rm'ing an open file (was Re: Where has all my disk space gone?)

[Ken Weaverling]

In article <1991Apr23.174228.11278 at aucs.AcadiaU.ca> in comp.unix.questions
       peter at aucs.acadiau.ca (Peter Steele) originally writes:

>df reports the following:
>
>/dev/dsk/ipc1d2s3           ffs  945670  589136  356534  62%  /u2
>
>According to this, we have 589136 kbytes in use on this drive. However,
>du does not seem to agree with df:
>994268  /u2
>
>The total of 994268 blocks in use converts to 497134 kbytes, a difference
>of 92002 kbytes--not a small amount.

Gee, looks like you need Norton Utils for Unix! :-)

I have had something similar happen. I had 10% of disk in use then suddenly
the console was screaming the disk was full. Never knew why. I shut the
partition down and ran fsck and it recovered the missing space...

Must have been a PC virus... :-)    <<<==< READ: *BIG* TIME sarcasm!

But the reply below is my real reason for replying....

In article <1991Apr23.194511.29646 at Think.COM> 
     barmar at think.com (Barry Margolin) replies:

>If a process opens a file and then deletes it, the file still exists on
>disk until all the processes that have it open either close it or die.

God, this took a while for me to get used to. 
  
  process phredd opens file foo
  process phredd puts a write lock on file foo
  process phredd reads data from foo
     process phrogg removes file foo -- even though file is opened and locked
	ls doesn't see foo in directory
     process phrogg recreates file foo
     process phrogg writes data to file foo
  process phredd rewinds file foo
  process phredd re-reads data and gets original data from "non-existant" file!

It makes you have to do ugly things like make LOCK files and have all 
processes look for them. Gack....  

(followups to comp.unix.programmer)
-- 
>>>---> Ken Weaverling  >>>---->  weave at brahms.udel.edu