Grand Central Dispatch
Queue-based concurrency managed by the system rather than by hand, so ordinary applications could use the cores that machines had been shipping with for years.
At launch
- Announced
- June 2008
- Released
- August 28, 2009
- Follows
- Leopard (10.5)
- Followed by
- Lion (10.7)
- Architecture
- Intel only
Overview
Apple shipped a release whose selling point was that it did less.
The marketing said it plainly: zero new features. Snow Leopard spent an entire development cycle on the parts nobody demos — rewriting apps in 64-bit, replacing threading models, deleting PowerPC code — and shipped for £25.
It freed roughly seven gigabytes of disk, installed faster, woke faster, and became the release people stayed on for years afterwards. Its reputation has outlasted almost everything around it: "a Snow Leopard release" is now shorthand across the industry for a version that fixes rather than adds.
Grand Central Dispatch
Multiple cores, without writing thread code.
Instead of every developer managing threads by hand, applications handed blocks of work to system-managed queues and the operating system spread them across whatever cores the machine had. It is still how concurrency is written on Apple platforms.
Work distributed across the available cores
Features
What shipped.
Almost nothing you could photograph. Nearly everything you could feel.
OpenCL
General-purpose computation on the graphics card, opened up to any application. Apple designed it, then handed the standard to Khronos.
At launch
64-bit throughout
Nearly every bundled application rewritten as 64-bit, with a 64-bit kernel on capable machines. Groundwork, unglamorous and necessary.
At launch
Seven gigabytes back
Dropping PowerPC code, compressing binaries and cleaning house returned around 7 GB — on the 128 GB SSDs of the era, a genuinely useful amount.
At launch
QuickTime X
A rewritten player with a chromeless window, GPU decoding, and trimming and sharing built in.
At launch
Exchange support
Mail, Address Book and iCal spoke Exchange 2007 natively, which made the Mac viable in a great many offices that had refused it.
At launch
Dock Exposé
Click and hold a Dock icon to see just that application's windows — Exposé, finally where your hand already was.
At launch
Text substitution
System-wide autocorrect and text replacement, moved out of individual apps and into the text system everything shares.
At launch
Mac App Store
Arrived in January 2011 as a point update — the iPhone's distribution model landing on the Mac more than a year before Lion made it the only way to get the OS itself.
Added in 10.6.6
Legacy
Why people still ask for another Snow Leopard.
The phrase has escaped the Mac entirely. When users of any platform ask for "a Snow Leopard release", they mean a year spent on stability, performance and deletion, with the feature list left deliberately empty.
Apple has never quite repeated it. The closest attempts — El Capitan after Yosemite, High Sierra after Sierra — were pitched in similar language, but both still shipped substantial new work alongside the repairs.
Desktop
The aurora, brighter.
The same aurora as Leopard, pushed into magenta and violet and lit considerably harder — refinement rather than replacement, which was rather the theme.
AuroraThe same light, turned upThere was only ever one. A system-wide Dark Mode did not arrive until Mojave in 2018, so this page's light and dark appearances are ours, not Apple's — the switch in the corner still works, but the desktop of the day looked like this and only this.
Lineage
Where it sits.
Apple named ten releases after big cats before moving to California in 2013.
macOS 10.6 · 2009
Snow Leopard
Almost no new features, on purpose. Grand Central Dispatch, OpenCL, half the disk space.
Compatibility
Machines that could run it.
The first Intel-only release. PowerPC support was removed outright, which is a large part of where the seven gigabytes came from.
- Processor
- Intel
- Memory
- 1 GB
- Disk space
- 5 GB
- Drive
- DVD
- Excludes
- All PowerPC Macs