How to deprecate bits of your program
Since this appears necessary , here is how todeprecate some bit of your program in a way that makes sysadmins hateyou as little as possible.
- first, add a warning to your documentation and a 'compatibilityswitch' that causes your program to use the old behavior that youare deprecating. Of course, the compatibility switch currently doesnothing since the old behavior is the current behavior, but nowyou've let people start explicitly specifying that they need theold behavior.
If you are changing the behavior of your program
Some more thinking about requirements in specifications
Aristotle Pagaltzis 's comment on my previous entry prodded me into doing somemore thinking about this, and his entry on RFC 2119 usage has persuaded me that thereare actually four degrees of requirements that it's useful toput into specifications.
Put simply, I'd say that they are:
- allowed: you can do this, and some people will (so be prepared to copewith it).
- recommended: we think that you should do this.
- should: not doing this causes problems for
不太完美的句號
Forgetful
The article teaches us to ask if the forgetful patient is paying his bills. Does he forget his way and get lost? A quick assessment of the severity of cognitive impairment, I was told, should include orientation to place, recall of three items and general knowledge such as news headlines. And something like that.
"Oops, are they talking
Lady First 專欄（58）
七月蘋果 (2009)
「由七月一日凌晨起，全港超過一千三百間娛樂場所，包括酒吧、會所、夜總會等，須即時執行室內禁煙條例，實施全面禁煙……」一看到「酒吧」兩字，媽媽不得了，立時仰天長嘆，眼角湧出兩滴淚水，酒吧內不
MUST versus SHOULD in your specifications
Something I've been mulling over lately is the the effects of A rulefor Internet software on specifications and how strongyou make requirements in them.
To put it one way: a 'MUST' in a specification makes a handy club tobeat people with, but perhaps they are best reserved for things thatare absolutely required in order to make the protocol work, becausein practice that is what is going to happen anyways.
(Note that a MUST often does not make an effective club, because ifit doesn
拜託，我不是來自中國的孤兒…
ZFS changes filesystem device numbers on reboot
Here is an unpleasant discovery that we just finished making: in atleast Solaris 10 U6, ZFS changes the device numbers of all of yourfilesystems when your system reboots . More specifically (and evenworse), the device numbers of a pool's filesystems change wheneverthe pool is imported, including the implicit import that happenswhen a system boots up.
(This raises interesting questions of how NFS filehandles keepworking across system reboots, which they do. Presumably theyhave some other stable identifier for a given