IMGTool Classic creates fragmented ISO's



I had always heard that burning from an ISO file rather than VIDEO_TS files resulted in higher quality burns so I have been using IMGTool Classic to create ISOs and I burn them with either DVD Decrypter or Nero. I have noticed that when I analyze my drive with Diskeeper Pro, the ISO file that IMGTool creates is always fragmented (all data on seperate drive than OS and on its on IDE). Sometimes as much as 200 fragments according to Diskeeper. So far I have been defraging these files before burning but even as fast as Diskeeper is it can take a bit of time to defrag on big continous file that is heavily fragmented. So my questions are, Can anyone else lend any light onto this? ie is this just a part of the way that IMGTool and other progs create the disc image? And is it necessary to defrag before burning keeping in mind Data integrity is very important to me. Here is my sys info (sys benches great on sandra, hdtach etc)

AMD A64 3200 (Winchester)
Asus A8V Deluxe
Seasonic Super Tornado 400W
1GB Mushkin PC 3200 running at 200mhz DDR
Matrox G400 AGP
Chaintech AV710 PCI soundcard
1 Samsung 160GB on SATA (only drive on channel)
1 Seagate 160GB on HDD Raid (only drive on channel)
1 NEC 3500AG (2.18 w/bitsetting) on IDE 1
1 Aopen 1648/AAP on IDE 2


This sometimes happens to me when my hard drive is nearly full and I run imgtool classic; if your drive is nearly full or heavily fragmented ahead of time, it’s unavoidable. Once I had an .iso in over 10,000 fragments!:eek:

I’d say defraging is only ‘necessary’ when you are burning at high speeds and/or have a relatively slow hard drive. It varies from system to system on just how much fragmentation is needed to cause a buffer underrun at various burning speeds.

If your defrag program takes too long, try googling ‘contig’ or ‘contig.exe’. It’s a great little command line program that uses the built in NT-kernel based defrag utility to defrag a single file. Works faster than anything else I’ve tried and works even when there isn’t enough space for a full disc defrag.


I always prefer burning from ISO, it is less stress on the PC, both CPU and hard drives so it is better for slower PCs that might slow down while the burning is taking place and cause the burn-proof to be activated. The one ISO file, even when fragmented a lot, is more “together” than 10-20 different files in a directory so there is good chance you get “hit” in the disk’s cache. Also have the advantage of final testing the ISO before the actual burn, why waste even 20 cents media?

Anyway, I do not have utility to check fragmentation of a file, but I have noticed that if you generate ISO with ImgTools Classic, it makes a lot of hard drive grinding and actually takes longer than my prefered way of making ISO: DVD Shrink. The DVD Shrink is 1-2 minutes faster, even with the 1 minute pre-loading in the Open Files mode, and the hard drive is relatively quiet. I do not know if the ISO will be more of less fragmented, you need to check.

To best of my limited knowledge, no ISO making tool will try and pre-allocated the target ISO in one big lump of 4.7GB, hence, there is a need for multiple writes. So, my bet is that ImgTools is writing about 200 times smaller chunks, and DVD Shrink is writing fewer number of bigger chunks.