Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!world!mkahl
From: mkahl@world.std.com (Michael Kahl)
Newsgroups: comp.os.minix
Subject: Re: macminix
Summary: fix for overwriting low memory
Message-ID: <1991Jan5.031942.446@world.std.com>
Date: 5 Jan 91 03:19:42 GMT
References: <1990Dec22.1046.1132@canrem.uucp>
Organization: The World @ Software Tool & Die
Lines: 32

In article <1990Dec22.1046.1132@canrem.uucp> "glen lalonde" <glen_lalonde@canrem.uucp> writes:
>**** MacMinix upon boot overwrites the address error trap handler
>address in low memory! This will cause a great number of problems,
>since address errors will not drop you into macsbug but will cause
>strange system behaviour. Most of the time the internal drive will
>start to run, for no reason at all, after a little while of runnning
>some bad code it will just crash the system. PLEASE post a fix if
>you know what part of the system is trashing the vector. I think
>it is at 0x0c in memory if I recall correctly.

Here is the fix.  I have no idea what the original code might have been
meant to accomplish, but it's clearly in error.

*** /usr/src/kernel/console.c~	Thu Dec 20 23:00:34 1990
--- /usr/src/kernel/console.c	Thu Dec 20 23:00:59 1990
***************
*** 115,121 ****
    if (scrollrgn == 0)
       scrollrgn = NewRgn();
    vdusetparams(line, 1, monaco, 9, line == 0 ? 1 : 0, 1, 0L, 1, 0, 0);
!   GetNextEvent(GetNextEvent(0, &e));
  }
  
  
--- 115,121 ----
    if (scrollrgn == 0)
       scrollrgn = NewRgn();
    vdusetparams(line, 1, monaco, 9, line == 0 ? 1 : 0, 1, 0L, 1, 0, 0);
!   GetNextEvent(0, &e);
  }