2.72 changelog

[DrTeeth]

Would it be possible to have more information on the changes please? For example, what was done to change the compression options?

TIA

DrT (at work so no sig)

[Brian49]

May I amplify this request, please. Several enhanced compression options are offered, but they are simply labelled as A, B, C and so on with no indication of what the letters mean. Many thanks.

[DrTeeth]

Though information has been written in the updated manual about the new compression schemes, I would appreciate some quantitative information. I appreciate that this is difficult, but some comparison with the previous schemes must be possible.

DrT

[TeraByte Support]

You have standard which gives a decent time/size but is inefficient when
dealing with uncompressible data, then the enhanced size options which will
typically produce a smaller file (compress more) but may or may not take
more time depending on data/system/etc.., a, b, c are equivalent
(compatible) to the prior enhanced options. A is faster than C, C
compresses more than A. It's hardly ever worth using C but it's there for
those that do gain enough vs the extra time. d, e, and f are new options
where d is faster than f, f compresses more than d. again using f is hardly
worth using over d. The a,b,c options will give different time/compression
as compared to d/e/f. The time / size differences is going to very on the
data. The enhanced speed options will typically be faster than standard but
not compress as much, a will be faster than b, b will compress more than a.


"DrTeeth" wrote in message news:2507@public.image...

Though information has been written in the updated manual about the new
compression schemes, I would appreciate some quantitative information. I
appreciate that this is difficult, but some comparison with the previous
schemes must be possible.

DrT

[DrTeeth]

Do you have any figures from your tests? I assume that you tested a
given mix of files. I know my/our experience will vary, but it would
be useful to see what your test results were. At least I could make a
judgment to see if it would be worth my while to at least start
testing at my end. I have an avertion to qualitative adverbs .
--

Cheers

DrT
______________________________
We may not be able to prevent the stormy times in
our lives; but we can always choose to dance
in the puddles (Jewish proverb).

[Brian K]

DrT, for what it's worth I did some tests. I created an image using IFW with "None" compression. Let's say the image size was S and the time was T.

Using Standard compression, the results were 0.69 S and 3.0 T

Using Enhanced Speed - A, the results were 0.72 S and 1.1 T

I really like Enhanced Speed - A and that's what I'm now using.

[TeraByte Support(PP)]

In my tests, I saw very little difference in the final image size and a lot of difference in the time taken. The results below don't include all the options, but you can get the general idea. The partition being backed up had 69GB of various data files on it.

Standard 21:45 - 59.9GB
Size A 50:37 - 58.5GB
Size C 2:02:26 - 58.3GB
Size D 29:35 - 58.6GB
Size E 41:28
Size F 55:52
Speed A 12:16 - 60.0GB
Speed B 12:45 - 59.8GB

If you want to check it out on your data without running through them all, you can run Size A & D and Speed A. This will give you a very good idea of what to expect and you can run any of the others if you think it's worth it for you.

Here's another set of results on a clean XP partition:
Standard 1:04 - 1.73GB
Size A 1:40 - 1.59GB
Size B 2:45 - 1.56GB
Size C 3:30 - 1.56GB
Size D 1:01 - 1.62GB
Size E 1:23 - 1.57GB
Size F 2:56 - 1.56GB
Speed A 0:40 1.83GB
Speed B 0:46 1.79GB

[TheKid7]

I did a simple comparison. Windows XP Pro SP3 32 bit, AMD Quad Core CPU, 2 GB RAM

Uncompressed file size reported by IFW: 11.23 GB

Standard Compression:
Image Time: 5:22, byte-by-byte verify: 4:37, Total Time: 9:59
Image File Size: 6.65 (1st size given under Windows Explorer file properties)

Enhanced Speed A Compression:
Image Time: 3:44, byte-by-byte verify: 4:04, Total Time: 7:48
Image File Size: 7.15 (1st size given under Windows Explorer file properties)

[DrTeeth]

Thanks to all who have provided figures. I had also decided on Speed A
as a) size is not that important (Ooer!) and b) time is.
--

Cheers

DrT
______________________________
We may not be able to prevent the stormy times in
our lives; but we can always choose to dance
in the puddles (Jewish proverb).

[TeraByte Support]

Backup using validate byte-for-byte.

Type: backup time / validate byte for byte time / size

None: 26m/25m/196GiB
Standard: 34m/16m/114GiB
Enh A: 53m/16m/106GiB
Enh D: 34m/25m/108GiB
Enh Spd A: 16m/16m/119GiB