Dan Poirot and Robin Ristow

A Tale of Two Utilities...

It's OK, we will leave Dickens out of this one...

A prospect asks if Wind River Platform for Network Equipment - Linux Edition is going to work on his CentOS 4.4 system. Officially we support RHEL WS 3 U5, RHEL WS 4 U2 and SUSE 9.3 and 10. ...so let's see!

The CentOS site claims "CentOS 4.4 is an Enterprise-class Linux Distribution derived from sources freely provided to the public by a prominent North American Enterprise Linux vendor.  CentOS conforms fully with the upstream vendors redistribution policy and aims to be 100% binary compatible."

Sounds very encouraging. I am off to get CentOS CD images. No great big DVD ISO to be found so I am faced with downloading four separate images. This could take forever with the web browser and leave me with partially downloaded images if any of the download fails. Worse yet, aggrivating Internet Explorer only wants to download up to three files at a time.

Enter GetRight Download Manager. Back in the day, download managers were all the rage when all we had was dialup. GetRight has done a fine job of keeping up with technology. I found that it could easily manage downloading all four files, split each download up to five times for parallel downloads and even search for the fastest download site FOR EACH FILE on it's own! So cool. It soaked my cable modem and I had trouble free downloads of the images in no time!

On to the installation... CentOS looks oh so much like RedHat WS 4. No problems there. I am installing in a partition on my daughter's game machine. This is the same machine I used to play with HDTune and the RAID controller last year.

I fat-fingered the install. At one point the installer is setting up the partition table. I wasn't paying attention and selected the option to delete the partition table on /dev/hde. This worked out to be just one of the drives in my RAID. YIKES!

I am only as smart as GOOGLE... I enter "recover partition table" and get lots of help. The first few commercial tools, http://www.partition-recovery.com/ and Partition Table Doctor offer demos that show they can find my partition table! Hurray!

A little further along I find TestDisk 6.5:
It was primarily designed to help recover lost partitions and/or make non-booting disks bootable again when these symptoms are caused by faulty software, certain types of viruses or human error (such as accidentally deleting your Partition Table).

Sounds like just the ticket! I downloaded the Windows version, ran the program, accepted all the defaults and a reboot later had my RAID back! Slick.

The rest of the CentOS evaluation was much less traumatic. Everything just worked. They are using the same 2.6.9 kernel and RPMs as RHEL WS 4 so that really wasn't much of a surprise.

Why is my PC so slow?

Howdy all. Why does it seem that my PC is so slow?

Back when I was a Wind River customer (yeah, yeah, dinosaurs walked the Earth and the planet's crust was still cooling) VxWorks 5.1 developers used the command line in a 'shadow' directory of the product distribution. Editing was done with 'vi' and BSPs and apps were built with 'make'. We lived in the era of 'burn and churn.'

All of this happened on big (for the time) shared Sun 3 boxes. PC's were a novelty -- the exclusive toy of the accountants and finance people (who didn't have any real work to get done.

These days the masses are blessed (or is it burdened?) with more computing power than they can figure out how to use. This has been a boon to distributed projects like SETI@home and Folding@home. Who would have though that there would be teraflops of performance in a video card?

But developers are (always) different! With the distribution of full OS and network stack source in the VxWorks 6 era, customers are building more of our product. At the same time apps are bursting in size. There never seems to be enough performance.

So why does compiling this take so long? I have a fast CPU and lots of RAM - what could it be?

HD Tune to the rescue! With a tiny bit of attention to detail and the addition of a $15 PCI RAID card, I now have a disk I/O screamer!

I started out in PIO mode because I had a problem with the chip set driver. Download pio0.JPG

I then went from UDMA2 Download udma2_40pin.JPG

to UDMA5 by simply swapping the 40-pin cable for a high quality 80-pin unit. Download udma5_80pin.JPG

All the best goodness comes from adding a $15 RAID card to the pair of drives I already had! Download SiL680a_RAID.JPG

This is really only a solution for local copies of files which are maintained in a reliable configuration management system!

Keep in mind with increasingly larger capacity disk drives (driven by serial ATA drives), the risk of drive failure is increasing. Additionally, bit error correction technologies have not kept up with rapidly rising drive capacities, resulting in higher risks of encountering media errors. In the case where a failed drive is not replaced in a RAID 0+1 configuration, a single uncorrectable media error occurring on the mirrored hard drive would result in data loss!

Given these increasing risks with RAID 0+1, many business and mission critical enterprise environments are beginning to evaluate more fault tolerant RAID setups that add underlying disk parity. Among the most promising are hybrid approaches such as RAID 0+1+5 (mirroring above single parity) or RAID 0+1+6 (mirroring above dual parity).