"Apple ROM" Hard Disks

[Phipli]

So, I'm confused. When I was a kid, we used to talk about Apple ROM'd Hard Disks and CD Drives... and you saw drives with the little red apple logo on them, and told each other "oh, that one has the Apple ROM"... but with time, we realised it was nonsense, and infact Apple just maintained a whitelist in the CD driver / disk formatting tools, meaning that if you got an OEM (i.e. non-apple) version of the same Matsushita, Seagate or Quantum drive, it worked exactly the same.

What is confusing me is I'm still seeing people refer to Apple ROM'd drives, for example @volvo242gt here :

Had a 230MB Quantum that would make a short "skrrrk" sound, then sit there, spinning away. Turned out that the board had become fried. Replaced it with another board, and the drive works again. Now is an Apple ROM'ed 230MB, too.

Is there something about the controller board that he is mentioning that I've overlooked? What extra does it do?

I'm absolutely certain that all the apple formatting tools do is check the disk manufacturer and part number against a whitelist... because the whitelist is just a list of resources inside Drive Setup and the older SCSI formatting tool.

I am also certain that "non-apple" drives that are on that list work just fine, because I bought a bunch of Segates that fit one of the more broad Segate wildcard disk series in said white list.

I'm once again doubting what I thought I knew for certain. Because I've seen it mentioned multiple times without being challenged in the recent past. What are your thoughts @volvo242gt? What differences have you noticed? Can they be explained in another way? What have I missed!

 

[mikes-macs]

I've always thought the same. For years I always used Apple ROM'd drives only on vintage Macs. However, there may be diagnostic routines in the software on the drive that are incompatible. Aside from being able to format and install drivers, Drive utilities also run diagnostics that are built-in to the SCSI drive. Onward to PPC Macs SCSI or ATA, Apple ROM'd drives handle even more tasks under the hood than before especially in servers.
We all know how thorough Apple was in Verifying routines...

 

[CircuitBored]

There are definitely custom firmwares on certain "Apple" hard drives but I don't think there were really any extra features or components until the mid-generation Intel models (2012-2017). For example, if you pull the original HDD from a 2015 iMac and replace it with something generic then the HDD fan will go beserk. This is because the original drive has a Mac-specific temperature sensor that the HDD fan corresponds to. You can/could buy adapters that add this functionality back to third-party disks or you can just slow the fan using software. Those "custom" Apple disks work fine in generic x86 systems and just act like you'd expect a normal hard drive to.

Going further back you just have Apple-branded disks that feature on Apple's whitelist. I've never heard of these drives having any special features beyond the name. Once the G4 era arrived most Apple computers would accept any extant IDE hard drive without any fuss.

 

[dougg3]

You are correct that Drive Setup/Apple HD SC Setup keep a list of models they know about, but there's more to it than that.

Apple HD SC Setup checks for mode sense page 0x30 and looks for an exact response of "APPLE COMPUTER, INC." while determining if it's a drive it can talk to. I'm pretty sure that Drive Setup does as well. I don't think that normal generic drives without an Apple ROM return the "APPLE COMPUTER, INC." in response to mode page 0x30.

Here's a link to the forum thread where I worked this out with the original creator of SCSI2SD (mmcmaster). I also verified that there is code in Apple HD SC Setup that indeed looks for this response.

 

[Phipli]

You are correct that Drive Setup/Apple HD SC Setup keep a list of models they know about, but there's more to it than that.

Apple HD SC Setup checks for mode sense page 0x30 and looks for an exact response of "APPLE COMPUTER, INC." while determining if it's a drive it can talk to. I'm pretty sure that Drive Setup does as well. I don't think that normal generic drives without an Apple ROM return the "APPLE COMPUTER, INC." in response to mode page 0x30.

Here's a link to the forum thread where I worked this out with the original creator of SCSI2SD (mmcmaster). I also verified that there is code in Apple HD SC Setup that indeed looks for this response.

Thank you. Interesting.

I'm wondering if they dropped that in later versions of Drive Setup?

One thing I have noticed is that if you already have the apple driver on a disk, the non-Apple disks are then recognised by the drive tools.

 

[NJRoadfan]

Pretty sure the only thing special about Apple ROMs on the SCSI drives are the vendor field being set to Apple as above. Otherwise they are bog standard drives.

As for the Intel era drives, its just Apple being Apple again. All SATA drives support reading the drive temperature via the SMART diagnostics.

 

[Forrest]

There was a hacked version of Apple Drive setup that worked with nearly all SCSI drives. Another option is FWB Hard Disk Toolkit that allowed booting from non-Apple drives. This was shipped with Umax Mac clones and probably other Mac clones on the System CD.

 

[dougg3]

Thank you. Interesting.

I'm wondering if they dropped that in later versions of Drive Setup?

One thing I have noticed is that if you already have the apple driver on a disk, the non-Apple disks are then recognised by the drive tools.

Ahh, the plot thickens. I should have looked a little deeper before commenting. I'm not sure about the Apple driver thing, but I think it is more complicated than I originally said. After you said that, it made me curious so I went back and looked at my disassembly of Apple HD SC Setup 7.3.5 from years and years ago. It looks like each drive model in the list has a flag that indicates whether it actually cares about the special Apple SCSI response or not. I didn't pick up on that when I originally examined the code.

So on some models, just being in the list is good enough. But other models expect the Apple SCSI response in addition to being in the table. And who knows how different Drive Setup's logic is...although I do see the APPLE COMPUTER, INC. string in one of Drive Setup's CODE resources so I'm sure it's looking at it in some way.

There's a chance I'm wrong here because I'm not in a 68k assembly mindset right now, but it looks like most drives in the list do care about seeing the Apple response, with the exception of the first 6: Seagate ST225N/ST250N, Rodime RO632, Quantum Q250/Q280, and Miniscribe M8425. It might be interesting to play with a SCSI2SD sometime to verify that.

 

[Phipli]

So on some models, just being in the list is good enough. But other models expect the Apple SCSI response in addition to being in the table. And who knows how different Drive Setup's logic is...although I do see the APPLE COMPUTER, INC. string in one of Drive Setup's CODE resources so I'm sure it's looking at it in some way.

There's a chance I'm wrong here because I'm not in a 68k assembly mindset right now, but it looks like most drives in the list do care about seeing the Apple response, with the exception of the first 6: Seagate ST225N/ST250N, Rodime RO632, Quantum Q250/Q280, and Miniscribe M8425. It might be interesting to play with a SCSI2SD sometime to verify that.

This makes a lot of sense. And this list of free pass disks will be bigger in Drive Setup. Seagate seems to get almost universal approval - the Seagate entry has a wildcard after just the first two letters or so of the part name, which is most Seagate disks.

That is why I raised this - I mostly have Seagate SCSI disks and they all just... Work.

Everyone keeps commenting that I might be using patched formatters accidentally, please, I can tell the difference between the patched and unpatched software. I modify copies myself if I need it. I'm talking about fresh from official install CD copies.

Also, I'm not talking about IDE because the Drive Setup just give all IDE drives a free pass, and Mac OS X will format anything on my computers (I don't have anything too recent - I don't run intel or ARM macs).