Ankh Morpork's Finest Coder
Wednesday, December 01, 2004

Ten Most Wanted Design Bugs
This is so enlightening...:-)

Bug #7

Bug Name: The Disk Drive Nazi

Duration: >25 Years

Supplier: Apple Computer Inc.

Slogan: "No computer for you!"

Product: Lisa & Macintosh

Bug: "Unauthorized" removal of floppy or hard disks is punished severely

Class of error: "You're not in charge; we are"

Principle: The user is in charge and should be free to carry out any activity at any time without fear of reprisals


In 1979, the Lisa development team decided that users would not be permitted to remove disks without permission, saving the team from having to work out a way to recover from such an unplanned event. While this was a sharp reversal from the Apple II philosophy, given the Lisa team's RAM limitation (around a thousandth of what many people enjoy today), it was a reasonable compromise.

Let's move forward a quarter century or so. I now use a PowerBook computer. For backup, I've connected an external hard disk using Firewire or, as it's known in the human-oriented world of Windows, IEEE-1394. Periodically, I drag a few newly-created files onto the external disk. Otherwise, it just lays there humming.

In October of 2004, 25 years after the Lisa team's short-cut decision, I put my PowerBook into sleep mode, unplugged my auxiliary hard disk, and travelled 3000 miles to Europe to deliver a series of talks driven by slides from my Macintosh. When I attempted to wake the computer up, however, it failed. Nothing, including an emergency start-up CD-ROM, would allow me to reboot and recover.

Two weeks later, when I returned to the USA, I plugged in my auxiliary hard disk, pressed Power, and the computer started up normally.

Microsoft's GUI has, from the beginning, given users the freedom to remove their disks without notice, recovering quite smoothly from the surprise events. A solution exists. Heaven knows, Microsoft has copied enough from Apple. Turn about is fair play.

Immediate Proposed Fix: Repair boot routine so the system doesn't permanently hang if a previously-used auxiliary disk is not found.

Permanent Proposed Fix: Copy Microsoft's approach, giving Mac users the freedom to plug and unplug without punishment.

Bug first observed: 1979

Observer: Tog

Bug reported to Apple: 1985 (once we had enough RAM to handle a fix: 512k)

Bug on list since: List inception: 1 Dec 2004


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