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Groups > comp.sys.mac.system > #119630

Re: APFS on HDD

Subject Re: APFS on HDD
Newsgroups comp.sys.mac.system
References (19 earlier) <1nyiqcn.1rpsrwgn7nqxdN%dempson@actrix.gen.nz> <slrnpv4ji7.2rih.g.kreme@Snow.local> <1nyjfdg.1hv789t1vxto1uN%dempson@actrix.gen.nz> <OKKID.690429$cL2.332255@fx43.iad> <1nykn4g.hu7ekw3xspluN%dempson@actrix.gen.nz>
From JF Mezei <jfmezei.spamnot@vaxination.ca>
Message-ID <dphJD.1096081$RN2.443580@fx40.iad> (permalink)
Date 2018-11-21 13:24 -0500

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On 2018-11-19 22:28, David Empson wrote:

> Have you never booted a Mac while holding down the Option key?


> The Startup Manager predates Apple's use of EFI: 

The firmware in a PPC mac was totally different and proprietary to
Apple. That the statup manager on an 8086 may appear similar in function
does not mean it was implemented in the same way.

> How can a Startup Manager be loaded from disk at a point where no disk
> is connected to the computer? On a Mac with no drives,

OK, touché.  I hadn't thought of that.  I have to wonder how it is done
since EFI standards don't provide for a GUI. And you're correct, if it
is able to parse through an APFS volume to find bootable media, then it
must have APFS knowledge.

However, consider a case when the startup manager is an EFI application.
As such the EFI itself still doesn't need to understand APFS. This may
be semantics, but consider a case where machine boots itself after a
power failure. This would be an EFI only process where it reads block 0
of default boot volume type of stuff at which point it doesn't need
knowledge of the file system (as per the APFS reference manual).

But, if the startup manager is available without any disks, then it must
be stored in firmware. So I was wrong on that. Whether it is part of EFI
or an EFI application does have important distinctions though.

> Not "hidden". Nonexistent. There is no text console in the EFI firmware
> on Intel Macs. Apple uses a modified version of EFI.

Text consoles are provided on many types of server machines. They are
considered EFI applications.

There is a big distinction though between EFI booting, and in doing so
seeks to boot an OS, and loading an application with no intentions to
boot. (such as loading a text console or a hardware test programme)

The startup manager is invoked as part of a boot process which is
switched to a different boot file (sicha s startup manager EFO
programme) because of keys being pressed on keyboard.  As such, the EFI
has begun to transfer control to the file/program it has loaded with no
expectation of a return to it.


> I don't yet know how the Startup Manager finds out about multiple
> bootable volumes in an APFS container. That is either built into the
> firmware or achieved via an EFI driver loaded from disk which extends
> the firmware Startup Manager.

Must be firmware. Your experiment of booting startup manager with no
disks, and then seeing AFPS volumes appear when you plug the drive in
would mean the Startup Manager code would already have the knowledge to
parse that newly connected drive.

In another message, you mentioned the byte code interpreter.  When IA64
(Itanic) came out, they decided EFI programs should be in x86 code, so
on platforms that were not X86, the EFI had a built-in X86 translator
into IA64 instructions. The EFI programs would be compiled with X86
output.  (as opposed to a Java environment where it has its own
instruction set which is then interpreted).

Not sure how this works on a native X86 box where the EFI need not
translate the EFI programs.  But even if it did translate them, it
doesn't mean it would control them. EFI would simply provide the
environment for the EFO program to run. In a boot scenario without any
expectation that control would return to it since the EFO program would
load the OS boot file and branch to it.

While EFI no longer run the logic, its syystem calls remain available
for the booting OS. There are services to provide hardware config, read
the boot disk, and output to screen with primitive text interface (and
access keyboard).

So when you boot -V , the text display you see is text which OS-X asks
EFO to display before OS-X has setup its own graphics software.
Simularly, the initial part of the boot reads the system disk using EFI
drivers until OS-X itself has loaded its disk drivers. (I learned the
hard way with Yosemite which disabled a kernel extension I had, so boot
would hang at the place where OS-X trioed to mount the boot drive itself)

With APFS encryption, I am not sure how they worked the early boot
sequence in terms of disk access. The EFI boot loader program on disk
will ask for the password and be able to read the OS' boot blocks using
EFI disk reading and decrypt the data. But once it branches to the OS
instance's BOOT.EFI, not sure how long the OS-X relies on the EFIO disk
driver (and then manually decrtpt stuff) before loading its own disk
driver that reads and decrupts.

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Thread

Re: APFS on HDD rs99tl@gmail.com - 2018-11-09 17:32 -0800
  Re: APFS on HDD Your Name <YourName@YourISP.com> - 2018-11-10 14:42 +1300
    Re: APFS on HDD RSORLANDO <rs99tl@gmail.com> - 2018-11-09 18:15 -0800
    Re: APFS on HDD Elden <usenet@moondog.org> - 2018-11-09 21:27 -0800
      Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-10 18:52 +1300
        Re: APFS on HDD J Burns <burns@nospam.com> - 2018-11-10 09:11 -0500
          Re: APFS on HDD Your Name <YourName@YourISP.com> - 2018-11-11 10:08 +1300
            Re: APFS on HDD J Burns <burns@nospam.com> - 2018-11-10 17:41 -0500
              Re: APFS on HDD nospam <nospam@nospam.invalid> - 2018-11-10 19:18 -0500
              Re: APFS on HDD Your Name <YourName@YourISP.com> - 2018-11-11 18:03 +1300
                Re: APFS on HDD J Burns <burns@nospam.com> - 2018-11-11 13:21 -0500
                Re: APFS on HDD Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-11-12 03:09 +0000
                Re: APFS on HDD J Burns <burns@nospam.com> - 2018-11-12 02:10 -0500
                Re: APFS on HDD Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-11-12 12:32 +0000
                Re: APFS on HDD Your Name <YourName@YourISP.com> - 2018-11-13 08:14 +1300
                Re: APFS on HDD J Burns <burns@nospam.com> - 2018-11-12 20:29 -0500
                Re: APFS on HDD Your Name <YourName@YourISP.com> - 2018-11-13 18:15 +1300
                Re: APFS on HDD J Burns <burns@nospam.com> - 2018-11-13 09:20 -0500
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-12 02:30 -0500
                Re: APFS on HDD Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-11-12 12:45 +0000
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-12 18:31 -0500
                Re: APFS on HDD Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-11-13 00:04 +0000
                Re: APFS on HDD Your Name <YourName@YourISP.com> - 2018-11-13 13:46 +1300
          Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-11 15:55 +1300
            Re: APFS on HDD J Burns <burns@nospam.com> - 2018-11-10 23:38 -0500
            Re: APFS on HDD Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-11-11 07:18 +0000
              Re: APFS on HDD J Burns <burns@nospam.com> - 2018-11-11 12:39 -0500
                Re: APFS on HDD Your Name <YourName@YourISP.com> - 2018-11-12 09:10 +1300
                Re: APFS on HDD J Burns <burns@nospam.com> - 2018-11-11 19:26 -0500
                Re: APFS on HDD Your Name <YourName@YourISP.com> - 2018-11-12 16:20 +1300
                Re: APFS on HDD J Burns <burns@nospam.com> - 2018-11-12 01:46 -0500
            Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-14 02:05 +1300
        Re: APFS on HDD Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-11-11 07:13 +0000
          Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-12 02:10 -0500
        Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-12 02:02 -0500
          Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-12 21:57 +1300
            Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-12 18:26 -0500
              Re: APFS on HDD Jolly Roger <jollyroger@pobox.com> - 2018-11-13 01:12 +0000
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-12 23:44 -0500
                Re: APFS on HDD Jolly Roger <jollyroger@pobox.com> - 2018-11-13 18:17 +0000
              Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-13 19:38 +1300
                Re: APFS on HDD Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-11-13 10:21 +0000
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-13 05:55 -0500
                Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-14 01:28 +1300
                Re: APFS on HDD Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-11-13 13:40 +0000
                Re: APFS on HDD Jolly Roger <jollyroger@pobox.com> - 2018-11-13 18:18 +0000
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-13 05:57 -0500
                Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-14 01:28 +1300
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-13 13:27 -0500
                Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-14 13:31 +1300
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-14 15:33 -0500
                Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-15 12:04 +1300
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-15 00:35 -0500
                Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-15 22:24 +1300
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-15 12:39 -0500
                Re: APFS on HDD Stephen Hoffman <seaohveh@hoffmanlabs.invalid> - 2018-11-16 13:45 -0500
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-16 20:13 -0500
                Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-18 18:37 +1300
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-18 17:40 -0500
                Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-19 13:42 +1300
                Re: APFS on HDD Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-11-19 02:08 +0000
                Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-19 15:52 +1300
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-18 22:31 -0500
                Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-20 13:23 +1300
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-19 23:32 -0500
                Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-20 22:05 +1300
                Re: APFS on HDD "David B." <"David B"@nomail.afraid.org> - 2018-11-20 09:36 +0000
                Re: APFS on HDD André G. Isaak <agisaak@gm.invalid> - 2018-11-20 06:12 -0700
                Re: APFS on HDD "David B." <"David B"@nomail.afraid.org> - 2018-11-20 14:28 +0000
                Re: APFS on HDD nospam <nospam@nospam.invalid> - 2018-11-20 09:36 -0500
                Re: APFS on HDD nospam <nospam@nospam.invalid> - 2018-11-20 08:57 -0500
                Re: APFS on HDD "David B." <"David B"@nomail.afraid.org> - 2018-11-20 14:34 +0000
                Re: APFS on HDD nospam <nospam@nospam.invalid> - 2018-11-20 09:36 -0500
                Re: APFS on HDD Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-11-19 05:46 +0000
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-19 02:27 -0500
                Re: APFS on HDD Stephen Hoffman <seaohveh@hoffmanlabs.invalid> - 2018-11-19 11:42 -0500
                Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-20 13:23 +1300
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-19 21:57 -0500
                Re: APFS on HDD dempson@actrix.gen.nz (David Empson) - 2018-11-20 16:28 +1300
                Re: APFS on HDD JF Mezei <jfmezei.spamnot@vaxination.ca> - 2018-11-21 13:24 -0500
                Re: APFS on HDD Stephen Hoffman <seaohveh@hoffmanlabs.invalid> - 2018-11-19 11:34 -0500
                Re: APFS on HDD Lewis <g.kreme@gmail.com.dontsendmecopies> - 2018-11-13 13:41 +0000
  Re: APFS on HDD Alan Browne <bitbucket@blackhole.com> - 2018-11-11 13:04 -0500

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