Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!pasteur!ucbvax!hplabs!hpda!hpcuhb!hpsmtc1!swh
From: swh@hpsmtc1.HP.COM (Steve Harrold)
Newsgroups: comp.sys.ibm.pc
Subject: Re: File creation error
Message-ID: <11470052@hpsmtc1.HP.COM>
Date: 3 Mar 89 16:59:40 GMT
References: <7852@ihlpf.ATT.COM>
Organization: Hewlett Packard, Cupertino
Lines: 23

Re: Slow COPY to floppy

The reason that COPYing a lot of files to floppy takes a long time is
because the directory on the floppy has to be sequentially searched every
time a new file is added, to guard against duplicate file names.

Since the original sector/cluster allocation for the directory was probably
insufficient to accomodate the hundreds of file names, it was automatically
extended everytime it filled up.  Because you were allocating clusters for
the files being copied, the directory extensions are not adjacent to the
original directory clusters.  This means the directory is fragmented.

Now, take the case of the last file that was COPYed.  The file system
started searching the directory for a possible hit, and caused the
seek arm of the floppy to go all over the place as it serially searched
that directory.  Only then did the copy operation proceed (after yet
another seek) and then the file was closed.  During the close, the directory
was searched again to find the entry so that the new filesize field could
be updated.  A lot more seeks thus occur.

In short, most of the I/O time on the floppy was spent seeking, not writing.

To speed things up, consider COPYing to multiple directories on the floppy.