On Fri, 13 Jan 2006 19:41:14 -0700 (MST), Austin Hook <[EMAIL PROTECTED]> wrote:
>After buying a used Dell 2850 PowerEdge rack mount server I tried to >install 3.8 but I found that the CDROM seemed to be giving me bad data. >The tar/unzip process during install seemed to have trouble with larger >data files, complaining something about having to search for header data >after apparently getting some junk. What was curious is that the read >itself didnt seem to report any errors, only the tar extract process >seemed to be complaining. > >So I installed over my network by ftp, using the same CD #1 from the 3.8 >set. All went well. > >Afterwards I decided to do the following (typescript follows): > >Script started on Fri Jan 13 10:30:15 2006 ># # Previously I did a mkdir /cdrom ># mount -t cd9660 -r /dev/cd0a /cdrom ># cp /cdrom/3.8/i386/base38.tgz . ># diff /cdrom/3.8/i386/base38.tgz base38.tgz >Binary files /cdrom/3.8/i386/base38.tgz and base38.tgz differ ># exit > >Script done on Fri Jan 13 10:32:16 2006 > >In other words the file I got on hard drive after copying from the CDROM >was not the same as the file on the CDROM, and yet no read errors were >reported to me. > >However, if I do this on another machine -- the one where I mounted the >CDROM to do the across-net install, the two files do not differ. > >In all cases, on any machine or CDROM, I get the same length of file for >base38.tgz: 36790935. However a md5 checksum done either directly on the >Dell 2850 or on the copy I attempted to make, shows a different checksum, >whereas on other machines the checksums are the same for originals >directly computed off the cdrom or the copy I make to hard drive -- and >the those good checksums are different from both the original and the copy >I access on the Dell. I presume copies to the Dell, over the net are >fine. So it's just the process of reading from the CDROM on the Dell that >is happy to give bad data without saying so. > >Am I missing something? > >Austin Hi Austin, It seems Nick already beat me to the "Someone sold you a bad CD" joke but there are a couple other things worth checking besides the bad drive stuff Nick mentioned. The first is the CDROM cable you using and how it's routed in the box. Lower quality cables (lower gauge wires) are more susceptible to electrical noise from other sources. When ever I see something like what you described, I always run memory tests. Failed (or failing) RAM can and will do wicked and inconsistent things to file transfers of all types (including over the network). If your problem is actually RAM, what may have seemed like a successful install over the network, may actually be corrupted in a non-obvious way. Hope this helps, JCR
