Backup dvd - Hash

Been thinking, you know the acronis backup tool. I’ve read it achives using a hash algorithm. Reason for speed backup and compression to a smaller file.

Hash i take it is like a text document, that compresses very small. Need to know names of softwares that can hash a dvd full of data into a file. So i can 7zip it or ace it, well more than acronis could if it does dvd backup. This i’m hoping would be a good backup method, retaining the original dvd. Better than any shrink or other methods.

Anyone have ideas what sofwares can output full disk in hash code ?

And what hash code algorithm would be best for compression, to make very small backup files ?

I think you have the wrong idea about hash. Examples of hash algorithms are: CRC32, MD5, SHA-1. A hash is a one way ID that is calculated from the data - meaning that you cannot get the data from the ID.

The use of the hash is so that you can check whether the data is corrupted in situations where you cannot store or obtain more than 1 copy of the data. Perhaps an example will help:

Scenario:
You’ve downloaded a large linux CD .iso image (of 600MB) from the internet, but before you burn it to CD-R, how to be more confident that the downloaded file is not corrupted due to the download?

The uploader has calculated a hash value already and is displayed on the website. Just to illustrate this, assume that the hash algorithm is MD5 and this is displayed:
27a4de3117889274d73659354f38a6b3

Solution:
You calculate the MD5 on your downloaded image. If you get a different ID value to above, then the image is definitely corrupted. If you get the same value, then it has a very high probability that the image is not corrupted.

You can calculate the hash value of any file using a tool like:
http://www.slavasoft.com/hashcalc/index.htm

*Note, I’ve used ID to help make it easier for non techies to understand. Correction would be ‘check digits’ or ‘check symbols’ in place of ID.

Sure i understood that, but the patent acronis submitted for there tools says it uses a hash algorithm (i’ll try and find it again soon). I thought it might be something new as of a few years ago, where they could get all the data via some hash. As there are many type of varieties of hash codes.

Ok if that is not the way, what of reading a dvd in different way. Instead of binary someway so it can be compressed down to 1gb or so. I’m not clued up on what code is what the reason for asking in a technical forum, if sollution found would help everyone, more so if made free for all.

Thinking…
So what can binary be converted to, and what is acronis really using to get better compression.

There must be a conversion for computer binary to text like code. For the like of acronis to achive what they do. I also read that an acronis hard drive image is not a true hard drive image (raw). Cannot be used by any other tools except acronis.

Just read that virtualmachine ware (vmware) can use acronis image, so some paths to explore for those that know how. Maybe from learning what it uses it to could be used for dvd backup or improved code be found. Because we really do need a lossless dvd backup archiver, that can achieve small compression file size.

A hash can be used to find errors but it can not be used to reconstruct data (sectors). Find the app that can compress the data (sectors) the most and this is the best you can do. Movies are already in a compressed form so they will not compress much if any.

RM

YEs i agree have been trying just that, hash was the wrong synom to use. I have seen hdd code in other formats (code base). It is that i will look at and do compresion tests. I’m sure finding the right one could be brought over to dvd. Of course hdd and dvd are different but the code is that is stored on it, i’m concerned with.

It’s about compressing further mpeg2 dvd iso just find the right code base.

btw What’s though the best compressor atm for x86 and x64

Maybe just on a never ending ghost hunt, as must have been pursued many time before. Would be nice if found to alleviate our dvd storage problems. Until that is a favourable cheap optical storage is available.

We hear of many brilliant examples of developments and trials, yet nothing comes of it. Even BR sunk fast, there’s no BR cheap drives or disks, like we have with dvd. Who would buy in to such an expensive BR market, if it was favoured we would all be using the daily long ago.

Until then we still need an option for archiving, i should look around the net more. But haven’t the energy or inclination to do so atm. Just through various codes, thinking aloud, and compression testing in hope of a sollution, nothing yet

Looking around for acronis file types again. Ok can be acronis compressed/uncompresed and sector images. one site is said able to convert the images to virtual machine ware by using the converter.

Acronis>hdd>high compression>2.5gb .TIB image (.TIB acronis image extension)
VMWare Converter>2.5.tib (acronis image)>vmware (vmdk image)
VMWare (folder of above vmdk image) >winrar compression (fastest with recovery set at 10) > 1.28gb winrar archive

vmware conveter out put this to one folder (in brackets assumed). This folder i winrar acrhived.
FileName.vmdk (hdd image layout)
FileName-s001.vmdk (part disk image)
FileName-s002.vmdk (part disk imge)
FileName-s003.vmx (vmware mount for the image)