Sam James thesamesam

macOS Internals

Understand your Mac and iPhone more deeply by tracing the evolution of Mac OS X from prelease to Swift. John Siracusa delivers the details.

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A Selected List of Additions and Changes Coming With POSIX Issue 8

Last major change: 10th March 2023

See Also: http://mywiki.wooledge.org/POSIX#Utilities

New Commands

** text licensed under CC-BY 4.0 https://creativecommons.org/licenses/by/4.0/legalcode

porting gentoo (ppc32 musl example)

install crossdev
add musl repo to the system if doing musl port.
You don't have to enable it in system, just have a fresh checkout in /var/db/repos/musl
prepare crossdev repo

https://wiki.gentoo.org/wiki/Custom_ebuild_repository#Crossdev

What is the Strict Aliasing Rule and Why do we care?

(OR Type Punning, Undefined Behavior and Alignment, Oh My!)

What is strict aliasing? First we will describe what is aliasing and then we can learn what being strict about it means.

In C and C++ aliasing has to do with what expression types we are allowed to access stored values through. In both C and C++ the standard specifies which expression types are allowed to alias which types. The compiler and optimizer are allowed to assume we follow the aliasing rules strictly, hence the term strict aliasing rule. If we attempt to access a value using a type not allowed it is classified as undefined behavior(UB). Once we have undefined behavior all bets are off, the results of our program are no longer reliable.

Unfortunately with strict aliasing violations, we will often obtain the results we expect, leaving the possibility the a future version of a compiler with a new optimization will break code we th

	# ruby's git repo investigation zsh one-liner-ish thingy
	# (a starting point for investigating anomalous contributions in git repositories)

	echo "$(find . -type f ! -size 0 ! -path './.git*' -exec grep -IL . "{}" \;)" \| \
	sed -e "s/^\.\///g" \| \
	while read line; \
	do \
	echo ">>>>>>>>$line"; \
	echo "$(git log --follow --find-renames=40% --pretty=format:"%ad%x0A%h%x0A%an%x20<%ae>%x0A%s" -- "$line" \| head -n 4)"; \
	commitdates="$(git log --follow --find-renames=40% --pretty=format:"%ae" -- "$line" \| head -n 1 \| xargs -I {} git log --author={} --pretty=format:"%ad")"; \

	#!/usr/bin/env bash

	#
	# This script attempts to recover a ZFS filesystem afflicted by the bug described in
	# the following GitHub issues:
	#
	# * https://github.com/openzfs/zfs/issues/13859
	# * https://github.com/openzfs/zfs/issues/13521
	# * https://github.com/openzfs/zfs/issues/13709
	#

	#!/usr/bin/env bash
	#
	# Author: Markus (MawKKe) [email protected]
	# Date: 2018-03-19
	#
	#
	# What?
	#
	# Linux dm-crypt + dm-integrity + dm-raid (RAID1)
	#