ttydev_cdevsw has no d_purge

[Poul-Henning Kamp]

In message <20120801210210.GU2676 at deviant.kiev.zoral.com.ua>, Konstantin Belous
ov writes:

>> I guess d_purge was added quite recently, right?
>
>No, it was there at least in 2006. In fact, it seems to be added in 2004,
>see r135843.

Ahh yes, I remember that one :-)

It was added so that when PCMCIA cards (anyone remember those ?)
were pulled out, ppp(8) and tip(1) would not stay stuck forever.

Today all devices drivers should assume that the hardware can disappear
under their feet.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.