tech-kern archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: Testing 7.0 Beta: FFS still very slow when creating files



    Date:        Mon, 25 Aug 2014 20:08:03 -0600
    From:        Sverre Froyen <sverre%viewmark.com@localhost>
    Message-ID:  <E88CBABB-1884-412B-A447-7541ABFB7E13%viewmark.com@localhost>

  | Does the NetBSD version originate with BSD? The man pages for FreeBSD,
  | OpenBSD and Mac OS X all have the same description.

Yes, and of course, as they all documented what the BSD implementation did
(that is just subtract bytes until a non-zero value resulted, or end of data).

But there never really was a requirement that it be implemented that way, an
architecture with a byte string compare instruction might leave the results
in the condition codes, which could be translated to -1, 0, 1 and meet the
implementation requirements - testing <0, ==0, or >0 are the only defined
actions on the result - any code assuming that the result tells the
magnitude of  the difference between the first bytes that differ (which
would be a truly bizarre thing to care about, given there's no way to
discover from the result which bytes differed) would be broken.

kre



Home | Main Index | Thread Index | Old Index