Description of files found in .../NetBSD-1.3.1/i386/installation/floppies:

All files ending in .fs are NetBSD file systems images intended
to be copied to floppy disks. Please read the INSTALL document to
learn how to use them.

The .gz versions of the files are identical except that they have been
compressed with gzip, the Gnu file compression utility. Note that gzip'ed
files are NOT decompressable with the DOS "unzip" utility that
unpacks .zip files.

boot.fs			Installation/upgrade 1.44M floppy image
boot.fs.gz		The same, compressed with gzip
boot-small.fs		Cut down image for machines with 1.2M floppies
boot-small.fs.gz	The same, compressed with gzip

Every directory contains several checksum files (BSDSUM, CKSUM, MD5, &
SYSVSUM) that contain checksums of all the other files made with the
cksum(1) utility. The MD5 checksums made with "cksum -m" are
considered the "safest", followed by the CKSUM POSIX-style checksums
made with the plain "cksum" command. Please check the integrity of
your distribution against one of these sets of checksums if
possible. The BSDSUM and SYSVSUM files contain checksums made with the
historical BSD and System V checksum utilities and are provided for
those with no other checksum utilities available.