Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!armadillo.cis.ohio-state.edu!lum From: lum@armadillo.cis.ohio-state.edu (Lum Johnson) Newsgroups: gnu.misc.discuss Subject: Re: Why does emacs do so much that is not editing? Message-ID: <59085@tut.cis.ohio-state.edu> Date: 28 Aug 89 21:00:04 GMT References: <19115@unix.cis.pittsburgh.edu> Sender: news@tut.cis.ohio-state.edu Reply-To: Lum Johnson Organization: The Ohio State University, IRCC/CIS Joint Computing Laboratory Lines: 43 In article Bob Sutterfield writes: >In article <19115@unix.cis.pittsburgh.edu> msw@unix.cis.pittsburgh.edu (Matt S Wartell) writes: > ...emacs attempts to do everything... This seems to be counter to > the Unix philosophy of ``a tool should do one job and do it well.'' > >Perhaps you're looking at it wrong - each elisp package is a tool, and >does its single job well. Emacs is just the Lisp interpreter and user >interface veneer that provides a common way to get to them all. A sufficent explanation of the difference in system philosophy between the UNIX operating system and the Emacs virtual operating system is, I think, inherent in the difference in system history: UNIX grew up on a very small machine, the PDP-11 EMACS grew up on a very large machine, the PDP-10 Admittedly, GNU Emacs is written in C and Lisp rather than in assembly language and TECO as ITS/TWENEX Emacs is, but it still has the habits and instincts of a program designed for a very large system. The PDP-10 implements true virtual memory, with paging as well as swapping, so the use of each page of physical memory is individually scheduled for maximum throughput, and unused pages of a program's image do not become resident in memory. A running ITS/TWENEX Emacs image typically uses only about 30 to 35 pages of physical memory - more pages are mapped but not in core. (A page is 512 36-bit words - it will store 2560 7-bit bytes or 2048 9-bit bytes.) The transitions from KI-paging (cf VAX/VMS pre-V4.0) to KL-paging (ca 1972, cf VAX/VMS circa V4.0), and from raw TECO to CTRL/R TECO (Emacs) occurred roughly simultaneously, so Emacs unsurprisingly relies upon free heavy-duty memory management. ITS/TWENEX Emacs does not in fact run on early PDP-10 processor models or under early PDP-10 operating systems (PDP-6's or KA's, or TOPS-10), which lacked this (amoung other things). It is not enough for a machine to be simply "big". Lum (Your "system paleontologist") -=- -- Lum Johnson lum@cis.ohio-state.edu lum@osu-20.ircc.ohio-state.edu "You got it kid -- the large print giveth and the small print taketh away." -------