Path: utzoo!attcan!uunet!husc6!bloom-beacon!mit-eddie!ll-xn!ames!pasteur!ucbvax!CITHEX.CALTECH.EDU!carl
From: carl@CITHEX.CALTECH.EDU (Carl J Lydick)
Newsgroups: comp.os.vms
Subject: re: Untabify utility
Message-ID: <880521113956.176d@CitHex.Caltech.Edu>
Date: 21 May 88 18:45:11 GMT
References: <309@ucsvc.unimelb.edu.au>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 13


 > I noticed that TPU would go into infinite loops when I tried to use TAB_IT
 > on large (>300 blocks) files. Does anyone out there know anything about this?

I think so.  I think that what is happening is that TPU is NOT going  into  an
infinite loop, it's just getting VERY slow at doing what you've told it to do.
TPU has fairly severe memory management problems; the symptom  is  exponential
use  of  resources  (CPU  time  and  memory)  as  a  function of the number of
replacements  of  text  done  within  a  single  procedure.   The  first   512
replacements  may  take a fraction of a second.  The 50th 512 replacements may
take several CPU hours, assuming you haven't run out of  virtual  memory  yet.
The workaround for this is to have a separate procedure to do the replacement,
called from the procedure with the main loop in it.