Re: [Staffslug] ISO Image dd To DVD+RW

Hi: Latest issue of Linux Format Mag gives you a DVD ISO Image for FreeBSD v8.0, which I happen to be interested in. I was also looking for an interesting use for my DVD+RW disks. I read somewhere you could "dd" straight from an ISO Image file to DVD+RW, though I couldn't remember where. Previously I thought you could put an Ext2 Filesystem on DVD+RW, which turned out to be wrong. It worked the first time I tried, but not the second. But this experiment with "dd" worked, though I'm still unsure about how to use some of the options properly. Basically (under Linux) I put: dd if=FreeBSD-8.iso of=/dev/sr1 ibs=512 obs=32768 conv=sync And my DVD+RW wrote okay, showing: 3986344+0 Records In 62286+1 Records Out Note that DVDs use 2048-byte Sectors like CDs, but they're handled in Error-Correcting Super-Blocks of 16. DVD+RW can write individual Sectors, but only by updating the entire Super-Block. My first attempt tried writing with a BlockSize of 2048, whereupon Drive /dev/sr1 sat there winding the disk back and forth, presumably writing every Super-Block 16 times over. With a total BlockSize of 32768 things went alot more smoothly. The 62286+1 Records Out are Super-Blocks with an extra one partially written. The original 3986344 Records were 512-byte Disk Blocks, which make a whole number of 2048-byte DVD Sectors, but not Super-Blocks. Then I wrote it back to a file so I could check the result using diff: dd if=/dev/sr1 of=CHECK.ISO bs=2048 count=996586 conv=notrunc Here it's okay to read the DVD as 2048-byte Sectors, because they're individually addressable. You need the count to stop the entire DVD getting imaged, all 4.7 GB, which happened the first time I tried. And of course it's the count of 2048-byte Sectors, which is 3986344/4. CHECK.ISO was identical to the original Iso Image, and I was able to use the DVD+RW to install FreeBSD v8.0. Which left me with the same Xorg Configuration problems as FreeBSD v7.2, but that's another story... Faictz Ce Que Vouldras: Frank Mitchell _______________________________________________ Staffslug mailing list Staffslug(a)staffslug.org.uk http://lists.staffslug.org.uk/mailman/listinfo/staffslug