The zdelta-1.0 Experimental Results

Experimental results comparing zdelta against vcdiff, xdelta, and gzip.
Three different classes of experiments are presented here.

The first experiment observes the compression performance, achieved compression ratio, and compression/decompression speed on real data. The data for this experiment are the gcc and the emacs data sets from Benchmark1.
The second experiment, observes how the compression parameters are affected by the input data similarity. The data for this experiment are the artificial morph data sets from Benchmark2; the input file size is fixed to 1MB and the file similarity is varied.
The third experiment observes the relation between the input size and the compression/decompression speed. For this experiment again the data are morph data set from Benchmark2; this time the file similarity is fixed, and the file size i s varied.

The experiments presented here were conducted on machines with the following configurations:

Machine I: E450 Sun Enterprise, with 2 ULTRA SPARC ii_e CPU at 400MHz and 4GB of RAM, using 5 SCSI disks with RAID-5 configuration
Machine II: Dell PowerEdge 2400, with 2 P-III CPU at 800MHz and 1GB of RAM, using 5 SCSI disks with RAID-0 configuration
Machine III: Sun ULTRA 10, with ULTRA SPARC ii_e CPU at 400MHz and 384MB of RAM with 2 IDE Western Digital WD600BB disk drives

For more information on the conducted experiments refer to the results section of zdelta: an Efficient Delta Compression Tool.

Experiment 1

gcc	size	MachineI compress	MachineI decompress	MachineII compress	MachineII decompress	MachineIII compress	MachineIII decompress
uncompressed	27289	-	-	-	-	-	-
gzip	7563	31	18	13	9.0	48	29
xdelta	462	21	15	6.8	5.0	36	29
vcdiff	290	33	16	20	8.9	55	26
zdelta (STDIO)	251	34	17	15	8.8	56	28
zdelta (direct)	251	27	9.6	8.6	2.7	42	17

Compressed sizes and running times for the gcc files (sizes in KB and times in seconds)

emacs	size	MachineI compress	MachineI decompress	MachineII compress	MachineII decompress	MachineIII compress	MachineIII decompress
uncompressed	27327	-	-	-	-	-	-
gzip	8577	36	22	16	12	56	37
xdelta	2132	30	21	10	7.0	51	38
vcdiff	1822	35	21	20	11	58	34
zdelta (STDIO)	1466	44	22	19	11	69	36
zdelta (direct)	1466	35	12	11	3.4	55	22