Jan 072007
 

I recently replaced an elderly SGI Octane2 workstation which had 2 CPUs (400MHz MIPS-based), 1.5Gbytes of memory, and 3 elderly SCSI disks with a nice new Sun Ultra40 … 2 AMD Opteron 248s, 2Gbytes memory, and 2 mirrored SATA drives. It is interesting to compare the difference between an old-fashioned workstation originally designed in the middle to late 1990s with a 21st century PC. Not that I’m going to produce hard numbers from useful benchmarks … that is just too much work, and in some ways it is the feel of the differences that are important.

Of course this is not really a fair comparison. Whilst the SGI Octane is now very elderly and due to SGI managerial incompetence has not kept pace with PC performance as it should have done, it is after all a machine that originally cost 10-20 times the cost of the PC I am comparing it to. In car terms, I’m comparing a 20-year old Mercedes with a new and cheap Ford. I should point out that much of the software I am using is very much the same on both machines … the Enlightenment window manager, Sylpheed Claws as the mail client, Firefox as the browser, LyX as the word processor, and a text terminal for much of the remainder.

The PC is considerably quicker than the SGI of course. The graphic user interface is a good deal snappier, and most of the applications offer very welcome improvements in performance. With the exception of GIMP however, none of this performance increase is really essential; my old SGI ran pretty much everything my PC does, fast enough to get the job done. GIMP performance is the reason I upgraded, and here the difference is quite dramatic … filters that previous required patience now run almost instantly; when you are repeatedly trying things out in GIMP on quite large images this performance increase makes some things feasible that simply were not before.

There is one area where the SGI does offer some advantage over the PC; something I was expecting. The PCs disks are overall somewhat faster the the disks in the SGI (and of course I don’t have to pay to mirror my disks!), but the SGI tends to work more smoothly under high load. I’ve noticed before with the ‘low end’ on disks in PCs, that if you start to drive your disks very hard, the computer will sometimes stutter. Essentially the SGI was slower, but smoother under high disk load than the PC.

If was not for the need to run GIMP extensively (and the appeal of more standard add-on hardware like USB hard disks), there is no reason why I could not continue with the SGI. The tendency we have in the computing arena of replacing computers every few years is not a healthy one.

Oct 152006
 

First of my real blog entries on IT … or computing, or anything related to technology really.

I work in computing so it is hardly surprising that I have a few opinions on it (or IT), but I’ll try to restrain myself from getting too technical.

Today’s entry is about how having too much knowledge can actually slow you down when trying to resolve an issue. You see, I had a bit of a problem on my SGI workstation when trying to run GIMP or Ufraw (both of which are essential to doing any kind of photographic work). When trying to use either, the application would crash with a little error message saying that I had run out of memory. This was kind of hard to believe as I have 1.5Gbytes of memory in the SGI, and I was not processing any unusually large files.

However I had recently upgraded the software on my workstation, so my instinct was to blame that. The error message indicated that the problem was with a component called glib so I spent hours recompiling that component using multiple different versions so see if I could eliminate the problem. No luck. I even read the source code to the relevant part of glib and tried a couple of experiments to see what was wrong that way. No luck.

After all that time, I spent some more productive time hunting in the appropriate place to find out my problem was probably related to an IRIXism … rqs which was not written to take into account just how many shared libraries applications based on GNOME use these days. A quick fix using rqsall and all was fixed.

Ignoring all the technical details, my knowledge of how Unix works had led me down the wrong path because all the symptoms seemed to indicate an application problem where the real problem was with the operating system. A quick hunt where all the experts hang out showed where the problem was. If I had looked to begin with, I would have saved myself a great deal of time!

However hunting down the wrong path was useful … it helped me practice some skills which need occasional use.

Oh! Don’t assume that my experience is common with those who use Linux. If you stick to a stable distribution and don’t mess too much you will not see this sort of thing.