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Emulate Target Disk Mode PowerMac G4 PCI

jamie marchant

jamie marchant

6502
Anway to emulate "Target Disk Mode" in Mac OS 9. This is for my G4 PCI which lacks such a feature in its firmware. 

If not possible, any way of doing this with a PC? I want to install a second OS on my Mac Mini G4(on a separate drive) but don't want to buy a firewire enclosure.

 
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The G4 PCI, you mean the one that was based on the B&W/Yikes! board? That one has a funny FireWire output, IIRC, that doesn't support the feature.

This is all going by memory, but Beige G3 Macs supported SCSI Target Disk Mode, and AGP G4 Macs supported FireWire Target Disk Mode.

I'm not entirely sure I follow what you're trying to do, as the FireWire enclosure + Target Disk Mode on the Mac Mini G4 is entirely feasible and not hard to get up and running. If you don't want the enclosure, I'm not quite sure how to do this with a Yikes!.

 
So I want to install a second OS on my Mac Mini G4 but I don't want to repartition the 40 GB drive inside it. It will not boot off of USB and I don't want to buy a FireWire enclosure, they are expensive cause FireWire is now a outdated technology.  

I have a couple of ideas though: 

  • Get the Mac Mini G4 to boot off of USB, I've looked into this but it's not easy. 
  • Get the Mac Mini to boot off another computer via Target Disk Mode
You are correct my PowerMac G4 Yikes does not have Target Disk Mode. There are still a couple of ideas: 

  • I have a Pentium 4(yes a PC) with a Firewire 400 PCI card in it. If I had some sort of server, maybe I could emulate "Target Disk Mode"
  • Maybe there is a way I can emulate this on Mac OS 9
  • Some sort of simple firmware "hack" to enable Target Disk Mode on the PowerMac G4 Yikes? 

 
I had a link to a BYO enclosure kit that was selling on eBay for less than $10 earlier but that sold out fast. All told, if you know what products to search for and they're not called out on eBay as a FireWire enclosure (L@@K Steve Jobs etc etc), they tend to sell for peanuts.

The thing about repartitioning is that you can do it in a non destructive way with Disk Utility on the Mac OS X Leopard installer DVD. As long as you have a backup handy, you can squeeze in a second partition that's 4 GB or less and easily destroyed when you don't need it. Tiger didn't have the nondestructive partitioning capability.

 
... so what you want to do is use the Yikes *as* a semi-permanent Firewire enclosure for *running* the OS on your Mini? That doesn't really sound like a fantastic idea even if it did work.

It does appear to be technically possible to create the equivalent of a "target disk mode" on a Linux host using the "spb-target" functionality of the Linux iscsi target infrastructure:

https://ieee1394.wiki.kernel.org/index.php/Sbp-target

Another link showing such an export mounted on a Mac:

http://www.studioteabag.com/science/sbp-target/

This is... sort of cool and I think I'd like to try it sometime. But it doesn't seem like a particularly practical thing to do for day-to-day use.

 
That looks like it would do what I want, thanks. I would be installing a second drive in my computer so it would still be usable as a normal computer. The only problems I see are: maybe speed and it would take more power than an enclosure. 

 
If you plan to run this for any length of time wouldn't it ultimately be more useful to install a bigger drive in your Mini? I realize that's a PITA to do, but ultimately it seems like the correct solution to the problem. If you want to keep whatever's on your existing drive you could either:

1: Put the Mini into a target disk mode and image its internal drive for later recovery using the Yikes, or:

2: Once you've swapped drives, partitioned, and have a booting OS on it you could use one of those USB-to-PATA dongles to access the old drive and copy your stuff off it.

 
I don't know whether I want to do this for any length of time or not, at the moment, it's just an experiment. 

Even if I wanted too I don't have any small IDE hard drives and I am not confident enough with hardware to do that procedure. I only take apart laptops if I don't care about them. 

 
Let us know how it goes, then. I am actually intrigued by the possibilities of using/abusing the Linux iSCSI infrastructure this way. Note that you don't even need to dedicate a drive to it, the target can be a file. It might be an... interesting? way of compiling a library of different firewire-bootable OS installs that you can access at will with an appropriate Mac. Heck, I can actually see it potentially opening up the possibility of creating OS disks with QEMU; in principle it seems you could share a RAW-format QEMU disk image this way. Or maybe even share raw .isos?

 
Sounds way cool, but way work for a simple OS install. One of those little bare dongle/power adapter USB to IDE/SATA adapters should be in everyone's kit, the MOLEX power adapter alone comes in very handy at times for mucking about in the 68K toys doing temporary hookups. A USB/FW enclosure is right up there too in my book as well. Gotta have a little bag of tricks to pull out on occasion.

 
Actually it looks like a trivially lightweight solution to me, if you happen to already have a Linux machine with a FireWire port.

I happen to have a Linux-running Thinkpad T61 that has IEEE 1394, if I can without too much hassle find the necessary cabling to hook it to a PowerBook I'm going to try it.

 
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So... I wasn't able to find my 6-to-4 pin FW cable. (It was supposed to be in the ancient camcorder's bag, but, nope.) But I *did* find a FW800 cable, and, coincidentally enough, also discovered that the last 1.5ghz Powerbook G4 I had in a box in the garage has a dead hard disk. (RIP) In  the process of updating the Linux install on my Mac Pro to a more recent version that includes the Firewire target module (I didn't realize it had been *that* long since I'd used it.), my goal is to see if I can boot a Tiger .iso shared as an iSCSI target. Just for laffs.

 
Trash80toHP_Mini said:
That'd be a 10lb. sledge and a broken furniture frame under that loose upholstery. [:P] 
Click to expand...
I think at this point I'm not even going to ask.

In any case, the reason I think this is interesting, particularly if you *do* happen to have a laptop with a firewire port, is if it really works it potentially would make it possible to lug around a complete library of "rescue disks" you can use to start up any firewire bootable Mac in one little package... which at the same time can also remain usable as a computer. (Opening up possibilities like, say, using the ethernet port on the same laptop to share a wireless Internet connection with the same Mac you're rescue booting.)

Obviously this is stupid overkill if all you want is a "permanent" firewire enclosure. If that's the point you're harping on I don't think anyone feels differently.

 
Not harping, just having a little fun with the old saw about "if all you have is a hammer" on a weight class/misapplication of the many flavors of hammers theme. You're absolutely right about your project and you'll notice I did say it was way cool right up front. Thanks for fleshing the notion out some more. Just because I can is a plenty good enough reason for me.

Pops played around with upholstered furniture making and repairs. I was into the fine woodworking end of things, but he gave me a proper tack hammer, bronze with a rare earth magnet. [:)]

 
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