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> They ditched that once Rosetta support on ARM Macs was good enough to run x86_64 VMs, as apparently all they cared about was supporting Docker on Macs...

Was a research project gone out of hand, arm64 macOS wasn't on the radar and the IoT product it was released for didn't succeed.

> I think it is essentially "complete drawbridge", too. I haven't played around with it in a while, but from memory, you can coerce it to run arbitrary Windows executables, basically anything without graphics (which are missing from the PAL they ship).

sbtrans (for arm64) was static binary translation only. No JIT fallback whatsoever.

> It's quite impressive, though also necessary if you think about it. SQL Server requires the legacy dot net stack,

The arm64 sbtrans-based version had that gone too, and it didn't have a nice engineering path towards supporting those. It'll come back later though I'm pretty sure, with using a more native arm64 version (or arm64EC which exists nowadays)

> AND it also ships with a full copy of the msvc compiler/linker! Not sure if that's ever used by the Linux port, but it is installed. MSSQL kind of exercises every inch of the Windows API surface.

Yes that's used for dynamic query optimisation. It was disabled in Azure SQL Edge for arm64 as that was a JIT-less translated version.


XNU has this oddity: https://github.com/apple-oss-distributions/xnu/blob/f6217f89...

Redacted from open source XNU, but exists in the closed source version


Is it actually redacted, or just a leftover stub from a feature implemented in silicon instead of software? Isn't the x86 memory order compatibility done at hardware level?


Redacted


After Power9, IBM became uncompetitive multi-core performance against mainstream server CPUs - both x86 and Arm. They didn't keep up with the rise in core counts.

And the single thread side isn't that good either, but SMT8 is a quite nice software licensing trick


Xcode needs an Apple ID for download but the macOS SDK and toolchain does not.

Try to run any developer tool or "xcode-select install" and it'll download the command-line tools independently from Xcode.

(and then bring your own IDE)


There were two entirely separate DOS 4s

The multi-tasking DOS 4 that had its next release be branded as OS/2

and the other one, a conventional DOS stopgap product


Note that UEFI doesn't mean supporting most of those.

UEFI without runtime UEFI variable writes is a thing, and that configuration is incompatible with mokutil.


FWIU,

There is no SecureBoot without UEFI.

UEFI without SecureBoot does have advantages over legacy BIOS with DOS MBR.

> UEFI without runtime UEFI variable writes is a thing

Which vendors already support this?

Do any BIOS - e.g. coreboot - support disabling online writes to EFI? (with e.g. efibootmgr or efivar or /sys/firmware/efi)

One of the initial use cases for SecureBoot is preventing MBR malware.

What there be security value to addding checksums or signatures as args to each boot entry in grub.cfg for each kernel image and initial ramdrive?

Unless /boot is encrypted, it's possible for malware to overwrite grub.cfg to just omit signatures for example.


> Which vendors already support this?

One implementation I've seen in the wild is: https://docs.nvidia.com/jetson/archives/r36.4/DeveloperGuide...

Secure Boot is still supported in that configuration, but with PK/db/dbx being part of the firmware configuration and updating them requiring a UEFI capsule update.


Looks like UKI include the initrd in what EFI checks the signature of.

Add signature checking for grub.cfg (instead of just the EFI shim) but that requires enrolling a local key

Add initrd signatures to grub.cfg


U-Boot nowadays speaks UEFI :) (and so does LK)

New Android devices all use a UEFI bootloader: https://source.android.com/docs/core/architecture/bootloader...


Side note: USB 3 Lightning did exist on iPad Pros.


No. It existed with one special adapter.


SME2 is restricted in scope to matrix multiply workloads and isn't really designed for anything else.

The point of streaming SVE is to have a way to pre/post process data on the way in or out of a matrix multiply.

A list that I have around of chips which support various levels of SVE:

For SVE(1) deployment, chips that have it: - Fujitsu A64fx - AWS Graviton3

SVE2: - Snapdragon X2, 8/8 Elite Gen 5 and later - MediaTek Dimensity 9000 and later - NVIDIA Tegra Thor and later, NVIDIA "N1" or later (GB10 is an "N1x" SKU) - Samsung Exynos 2200 or later - AWS Graviton4, Microsoft Cobalt 100, Google Axion (and newer chips) - CIX P1

SME(1) instead of SME2:

- Snapdragon X2, 8/8 Elite Gen 5

SME2:

- Apple M4, A18 and later - Samsung Exynos 2600 - MediaTek Dimensity 9500

Note that the Snapdragon 8/8 Elite Gen 5 and X2 support sve2 but not svebitperm.


Qualcomm was odd like that for a long time yeah.

And yes the Gen 5 chips (8, 8 Elite and X2) do implement SVE2 and SME.


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