On Sunday 28 December 2008 11:18:53 Phil M Perry wrote: > Adam wrote: > > So Ubuntu's installed, but I don't understand /why/ it worked. How > > would the copy I burned be any different from the one that Ubuntu > > pressed? > > Well, that's strange. All I can guess is that it's a marginal original > copy (the > pressed disc) or a marginal drive. Normally, a /pressed/ (stamped) disc is > read quite reliably. CD-Rs and CD-RWs are usually less reliable (do you > know for sure whether the Ubuntu distribution was on a CD-ROM (pressed) > or CD-R(W) (burned)? The higher the speed, the thinner the dye layer, and > the faster the write (but less reliable the read). Compared to the Windows > settings, Ubuntu must be a tad more aggressive in its read settings, and > failing on a marginal disc that Windows could read. I wonder if there's any > way to set Ubuntu's read to a bit slower without a recompile?
There are a whole lot of on-the-fly settable parameters in /proc/sys and /sys and to be honest I don't even know how much of this particular area is tunable and how much of it is hard coded on the CD drive firmware. However, at least some of this is tweakable, because you can choose the scheduler used to read an IDE cdrom for instance, how much read-ahead to do in KB, and a bunch of other particular I/O scheduler settings that I don't pretend to understand. So basically the answer is yes, there's a way to set certain things related to this without recompiling, but the interface is meant for experts and I haven't yet found a document that succinctly explains all of the settings for mere mortals. There's also a command 'ionice' that allows setting several I/O priority levels on a per-process basis. I just discovered its existence by reading Linux/Documentation/block/ioprio.txt from the vanilla Linux sources. > A way that would work on a boot-up install disc? Assuming a /proc/sys or /sys/block setting fixes this it could be done from a command line or GUI "run command" in the Unbuntu LiveCD before running the installation process. -- Chris -- Chris Knadle [email protected] _______________________________________________ Mid-Hudson Valley Linux Users Group http://mhvlug.org http://mhvlug.org/cgi-bin/mailman/listinfo/mhvlug Upcoming Meetings (6pm - 8pm) MHVLS Auditorium Dec 3 - Lightning Talks & Swap Session
