High Sierra on 2019+ intel iMacs

[Honeyko]

Device: iMac19,2 (a 21.5" 4K 3.6ghz i3 with 8gb ram and a 1TB rotational drive).

Situation: I already have a 'master' High Sierra installation on an external SSD.

Problem: While I don't get the "No!" slashed-zero, booting hangs at third-of-the-way.

Goal: Patch High Sierra (add kexts, or whatever) to launch 2019+ intel Macs.

Important consideration: OS must launch from HFS+ partition on a rotational drive.

 

Annoyance: Mojave (oldest OS supported on 2019+ hardware) can run from an HFS+ partition (via Carbon Copy Cloning from its installed APFS container into a prepared HFS+ partition), and does run on the 2019s, but is noticeably slower with higher memory consumption than High Sierra (using up an extra 1gb to 2gb at-rest on a fixed-8gb machine). This results in a 2019 machine with inferior performance compared to a similar 2012 21.5" with a slower processor running High Sierra. Needless to say, upgrading to any Catalina or newer OS (e.g., System Preferences pesters me to upgrade to Ventura) will result in an APFS-formatted rotational drive being thrashed to pieces (so we're not going to do that; additionally, 32bit support ends with Catalina, meaning no CS6 for quick-n-dirty photo edits, and no Peggle or Angry Birds for the kids).

 

There are lots of guides on how to install newer OSes on older unsupported machines, but a dearth of those patching older unsupported OSes to run on newer machines. Help me out. TIA. (The ideal solution would be a DosDude-style post-installation patcher.)

 

(If a mod could move this to the most appropriate sub-forum, I'd appreciate it. TIA)

[Slice]

Your question is good for this subforum.

But tell me why not Mojave on APFS? HFS+ format is ancient having bugs.

[deeveedee]

@Slice  Some people believe that APFS is not well-suited to mechanical (spinning) boot HDs.  Maybe the OP thinks they need HFS+ for a mechanical (rotational) drive?  I use APFS on mechanical drive for Time Machine, but haven't used APFS on mechanical boot drive.

Edited January 28, 2023 by deeveedee

[Slice]

2 hours ago, deeveedee said:

@Slice  Some people believe that APFS is not well-suited to mechanical (spinning) boot HDs.  Maybe the OP thinks they need HFS+ for a mechanical (rotational) drive?  I use APFS on mechanical drive for Time Machine, but haven't used APFS on mechanical boot drive.

I see no dependency. I am using APFS on mechanical drives without an issue.

[Honeyko]

On 1/28/2023 at 3:42 AM, Slice said:

But tell me why not Mojave on APFS? HFS+ format is ancient having bugs.

1. HFS+ problems are easy to solve, and the only remaining "bugs" from Apple's corporate perspective are "security"-related (and I put that word in quotes for a reason, as, like all the apex tech companies, Apple is now primarily a data-collection agency wearing a computer manufacturing division as a skin-suit). Hilariously, Apple's own temporary install partitions for its APFS operating systems remain HFS+ (they're deleted after set-up, so you don't notice).

 

2. While Mojave ostensibly is the last OS that ran 32bit apps, it's horrendously full of bugs (while High Sierra itself was a no-new-features bug-patched version of the original Sierra. Notably, Adobe Create Suite 6 breaks in Mojave, and I can think of little excuse for it other than Apple and Adobe colluding to deliberately kill off that "old" stand-alone suite to herd everyone into the bloated, sluggish, subscription-model "Creative Cloud" versions. (Photoshop Extended CS6 launches in two seconds flat on High Sierra from a Fusion drive, and not much longer on a purely rotational system.)

 

3. The primary purpose of APFS is to tighten the noose and "close" the operating system, not to fix bugs (of which it introduced more than it allegedly fixed). Especially Apple doesn't want anybody using non-AppStore-carrying utilities to easily clone a bootable backup of their drive. The only notable aspect of APFS that is desirable to me is the "Volume" format scheme (as opposed to partitioning) that shares leftover drive space and permits all volumes to store their startup caches in the SSD portion of Fusion drives (which shrank drastically in 2015)...but most people only ever have one volume on their Mac, and users that'd want more than one are often techs like me who need to clone various OS sets, which we can't do in APFS with any MacOS tool that I am aware (e.g., CarbonCopyClone and GetBackupPro are just straight worthless in APFS, even though they're somehow still charging money for products that fail at their "one job").

 

4. High Sierra isn't as old as you think: it debuted in September 2017! There's no reason it can't run on any intel processor, including i9s. In fact, it'll load about two-thirds of the launch progress bar if attempting to start a 2019 machine, indicating that it's proceeding fine until it chokes due to lack of the right kexts. It does NOT just immediately splash a slashed-circle on the screen. Squelching High Sierra only fifteen months after its debut was an exercise in pure artificial obsolescence. It was too good, and therefore had to die. It's hard to justify high-end bleeding-edge machines requiring 32gb or more of ram when High Sierra would run ten open productivity applications (including a browser with fifty open tabs) using little more than half of 16.

 

 

On 1/28/2023 at 11:16 AM, Slice said:

I am using APFS on mechanical drives without an issue.

For the time being you are. APFS is notably slower on rotationals due to the way it catalogs; essentially more info is saved with the application file rather than in a catalog-file. Catalogs are typically stored in the earliest sectors of a drive (meaning the fasted portion or outer rings of a rotational drive, or the SSD portion of a Fusion drive), whereas under APFS that information is sprinkled all over the place, resulting in the rotational drive's read-write arm skittering constantly. This wears them out faster than normal (as utilities like DriveDr will easily attest), and, with all machines now being glued together, results in perfectly fine machines being chucked because of the difficulty of disassembly/reassembly.

 

I will be told that APFS is "designed for SSDs". True enough, in the sense that it's murder on pure-rotational systems (did you know Apple was still making pure-rotational machines in 2019?), but that shouldn't be construed as meaning that it runs better on SSDs than HFS+, because it doesn't.

 

(Side note: I have an old "white" Imac with two 512mb sticks of whatever slug-speed ram Apple used in the day. It only takes fifteen seconds for a Snow Leopard partition on an aging 320gb USB2 external to launch that 1gb-of-ram computer.)

 

~ ~ ~

 

In any event, does anyone here know of a repository of kexts/drivers/etc for various 2018/19/20/21 intel-series Macs? (It should then be a simple to drop these into High Sierra to determine what's missing.)

[Slice]

Quote

While Mojave ostensibly is the last OS that ran 32bit apps, it's horrendously full of bugs (while High Sierra itself was a no-new-features bug-patched version of the original Sierra

Where is the proof? Mojave works fine. No bugs.

But I several times felt into HFS+ bugs when I can no more repair file system "We will mount the system read-only for you to save your critical data, bla-bla....". Apple can't repair broken HFS+ File System!

Several times.

Quote

I will be told that APFS is "designed for SSDs". 

It's your fantasy. OS operates with bytes, sectors and your drive is just an array of sectors, no more. It doesn't know a physical carrier of these sectors.

[Honeyko]

1 hour ago, Slice said:

....several times felt into HFS+ bugs when I can no more repair file system "We will mount the system read-only for you to save your critical data, bla-bla....". Apple can't repair broken HFS+ File System!"

And that's when venerable old DiskWarrior5 comes out to fix the problem in five minutes or less 95% of the time. Meanwhile, if an APFS volume breaks, you're screwed if without a recent working Time Machine full archive *and* the full installer for the OS version you were using in another volume or partition (because doing a Command-R reinstall only accesses the base OS that the machine originally came with -- which might be an HFS+ OS!). Even if you have those and get everything working again perfectly, you're still kissing away an hour of your time minimum babysitting a recalcitrant computer, and, importantly, need to know the correct procedure.

 

(Apple could have flipped a dime to buy DiskWarrior and incorporate its features into the Disk Utility at any time, and chose not to. This, in a corporation that famously buys out other companies to incorporate their products, e.g., Claris, Final Cut, etc.)

 

1 hour ago, Slice said:

It's your fantasy. OS operates with bytes, sectors and your drive is just an array of sectors, no more. It doesn't know a physical carrier of these sectors.

 

It's not a fantasy. (Mike Bombich is the creator of Carbon Copy Cloner.)

Edited February 11, 2023 by Honeyko

[Slice]

I know DiskWarrior. It is very good application to help Apple to repair his HFS+ in some cases. The way is to find all files and create new catalog.

It just confirms the HFS+ is very bad and glitching file system.

[Honeyko]

10 hours ago, Slice said:

I know DiskWarrior. It is very good application to help Apple to repair his HFS+ in some cases. The way is to find all files and create new catalog. It just confirms the HFS+ is very bad and glitching file system.

 

The mechanics of HFS+ were not bad; Apple's lazy-ass, non-redundant, fragile implementation of it was bad. (Notably, Disk Utility just flat sucked at solving anything more-than-minor glitch, and its Linux-kited "Sync" base code wasn't updated for something like ten straight years.)