Where’s the Accelerator?

Three recent WWDC sessions extolling Apple’s “extensive reference material” and Xcode can’t find anything on these rich and extensive libraries. | Continue reading


@eclecticlight.co | 4 years ago

Squeezing a thimbleful of update into a ten-gallon can

In macOS 11.5.1, Apple has squeezed a thimbleful of a patch into a ten-gallon can of update, more than 99% of which is overhead. | Continue reading


@eclecticlight.co | 4 years ago

Why are Big Sur updates so large?

The macOS 11.5.1 update fixes a serious vulnerability, but does it really take 2.2 GB (Intel) or 3.1 GB (M1) to fix what could only have been a few MB at most? | Continue reading


@eclecticlight.co | 4 years ago

Is that a thunderstorm coming? macOS 11.6, 12, and Apple Silicon Macs

When should we expect macOS 11.6? When will Monterey be released, and when will the next Apple Silicon models be announced? Here are some wild guesses. | Continue reading


@eclecticlight.co | 4 years ago

Six Years on from Yosemite to Big Sur

Haven’t Macs and macOS changed over the last six years? Here are fictitious diary entries to illustrate the deep-seated changes. | Continue reading


@eclecticlight.co | 4 years ago

Code in ARM Assembly: Floating point registers and conversions

Floating point numbers are very different from integers, but are loaded and stored much the same. Conversion between registers, including to and from integers, is complex. | Continue reading


@eclecticlight.co | 4 years ago

Owners and users: Primary and secondary systems on M1 Macs

M1 Macs have an elaborate system of keys and certificates which allow the installation of second operating systems, as well as the primary OS, based on Ownership. | Continue reading


@eclecticlight.co | 4 years ago

Code in ARM Assembly: Conditions without branches

Where code can make simple selections according to a conditional test, it may be possible to eliminate branching and ensure rapid execution. | Continue reading


@eclecticlight.co | 4 years ago

Are there flaws in some ARM64 instructions?

Many processors like the ARM64 have instructions to perform fused multiply-add operations. Do they deliver reduced error and better performance? | Continue reading


@eclecticlight.co | 5 years ago

The Perils of M1 Ownership

The primary admin account on an M1 Mac is its Owner, responsible for authorising the installation and use of second operating systems. Here’s what can go wrong with Ownership. | Continue reading


@eclecticlight.co | 5 years ago

Is it safe yet to upgrade to Big Sur?

macOS 11.5 will be available in a few days. Should you risk upgrading? Here are some of the major issues which you need to consider when deciding and planning any upgrade. | Continue reading


@eclecticlight.co | 5 years ago

Time has run out on Time Capsules

Most hard disks become increasingly likely to fail after 3 years. All Time Capsules are now in that zone, and should either be replaced or have their hard disks replaced. | Continue reading


@eclecticlight.co | 5 years ago

Code in ARM Assembly: Integer Arithmetic

Basic integer arithmetic – add, subtract, negate, multiply, multiply-and-add, and divide – in their many variations. With some catches for those more used to high-level languages. | Continue reading


@eclecticlight.co | 5 years ago

Code in ARM Assembly: Moving data around

Explaining the LDR family of instructions for loading registers, MOV for moving one register to another, STR for storing to memory, and SXTx/UXTx for filling a register with smaller data types. | Continue reading


@eclecticlight.co | 5 years ago

macOS extensions are moving away from the kernel

Management of kernel extensions has changed significantly in Big Sur and later. This overview for users contrasts kexts with user-level extensions which are replacing them. | Continue reading


@eclecticlight.co | 5 years ago

Code in ARM Assembly: Flow, pipelines and performance

How conditional branching can slow modern processors down badly, comparing assembly code with that generated by Apple’s Swift compiler, and some puzzles. | Continue reading


@eclecticlight.co | 5 years ago

Francisco Goya: 2 Royal cartoons

A wedding and two major commissions: a series of large wall paintings on the Life of the Virgin, and his first 9 cartoons for tapestries, on the theme of hunting. | Continue reading


@eclecticlight.co | 5 years ago

macOS Volume names are still a Unicode mess

Don’t use Unicode normalised Form C names for volumes in Disk Utility, as they cause havoc, and prevent Spotlight from indexing volumes. | Continue reading


@eclecticlight.co | 5 years ago

Code in ARM Assembly: Conditional Loops

How to implement conditional looping such as for and while, and how to break out of a loop. Complete with chart of four conditional idioms. | Continue reading


@eclecticlight.co | 5 years ago

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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 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 | 5 years ago