edge out the GPX, but when loaded, the display suffers. The problem with DECW* is worse on PMAXen for two reasons. (1) The binaries are larger. (2) DEC didn't use shared libraries.... Hence, every single /usr/bin/dx* application is 1MB of text. It gets really expensive after a while, especially if you are on an 8MB PMAXen. -ken