Archive for March 30, 2020

Monday, March 30, 2020

Xattrs Make Time Machine Backups Waste Space

Howard Oakley:

When metadata used to change relatively infrequently, this had little in the way of adverse effects. Now that security and privacy protection are doing so much with extended attributes, the unintended consequence is that many of the files which are copied into each Time Machine backup haven’t actually changed in substance, but a quarantine flag has been added, for instance.

It’s easy to demonstrate this in action if you’re making Time Machine backups. Simply create a sizeable PDF file which doesn’t have a quarantine flag attached to it, or strip the flag from a file which already has one. Leave the file alone for the next automatic backup. After that, open the document using Preview, which will in a fraction of a second automatically write a quarantine flag to it. Leave it for the next automatic backup, and that backup will contain a second copy of that PDF which only differs in that quarantine flag, maybe as little as 31 bytes in all. Imagine this happening to many 10 GB movie clips and you see where this is heading.


“Cursor,” “Pointer,” and “Insertion Point”

John Gruber:

For clarity, it’s best not to refer to either of these things as cursors. Instead:

  • Mouse/trackpad pointer.
  • Insertion point.

This terminology has been slightly confusing over the last week, since Apple’s surprise announcement of pointer support in iPadOS 13.4. In their marketing materials, Apple is calling pointers “cursors”.


In its technical documentation, Apple is clear.

The new API calls it a “pointer,” but Carbon and Cocoa have historically used “cursor.” Of course, “pointer” also has another meaning in code.

Dr. Drang:

For 35 years, Apple’s been telling me this thing should called a pointer, and I’ve been following along, mainly because I thought the distinction between a pointer and a cursor was useful.