[Jprogramming] Insert zeroes into large data file

[Sherlock, Ric]

---Randy MacDonald wrote:
> Interesting numbers.  My next questions would be: how modern are the
> drives, and how much RAM is on the machine?  Also, how long
> did the OP's
> 'slow' process take?  Did an actual copy occur?  I could see *nix
> systems doing some inode magic.

Numbers were obtained on a Toshiba Tecra M9 laptop, bit less than a year old, running Vista SP1 with 2GB of RAM. The fcopynew verb from the files.ijs script does a fread & then an fwrite which suggests to me that an actual copy was done.

What numbers did you get on your machine?


> Sherlock, Ric wrote:
> > ---Randy MacDonald wrote:
> >
> >> By copy, I don not mean duplicating a reference. I mean having two
> >> identical sets of bytes where there was one before.  What the
> >> OP seemed
> >> to be talking about was a filter of some sort.
> >>
> >> I based my estimate on 134MB being a 2 hour mp3, or a
> >> 6-minute video.  I
> >> just thought the data transfer speed of a hard drive would
> work out to
> >> about a minute, or 4MB/sec, since both to and from storage
> are what we
> >> are talking about here.  (note to self:  Google 'hard drive
> >> throughput'
> >> for more info)
> >>
> >>
> >
> > The following seems to suggest that 1 minute would be excessive?
> >
> >    6!:2 '(134125010$''abcdefg'') fwrite jpath ''~temp/testsz.txt'''
> > 6.27771190193
> >    6!:2 '(jpath ''~temp/testsz2.txt'') fcopynew jpath
> ''~temp/testsz.txt'''
> > 4.60973992505