Compression support

[Speeddymon]

In addition to ECM, it would be nice if you could add compression support for the big 3 formats, zip, rar (single archive), and 7zip (single archive), so that we could mount compressed images. I wouldn't mind it taking longer to load the image, while it decompresses the data, as long as I knew the data would be deleted once unmounted. Perhaps status message saying "Please wait while Daemon Tools decompresses the image (this may take several minutes)" would help to alleviate "Daemon Tools froze when mounting my compressed image!" posts.

[Fappy]

If you're worried about space, just enable compression on your hard drive. Double space should help you out in that field.

[Novecento]

sorry for bringing up this old topic but I just noticed that the inbuilt Image compression of DT Pro is kinda weak.. would it be possible to include different compression algorithms into DT Pro? The current one doesn't really seem to be that strong..

[LocutusofBorg]

maybe we will include in a later version improved compression
algorithm, however, keep in mind that we have some limitations
to deal with and therefore you would hardly see any cp-ratio
compared to that of e.g. winrar in best compression mode.

Apart of this you can imagine that it would need alot of additional
time to compress.

The current solution is some kind of compromize between cp
ratio and speed - and therefore total efficiency

[mastermind]

The current compression is absolutely brilliant for creating so-called "maxi images". For instance, my .mdf for C&C3 fills up about 4 kB.

But of course, I agree that for regular images the current compression is relatively weak. If we are to get a more powerful compression in the future, I hope that it will be possible for the user to choose compression mode. That way, the user can to some degree choose the compression vs. speed ratio, depending on the situation and needs.

[evlncrn8]

yeh but too high compression (ie: high cpu load) can throw off sector timings, which could result in the image not working, its a very tricky area...

so personally i'd say compress the images when not using (to save disk space or whatever, but considering hdd prices nowadays are low compared to a few years ago this is a relatively weak point to use in the compression 'argument')... otherwise leave them as is..

just my 2c, but i honestly think the dt team could spend their time much better on other things than working on the compression stuff, and possibly breaking things in the long run...

[,jACkdA\W]

Your typical PC game or app data disk crammed with Installshield cabinets is not going to get compressed much with best RAR or 7-Zip modes either The DT compression thingy is handy when you're dealing with Playstation disks or ten-to-fifteen-years-old stuff, it won't normally make a big difference on the 'common' PC disks these days... since better compression would mean more load for the CPU on decompressing and in most cases not deliver *really* increased compression ratio (i don't care for 10%, really ), i am quite happy with the status quo.

[mastermind]

Good points, but remember that there exists all kinds of disc contents. Not all discs you would image are game discs. Imagine compressing discs with tons of documents/documentation. That said, when using other compression formats with other imaging tools (or also rar/zip/bzip2), I've been able to compress standard software installation discs quite a bit.

The argument that storage has become so cheap that it no longer matters, isn't a very strong point IMO. If you become more sloppy with conserving space every time you aquire more disk space, you will in reality not have gained much by expanding your disk capacity. And buying new storage will then actually have been pretty much money out the window and not cheap at all. In addition, remember that the more storage you use, the more your backup needs increase, increasing the total cost.

[,jACkdA\W]

Good points, but remember that there exists all kinds of disc contents. Not all discs you would image are game discs.

You're right of course, but DT's main purpose is not to be the Universal Disk Compressor... f.e. you can get really interesting compression ratios using UHARC on MPEG files, or using FLAC on audio tracks, and of course using almost anything on plain text data - but you better NOT try to use UHARC on an audio disk - more 'serious' compression would mean to incorporate a variety of algorithms for different purposes, as in this example. And to either let the user decide on which to use or waste some more time and build the 'DT-UDC Intelligent Auto-Analyzer'... i see a truckload of work for the support section coming up, as in 'DT not mount .cbr format u mofos fix bugg?' and the likes... anyway, the current compression is WAY good enough for 'uncompressed data' like plain text, for one - check the differences with such a disk against .rar or .7z, it's *not* that much, .rar will yield more but just barely so in my experience (i already said i ignore figures like '10%' in this case ). And how-mighty-ever my processor might ever be, i do not look friendly upon apps which clog up the entire system just because they *think* they *have* to do *this* right now and NO the gods will *not* stop me from doing it dear sir... if you have streaming content on the disk in question (playstation comes to my mind again), the higher CPU load because of more complex compression(s) could actually be more than just an annoyance. I have got one PS2 disk right now, it's acvtually 2.74 GB in size, but... DT's image compression made that a whopping 423 MB Alright, this one *is* an extreme case, but i know for a fact that WinRAR or 7-Zip can *not* do better with this one (they get 10MB more out of it... yeah, right)

The current solution is some kind of compromize between cp
ratio and speed - and therefore total efficiency

I'll just plain second that. You want more 'serious' compression, you CAN already get it... IF it makes any sense, that is. So *storage* should not be a point... and if it's about the 'right-out-of-the-box' usage with direct mounting of archives of disks, keeping in mind the streaming and stuff, on second thought i'll not only second but third that Borg

[mastermind]

anyway, the current compression is WAY good enough for 'uncompressed data' like plain text, for one - check the differences with such a disk against .rar or .7z, it's *not* that much, .rar will yield more but just barely so in my experience (i already said i ignore figures like '10%' in this case ). And how-mighty-ever my processor might ever be, i do not look friendly upon apps which clog up the entire system just because they *think* they *have* to do *this* right now and NO the gods will *not* stop me from doing it dear sir...

I agree that if a stronger compression mode should be introduced in DT Pro in the future, it should be possible for the user to choose compression mode.

I am however not so concerned with compression speed, as I usually keep my images for many years ahead, and how many minutes extra it takes to create the image doesn't make any difference to me. I'm more concerned with the decompressor's impact on performance during usage. If it would have a considerable impact on performance, I would avoid using it on game discs for example.