[net.micro.cbm] Save with replace '@:' trashes files ???????

n2ic@druxm.UUCP (05/22/84)

One of the recent articles mentioned that save with replace "@:" trashes
files.

I have never seen this mentioned on the net.

Can anyone fill me in ?????

I use @: very often, and have seen trashed files at times that I couldn't
explain.

Steve London
druxm!n2ic

mab@druky.UUCP (05/22/84)

Never, never, never use the '@:' save with replace command!
It worked fine for me for about a month.  Then all of a
sudden, I had several directory entries pointing at the
same block on disk, and I had lost a large file (I spent a day
poking around the disk trying to recover the lost file,
but to no avail).  I now tediously rename the old file
before saving the new one.  This has the advantage of keeping
several backup copies of the file until I get around to
deleting the old ones.

It's a shame Commodore still documents this command, but of
course I've never seen any good documentation from Commodore.

		Alan Bland, ihnp4!druky!mab
		AT&T-ISL, Denver

joels@tektronix.UUCP (Joel Swank) (05/30/84)

     I investigated the problem with @: saves extensively when I first 
encountered it. I found that the problem never occurs the first time a
directory entry is reused (that's essentially what @: does, re-use the
directory entry for a new file). So it's safe to do it once. It happens
frequently the second time an entry is re-used. The probability is very
high that it will happen on the third @:. The problem is independent of
the file type. There are 3 solutions to the problem: Don't use @: ;
Use it only once on each directory entry; validate the disk after each
@:.

Joel Swank
Tektronix, Beaverton OR