Code in ARM Assembly: Controlling Flow

Forget about structured code, branching in assembly is based on GOTO with labels. Here’s how to get started, with an idiom for the switch statement in Swift. | Continue reading


@eclecticlight.co | 3 years ago

Code in ARM Assembly: Working with Pointers

Using different addressing modes and offset specifications to load and store in memory. Includes a summary of ARM64 Operand Architecture. | Continue reading


@eclecticlight.co | 3 years ago

Is there still something amiss in the M1 firmware?

Erase your M1’s internal storage in Recovery, reinstall macOS and you could see an error in which it failed ‘to personalize the software update’. That’s not easy to fix, as … | Continue reading


@eclecticlight.co | 3 years ago

Are macOS updates easier than ever?

Big Sur updates have far exceeded those of Mojave or Catalina, and are set to total well over 40 GB. Prospects for security updates are no better, with a high carbon footprint. | Continue reading


@eclecticlight.co | 3 years ago

Code in ARM Assembly: Registers Explained

Types of register explained, and which are available to pass arguments of different types. Call by value and call by reference distinguished. | Continue reading


@eclecticlight.co | 3 years ago

The Elephant at WWDC

Every developer should watch the 5 videos about DocC from WWDC. But it’s really a plaintive cry for help. Until Apple squares up and addresses the problem, it can only grow worse. | Continue reading


@eclecticlight.co | 3 years ago

Code in Assembly for Apple Silicon with the AsmAttic App

First in a series helping you write ARM64 assembly language for M1 Macs. Provides an app within which you can call assembly routines. | Continue reading


@eclecticlight.co | 3 years ago

Which Macs will be officially supported by macOS 12?

Apple should announce macOS 12 next week, but which Mac models will support it? Look in the firmware, not the tea-leaves for this speculative list. | Continue reading


@eclecticlight.co | 3 years ago

M1 Macs have a third Recovery mode

There’s 1 True Recovery, Fallback Recovery and one other recovery mode. Disambiguation, explanation and how this changed in macOS 11.4. | Continue reading


@eclecticlight.co | 3 years ago

It took 6 months for M1 Macs to work properly

Soon after Apple started delivering M1 Macs, users found that they couldn’t boot them from external disks. Six months later, this has largely been fixed. What went wrong? | Continue reading


@eclecticlight.co | 3 years ago

M1 Macs running Big Sur 11.4 support external disks fully

macOS 11.4 has finally fixed all the problems with installing current and older macOS on external disks, and booting an M1 Mac from them. | Continue reading


@eclecticlight.co | 3 years ago

Big Sur 11.4 brings LocalPolicy and recovery access to M1 Macs

What are a new kernel extension and a private framework doing in macOS 11.4? Here are some details, and suggestions for further research. | Continue reading


@eclecticlight.co | 3 years ago

Feeling fast, the psychology of computer performance

We commonly suffer failures of the psychology of Mac performance, when system background tasks overwhelm the processor and bring the interface to a grinding halt | Continue reading


@eclecticlight.co | 3 years ago

M1 Secure Boot, morphine and self-destruction

One command in Terminal which instantly disables any support, and why you can’t (yet) boot your M1 Mac in Linux. | Continue reading


@eclecticlight.co | 3 years ago

M1 Macs feel faster than Intel models: it’s about optimization of CPU QoS

By segregating macOS background tasks on Efficiency cores, M1 Macs can run user apps unfettered on their Performance cores. And that feels really fast. | Continue reading


@eclecticlight.co | 3 years ago

Cores shouldn’t all be the same: M1 Macs do better

How the M1’s asymmetric cores can run background tasks more efficiently, or deliver high performance, according to Quality of Service. | Continue reading


@eclecticlight.co | 3 years ago

iMovie accidently included a provisioning profile in a release

Has the Profiles pane recently appeared in System Preferences? Here’s why – a minor glitch in the App Store update. | Continue reading


@eclecticlight.co | 3 years ago

Apple has pulled Safari 14.1 update for Mojave and Catalina

Included in the macOS updates this week was Safari version 14.1 for Mojave and Catalina (this was also included within Big Sur 11.3 update). Apple has pulled those Safari updates today, apparently … | Continue reading


@eclecticlight.co | 3 years ago

Can you trust floating-point arithmetic on Apple Silicon?

M1 Macs may be as fast as greased lightning, but how good is their numerical accuracy? Can it match that of Intel processors? | Continue reading


@eclecticlight.co | 3 years ago

Enduring file references in macOS (2018)

First there were inodes, aliases, and links. Finder aliases already use the volfs file system, but Apple wants us to switch to its opaque Bookmarks | Continue reading


@eclecticlight.co | 3 years ago

iCloud Secure Backup Comes to macOS

An important feature for many iOS users, this has now appeared in macOS, despite not apparently being exposed to the user. Here’s what I know. | Continue reading


@eclecticlight.co | 3 years ago

Users are losing out against Big Sur’s sealed System

macOS 11.2, 11.2.1 and 11.2.2 have come in quick succession. What do they tell us about how difficult it is to update Big Sur’s sealed System volume? Is this the way to go? | Continue reading


@eclecticlight.co | 3 years ago

How fast SSDs slow to a crawl: thermal throttling

Fast compact external SSDs are prone to thermal throttling. This is demonstrated during tests writing 96 files, when transfer rates fell from 2 GB/s to around 700 MB/s. | Continue reading


@eclecticlight.co | 3 years ago

M1 Macs have another hidden boot mode

Apple has revealed the hidden Fallback Recovery OS mode available on M1 Macs. How to enter and use it, and why it’s another big plus. | Continue reading


@eclecticlight.co | 3 years ago

External boot disks still don’t work properly with M1 Macs

Making an external bootable SSD for an M1 Mac has proved tricky. Has this changed in macOS 11.2? If you’ve already got 11.1 running on one, how do you update it to 11.2? | Continue reading


@eclecticlight.co | 3 years ago

Apple’s Scorched Update Policy

Not only has Apple not provided standalone updaters for macOS 11.2, or for Mojave and Catalina Security Updates 2021-001, but it has removed the Big Sur 11.1 installer. It’s just like iOS now… | Continue reading


@eclecticlight.co | 3 years ago

Don’t trash preference files in macOS Big Sur

Something wrong with the Finder or an app, and you want to trash its preferences? Don’t: macOS will defeat you. Here’s how to do that so it works. | Continue reading


@eclecticlight.co | 3 years ago

Big Sur boot volume layout

Detailed account of disk, volume and folder layouts on Big Sur’s boot disks, complete with roadmaps which are downloadable as PDFs. | Continue reading


@eclecticlight.co | 3 years ago

Stibium 1.0 will now benchmark your SSDs

Improved tests, statistical analysis, and interface, together with a 21 page Help book detailing its range of tests in 5,000 words. Ready to use for real. | Continue reading


@eclecticlight.co | 3 years ago

Macs of the Past and the Future

Processors haven’t just increased in speed and packed more transistors into a smaller space. Features such as the Neural Engine in the M1 show Apple is moving in a different direction. | Continue reading


@eclecticlight.co | 3 years ago

Apple could use a “burst” mode to read the SSD on T2 and M1 chip

Using 140 files of sizes 10 KB – 2 GB, the M1 read files significantly faster than a T2 Mac, but the latter wrote files slightly quicker. Highest read rate on the M1 was 10.8 GB/s, which seem… | Continue reading


@eclecticlight.co | 3 years ago

Give your Mac (imaginary) unlimited storage thanks to Disk Utility’s bug

Disk Utility in Big Sur can turn a 1 TB external disk into 4.5 TB or more of imaginary containers. Sadly it’s just a bug, and here’s how to work around it. | Continue reading


@eclecticlight.co | 3 years ago

Booting an M1 Mac from an external disk: it is possible

If you’ve been unable to create a bootable external disk to use with your M1 Mac, this explains what you need and its limitations and quirks. | Continue reading


@eclecticlight.co | 4 years ago

Apple has stopped providing standalone installers for macOS updates

Apple released macOS Big Sur 11.1 on 14 December. Although yesterday it finally posted standalone installers for the two concomitant security updates to Catalina and Mojave, no standalone updaters … | Continue reading


@eclecticlight.co | 4 years ago

What happens when an M1 Mac starts up?

When does an M1 Mac validate its Sealed System Volume? Who designed its display interface? How soon does Find My Mac launch? So many answers found in the log. | Continue reading


@eclecticlight.co | 4 years ago

Can you trust -the corners- of QuickLook in Big Sur?

It’s enough to make you and Edvard Munch scream: every QuickLook thumbnail and preview has rounded corners. They scream out the arrogance of the designer. | Continue reading


@eclecticlight.co | 4 years ago

Is Big Sur’s system volume sealed?

How can you tell whether your Mac’s shiny new Sealed System Volume is properly sealed? You could easily be misled into thinking it isn’t. | Continue reading


@eclecticlight.co | 4 years ago

macOS has checked app signatures online for over 2 years

Why does it take 2 years to realise that macOS has been checking signing certificate validity online? | Continue reading


@eclecticlight.co | 4 years ago

How to strip Apple Silicon Universal Apps

Will stripping executable code for an unwanted platform stop an app from working? What savings are to be gained? | Continue reading


@eclecticlight.co | 4 years ago

How Big Sur Checks Universal Apps

If you were to strip unwanted code from a Universal App, would it still pass Big Sur’s strict security checks? | Continue reading


@eclecticlight.co | 4 years ago

Checks on executable code in Catalina and Big Sur: a first draft

How macOS checks executable code before it’s loaded and run, in macOS 10.15 and 11.0. Covering integrity checks using hashes, and validity of the signing certificate, on Intel and ARM. | Continue reading


@eclecticlight.co | 4 years ago

Making essential services fail-safe on macOS

Although most were worried about Apple’s failure to deliver upgrades to Big Sur, the most serious problem left many users unable to launch any apps. | Continue reading


@eclecticlight.co | 4 years ago

Time Machine backups waste space

How your Mac’s security and privacy systems can cause duplicate copies of files to be written to your backups. | Continue reading


@eclecticlight.co | 4 years ago

Unified memory blows the SoCs off the M1 Macs

In an M1 Mac, all its main components are tightly integrated and interdependent. To achieve performance with versatility, they come ready-built, not kits. | Continue reading


@eclecticlight.co | 4 years ago

Fragile Finder Comments: worth avoiding

So convenient to use – edit them in the Comments: section of Finder’s Get Info dialog. But as reliable as loose scraps of paper, and as easily lost. | Continue reading


@eclecticlight.co | 4 years ago

macOS Big Sur: Read this before upgrading

Some articles to read before you try upgrading to Big Sur, or ordering a new Apple Silicon Mac. Insights and tips. | Continue reading


@eclecticlight.co | 4 years ago

macOS 11 boot volume layout

A complete guide to the structure and layout of APFS startup disks from High Sierra to Big Sur (Intel), together with tear-out PDF charts. | Continue reading


@eclecticlight.co | 4 years ago

Last Week on My Mac: Is macOS Becoming Unmaintainable?

Provision of maintenance procedures and tools is at the heart of software engineering, but not in macOS. | Continue reading


@eclecticlight.co | 4 years ago