%OP%JUY
%OP%TM2
%OP%BM2
%OP%LM5
%OP%HE/%H2%Z88 Users' Club Software Library
%CO:A,12,72%%H1%%H2%PATPCW.BAS -- A POTENTIAL FIX TO A POTENTIAL PROBLEM


%JR%Cambridge Computer's "Z88 Developers' Notes" says that serious problems 
%JL%can occur if you have a warm reset with a file in :RAM.-.  The obvious 
%JR%reference is to using the []+S function (or any of the []+ CLI's); and 
%JL%the solution is to ERase any RAM.-/S.SGN files you create as soon as 
possible. And I have always done so.

The quote from the Z88 Developers' Notes:

  "The device :RAM.- can use memory from anywhere in the system,
   and as such it is very useful for large files.  Due to a bug in
   the current operating system (version 2.2/3.0) if any files are
   stored in the device when a Soft Reset occurs, the system
   becomes badly confused, and it is very likely that a crash will
   follow sometime later.  If you need to use :RAM.- files, then it
   is vital that they are deleted immediately after use."

%JL%But today I has a lock-up -- happening when I went into filer and tried 
%JR%to Erase a :RAM.-/S.SGN file that was there: No dice!  Even after a 
%JL%Warm Reset, I got this lock-up when trying to kill, or overwrite, a 
S.SGN file. Hmmmm.. why, and what to do?

%JL%I've known for some time that the Basic patches, PATCH.BAS & 
%JR%PATCH2.BAS, create files in :RAM.-  (e.g., f.cli and e.cli).  This 
%JL%*could* be the problem, since it is a little hard to avoid them, while 
using the Basic line editor.

%JL%Tonight I went into the PATCH.BAS program (in my PC) and modified it to 
%JR%write those files to :RAM.0 instead of :RAM.-.  My "patched PATCH" is 
called PATPCW.BAS.

Needless to say, it is not well tested. On the encouraging side:

o The patches were put together in early 1988; I believe the :RAM.- bug
  came to light later.

o There is a BAS program editor CLI as part of an application in the
  Developers' Notes.  It writes the little e.cli files, etc. to :RAM.0

%JL%This is really a "caveat emptor" job.  If you use it, let me know 
%JR%(installs by chaining, just like the original).  Note, that it is 
%JL%PATCH.BAS based -- and does not include the added goodies of 
PATCH2.BAS.

Phil Wheeler -- 1/29/89


%H1%%H2%PATPCW.UPD -- MORE INFO

%JR%Above, I indicated that little testing was done on this revised patch.  
That is no longer the case.

%JL%I've used PATPCW.BAS extensively in its editing mode, with no ill 
effects -- and tested the graphics features.  It works.

In limited testing, PAT2PCW.BAS works fine, too.

%JL%Therefore, I strongly recommend using these modified patches in place of 
%JR%the originals.  They deal with the :RAM.- bug of the Developers' Notes, 
without sacrificing functionality.

Phil Wheeler
17 Feb 1989
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