Path: utzoo!attcan!uunet!samsung!xylogics!westford.ccur.com From: loverso@westford.ccur.com (John Robert LoVerso) Newsgroups: comp.sys.encore Subject: Re: Umax 4.3 virtual memory problem Message-ID: <9922@xenna.Xylogics.COM> Date: 19 Sep 90 04:02:07 GMT References: <1479@sirius.ucs.adelaide.edu.au> <1990Sep18.210722.206@cunixf.cc.columbia.edu> Sender: loverso@Xylogics.COM Reply-To: loverso@westford.ccur.com (John Robert LoVerso) Organization: Concurrent Computer Corp, Westford MA Lines: 24 In a recent article, Alan Crosswell writes: > Again, understandable > that Encore ran into problems parallelizing a non-parallel kernel > design, but some things need to get fixed -- even if it means > scrapping the 4.3 kernel and dropping Mach in instead. Note: The "4.3" here should only refer to the UMAX4.3 kernel, which, in turn, should not be confused in any way with a parallelized version of the 4.3BSD kernel. UMAX4.3 only provides 4.3BSD-like kernel features over a base UMAX"4.2" kernel (VM, process control, etc) - it is not a "port" of the 4.3BSD kernel. [The kernel network code is a major exception to this]. That base kernel is still a reflection of the original (1985) design for UMAX. This is not to say that design is wrong (which would be wrong to say, because it mostly works!), but rather to point out that some continuing problems - such as VM - are because of the original design. As for a future UMAX4.x with MACH parts transplanted in: I place my chips on a sysV.4 UMAX to replace the current UMAXV and UMAX4.3... -- John Robert LoVerso Home: john@loverso.loem.ma.us Concurrent Computer Corp Work: loverso@westford.ccur.com RTU Network Group - FDDI project "No terminal servers, thank you".