Monday, April 7, 2008

The long-awaited SCSI Odyssey

What began as an amalgam of intention, performance lust and opportunity culminated this weekend in an electronic journey of mini-epic proportions.

To refresh: The conundrum so far was how to best utilize a pair of 74 gigabyte 10k SCSI drives. My former setup used a 160 and a 320 gig sata drive as system and storage respectively. Even with both drives at a full clip the capacity just wasn't there.

So I decided to favor speed instead.

Now I dare not try to educate anyone in the ways of SCSI and there are plenty of good damn reasons why this technology never took off. Allow me to briefly enumerate them here:

1) Cost - Going by the retail road would have made this project prohibitively expensive. The drives, card and cable would have been unaffordable. Even at newegg comparable equipment would total out at $400 for 1 cable ($35) 1 card ($155) and two drives ($210) At this rate the actual project would have cost far more than I would have been willing to spend. I make it a habit never to spend more on a single component than the rest of the build combined. Even the comparably cheap alternatives that I secured make duplication an ill-advised prospect.

2) Complexity - The card I ended up getting has its own BIOS which is neat. However there was already an array configured and I had to tinker with it to kill that. Once done it was pretty easy to set up the RAID 0 array that I wanted. The drivers proved difficult. More on that later.

3) The Bottom Line - Storage is cheap and marginal gains for hundreds of dollars don't make sense. The whole point of this adventure was to nudge along the slowest component for a few modest performance gains and to learn more about SCSI in the process. While I did learn about it the amount of money it would have required otherwise, the amount of time I spent reading up and searching for components that would mesh well and the pure frustration of the setup all sucked quite a bit of life out of me.

Here's how it happened, starting from after Zaps came to life and demolished every crash test I could devise. I woke up early on Saturday, watched Battlestar (hey it'd been a year) and then got to work. I hauled old Rorschach out of my desk and disconnected all (kb, mouse, vga, dvi, printer usb, backup usb, sound x3, ethernet and power) 11 cables. I haven't gutted the main system in months so there was some requisite dust removal to be done.

Opening the case revealed, once again, what I consider the only true flaw in my PC case.


Notice anything ugly right off the bat? At the bottom of the case there is a HUGE honkin' video card that extends to within just a few inches of the front cages (where the hard drives live) A myriad of cables form an ugly clot right at that spot because of the bottleneck. I have developed great respect for single slot video cards and intend to get one next time around.

Here's Beebe interior for comparison:

Anyway. So when I began there were three drives installed. 160 Sata, 320 Sata and a 300 IDE drive. In case anyone cares that's .78 terabytes total. However this exercise pays homage to speed not storage so I ganked the IDE drive to make room for SCSI 1 and SCSI 2. This was touchy because of the bottleneck and the certain reluctance to remote everything out of the case for a few new parts. (The two drives on top are the SCSI drives, they are noticeably different in weight and heft than their SATA brethren.)

I struggled, I won. Connecting the drives was easy. I had to remove a capture card (mostly just a space filler) to make room for the raid card. This dropped in with no problems.

I turned her on and was immediately able to access the Raid BIOS. As I said before I had to kill off the old settings, demolish the mirrored array that was set up and create a new RAID 0 array. All told this took about 10 minutes. So far so good.

Not like Zaps with the fucking busted cable!! Click on the picture to see why the cable didn't work.

I kept my fingers crossed that the embedded drivers in XP would allow me to install without need for a floppy. Just to be clear I haven't willingly used a floppy since I was a freshman in college way back when. And with good reason!!!! How pathetic is this: In order to scrounge up a useable floppy I had to dig around and actually dug up one of my freshman papers. I'll post it later for a laugh.

Anyway, I rescued the disk and added the data cable for my unused and untested floppy drive when I hit a wall. There was no power! Worse as I examined my various modular power cables I could not find a mini-molex connector to save my life.

Drat! Needless to say I found a way around this hurdle by pulling the mini-molex out of Beebe, across into space and into the main case of Rorschach. I know its pretty ghetto but we does what we must.

So diskette in hand I was able to do my fresh install of XP with minimal difficulty. I had to restart once because I didn't set the boot order correctly in the BIOS but once done it was a snap. After that the total time between selecting the partition to install on and the first boot was only about 14 minutes.

Success! I was thrilled. Of course since I had chipped away at this on and off and had to pick up Alex I began the data transfer from the former system drive and went to bed. Sunday came and I was able to reinstall all the drivers, recover all my pics and music and generally return things to a state of normalcy once again.

And then. Benchmarking!!

So before I did the switchover I ran few HD benchmarks on HD tune for reference.

However I am starting to be a little skeptical about the first test because I have not been able to duplicate the access time. Anyway. Those are the benchies from the pre-SCSI setup.

Here are the SCSI ones.

Here's the more consistent 160 gig sata benchmark.
Basically, the Sata drive claims to have a much higher burst rate and and average data transfer rate of 60-70 mb/sec. The SCSI drive had a higher average minimum, maximum and average data transfer rate though the burst rate remained far below. Out of 6 trials only once did the SCSI burst rate break 100mb/sec.

So objectively, to use diablo terms, the SATA drive is lightning damage (IE a wide scope that ranges from really high to really low) and the SCSI setup is a more solid fire damage (average is higher but so are both ends of the spectrum)

Subjectively the system feels snappier and the install FLEW by compared to the original setup. While most of my work relates to online stuff I have noticed that transferring big chunks of data around on the hard drive seems to occur significantly faster. The biggest area of improvement is the virtual PC performance. Shutting down and starting these up goes by in about a third of the time (subjectively, I forgot to stopwatch it beforehand)

Closing thoughts: There is something to be said about character building exercises and this was one of those things. Quote me on that: SCSI builds character.

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