" Western Digital WD4000KD 400GB
Apple iMac Intel CPU, OS X 10.4.x
I thought I would send a note that after taking the time to disassemble my new iMac this hard drive is not compatable. I tried to use this drive in my 1.83ghz core duo Intel iMac and I tried every jumper listed here:
http://support.wdc.com/images/kb/sata.gif

Default 1: Did not mount
Default 2 (SSC): Did not mount
(reader FYI - as mentioned in the past here, the onboard G5 Mac's SATA reportedly is not compatible with SSC (Spread Spectrum Clocking) enabled drives, but that may not be true of Intel based Macs.-Mike)
SSC, PM2: Mounted, formated, OSX install DVD said I could not install OSX on the drive
OPT1: Same as SSC, PM2
OPT2: Did not mount

This is really too bad that this drive does not work. Any suggestions? I took many pictures of my take apart and will put them on a site soon. I will send the link when they are up.
-John W. "

At first this reminded me of the WD4000KD Onboard G5 SATA Problems, but Richard also sent a reminder that the Intel Macs require a GUID Partition Table (GPT) for bootable drives.
I searched and found an Apple developer doc with notes on this:

" Disk Partitions
The standard disk partition format on an Intel-based Macintosh computer differs from the disk partition format of a PowerPC-based Macintosh computer. If your application depends on the partitioning details of the disk, it may not behave as expected.Partitioning details can affect tools that examine the hard disk at a low level.

By default, internal hard drives on Intel-based Macintosh computers use the GUID Partition Table (GPT) scheme and external drives use the Apple Partition Map (APM) partition scheme. To create an external USB or FireWire disk that can boot an Intel-based Macintosh computer, select the GPT disk partition scheme option using Apple Disk Utility. Starting up an Intel-based Macintosh using an APM disk is not supported. "

Update - See Friday's news for John's Latest notes on WD 4000KD problems in Intel CPU iMac - drive format was not the issue he said and a Maxtor 300GB drive worked fine.

"Here is an email I sent to an alias we have at work which discusses everything I accomplished in using it

I've just spent a Saturday afternoon learning about Xgrid, and I thought I would share the results. Part of my objective was just to debunk the myth that you can just turn Xgrid on and suddenly it's like you have more CPU's in your mac. The other part of my objective was to figure out exactly what it takes to make use of Xgrid. Apple's marketing talks a lot about how easy it is to set up Xgrid, and very little about what you have to do to then use it.

Myths debunked:
So, the myth is certainly debunked. If you know anything about parallel computing, then you know that a multi-cpu computer can't figure out how to parallelize a task. It can only be given tasks that are known to be independant, and then run them in parallel. What I had hoped was that Xgrid uses the same logic that is in a multi-CPU OS X box to distribute processes to multiple computers. I figured even this was too much to hope for, and it was.

In short, all Xgrid does is take discrete tasks that you give it, and farm them out to multiple machines. The onus is completely on the user to break up a bunch of work (a "job") into separate tasks that can be accomplished in parallel. You can also simply give it totally unrelated jobs, and they will be distributed. Xgrid has no ability to break up a single piece of work you give it into parallel tasks on it's own, and it certainly doesn't sit in the background and farm out processes over the network without your input.

Another important detail: the tasks that you give Xgrid are command line tasks. For example, you can not use Xgrid to get iDVD to render a DVD faster - not even if there are multiple separate video assets that need to be encoded. It is possible for a GUI app to take advantage of Xgrid natively. There is an API. I do not know in that case if the tasks you give it have to still be command line, but my guess is they probably do; since there is no interaction between the controller and the agent until the task is complete, there would hardly be any value to the task having a GUI. iDVD could theoretically be written to break up it's work into multiple tasks and submit them to Xgrid to be farmed out, but of course it has not been so written.

Making use of Xgrid:
This simplest thing you can do with Xgrid is just give it a command line to execute. If there are files and directories involved though, this will not work b/c Xgrid needs to know what they are to distribute them to the agent that gets the task.

The second simplest thing you can do is give it a command and specify files or directories to go with it, so they will be copied to the agent for the work.

In both of the above cases, you get a single job with a single task in it. If you submit multiple jobs, they will be distributed in parallel, but a single job with a single task can't be broken up.

The more interesting way to use Xgrid is with a batch file. These are .plist filex (XML underneath) which you can edit with Property List Editor. A single batch file can specify many jobs, and each job can specify many tasks. Each task can specify a command, arguments, input files, output files, and lots of other things. You can also specify a task "template" with a lot of parameters, and then refer to that template in several tasks. In this case, each task need only specify additional or different parameters from what is specified in the template. Incidentally, you can also describe dependancies in a batch file, such as if a certain task can't be executed until another one completes.

I made a little batch file with 8 tasks in it, all of which were "sleep" with varying numbers of seconds. In other words, I was able to get a grid comprised of my mini and my PB to do nothing approximately twice as fast as either of them can do that on their own. It was pretty fun to watch the Xgrid Admin application heat up both processors, farm out the tasks to them, and then watch the progress bar move forward as each agent completed one of the tasks.

Basically what it boils down to is that if you have work to do that is in a state where you could manually go to a bunch of different macs and use the CLI to do parts of it in parallel, then Xgrid is a great way to make that really easy to do, although building the batch file for a new user would probably take as much time as farming out the tasks manually. But if you have to do similar work repeatedly, and the specs only vary slightly, then your batch file might be quite re-usable.

My primary resources for this research were:
The xgrid cli command man page - man xgrid, or http://tinyurl.com/9r2qb
The Xgrid administrator manual
The macosxhints hint on using Xgrid w/out OS X Sever
Apple's Xgrid Technology Brief
-Avram "

The next day a reader replied to Avram's comments:

" XGrid comments:
I thought it would only be fair to point out that XGrid does exactly what it promises to do. His expectations for it to act like an automatic extension of processors was just wrong. That's not what distributed computing is about.
He confused a super-computer cluster with XGrid distributed computing. It takes incredibly fast connections between machines to make the overhead of passing low level code between machines worthwhile. It has to be distinct, independent chunks of data to be processed for something like XGrid to be valuable. It is more like SETI at Home than a super computer set up.
-Mark S. "

• Walt Disney Buying Pixar Vaulting Steve Jobs Into Prominent Disney Role
• 10.4.4 Dock Outbound Net traffic
• Podcast Maker 1.1.6
• RAW Developer 1.4.4 (RAW image conversion application)
• Portable Firefox 1.5r2.0 (Firefox browser pkg for flash drives)
• Synergy 2.4 released (iTunes accessory updated for Intel CPU Macs)
• Yojimbo information organizer from Bare Bones Software
• Skype 2 does Video
• new Adobe software turns 3D images into PDFs
• Tax Software reviewed

DVD+R/RW + DVD-R/RW Drives:
• IDE Liteon SHW-1635S in B&W G3 (OS X 10.4)
  (Illustrated CD drive install guide here covers B&W G3, Beige G3 MT and G4 towers up to the Digital Audio Model)
• IDE Pioneer DVR-K05 in PowerBook G4 (OS X 10.4)
  (noted drive reported as slave and not bootable from C key but was from Option key. Also see Cable mods to force master mode w/PowerBook G4 optical drives.)
  
  Hard Drives:
• IDE (SerialATA onboard) Western Digital WD4000KD 400GB in iMac Intel CPU (OS X 10.4)
  (problems noted - see also page here on WD400GB/16MB cache Onboard G5 SATA Problems.)

You can find full owner reports (latest shown first) by searching the database by drive/brand/interface/mac models (the latest reports are shown first in searches). For guides to installing CD/CDRW/DVD drives or Hard drives in many mac models, see the IDE Articles page. The Firewire articles page also has guides on case kits, installing drives, etc.
If you've added a IDE, SCSI, Firewire or USB hard drive, CDRW, tape drive, etc. make sure you add a report to the database. (If you post an updated entry - make sure you use the same name, etc. as you did before so I can find your past entry. Thanks.)
(Incomplete entries are deleted. Do not post questions in the database, it's for drive reports not questions on what drive to buy - for that try searching the database for reports from owners of your mac model on the drive type/brand/interface, etc. you're interested in.)

• Giga Designs Dual G4/1.8GHz (7447A) in (Digital Audio) G4/AGP (rated 10)
• Wegener Media G4/500 in PowerBook G3 wallstreet2 (rated 1)
  (Listed under "Other Brand" - mentioned upgrade module failed quickly, logic board damage, problems getting replacement.)
  
  (Full reviews of G4 and G3 upgrades compared to stock CPUs, including real world apps/game tests, install info, etc. are linked at the CPU upgrades page. OC/CPU module articles are on the Systems page.)

(Warning - Overclocking may not be reliable and could lead to hardware failure or corrupted data.) You can find the full reports by searching the database selecting the indicated Mac model and upgrade card brand/type. If you've upgraded the CPU on your Mac, please post an entry in the database. Search the database for entries from most every upgradable Mac model *before* you buy. (Searchable by mac model/upgrade brand).