The snapshot archive available at this web site
contains snapshot data from the virtual12 file
server from October 15, 1994.  

The snapshots are contained in a directory called
'15Oct94.'  This directory contains a separate 
sub-directory for each file system, labeled 
with the name of the file system's device node.
For example, 15Oct94/sd2g contains the snapshot
of the glan5 file system.  The file 15Oct94/df.out
contains output from the df program at the time the
snapshots and can be used to translate device nodes
to file system names.

The directory for each file system contains
three files:

blks.raw.Z  	

This contains the data describing every file
on the file system.  The output is a series
of lines of ascii data.  There are three
types of lines, differentiated by the initial
character of each line.

    D bsize fsize maxcontig rotdelay rps nsect ncyl ntrak spc

	There is one D line per snapshot.  It is the
	first line of the snapshot file and describes
	the disk and file system parameters

	bsize = file system blocks size in bytes
	fsize = file system fragment size in bytes
	maxcontig = value of maxcontig parameter
	rotdelay = value of rotdelay parameter
	rps = rotations per second
	nsect = number of sectors per track
	ncyl = number of cylinders
	ntrak = number of tracks
	spc = sectors per cylinder

    I number gen type size ctime

	There is one I line per inode.  It describes
	the file corresponding to the inode.

	number = inode number
	gen = generation number
	type = file type.  This is a text field.  Values
		include REG, DIR, LNK, and FIFO.  Device
		nodes are not included in the snapshot.
	size = file size in bytes.
	ctime = last time inode was modified.  This is
		expressed in UNIX time format (i.e., number
		of seconds since midnight 1/1/70 GMT).

    C block size

	There are zero or more C lines following each I line
	Each C line corresponds to a cluster of data blocks
	belonging to the file.  

	block = block number of beginning of cluster.
	size = number of blocks in cluster.  If the file
		ends with a fragment, the cluster size is
		rounded up to an integral number of blocks.
		The size of the fragment can be determined
		from the file size.

cg.map.Z

This contains the free space bitmaps from the
file system.

The file has one line for each of the file system's
cylinder groups.  The format of each line is:

    A x F y A z F ...

This translates to say that the first x blocks of the 
cylinder group are allocated, the next y are free, the
next z are allocated, and so on.  If the first block
of the cylinder group is free, then the line will start
with an F.  Partially allocated blocks (i.e., blocks
that have fragments allocated from them) are counted as
allocated.

blks.stats

This contains a brief text description of a few
parameters of the file system.  This file was
used early on in the development of the snapshot
software.  Recently I've completely ignored it.
See the sources of the snapshot program (fsblks)
for a complete description of the contents of this
file.