Date: Sat, 7 Oct 1995 19:42:26 -0400 (EDT) From: Chuck Robey <chuckr@eng.umd.edu> To: Bruce Evans <bde@zeta.org.au> Cc: dennis@etinc.com, hackers@freebsd.org Subject: Re: VLB Disk Controllers Message-ID: <Pine.SUN.3.91.951007193617.4730A-100000@cappuccino.eng.umd.edu> In-Reply-To: <199510072115.HAA03150@godzilla.zeta.org.au>
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On Sun, 8 Oct 1995, Bruce Evans wrote: > >Justin Gibbs says, > > >>>Adaptec, Buslogic. Any possitive or negative comments on the drivers would > >>>be welcome. > >>> > >>>Dennis > >> > >>The 2842 seems to work well, supports tagged queuing and other advanced > >>SCSI II features that the buslogic (may be a driver limitation) does not. > >>The adaptec has much lower command overhead than the buslogic > > That's not saying much. An IDE controller has a much lower command > overhead than the buslogic: Bruce, I have tried that on my 486/66, using a 2842 with a Seagate ST42100, and I notice that I get different results every time I run it, do you know why? If that's supposed to be, then the results of that program really should be averaged, across multiple invocations before they really would show that accurately. > > Buslogic BT44C on 486DX2/66 VLB TOSHIBA MK537FB (slow disk): > Output for disklatency /dev/rsd0: > Command overhead is 4741 usec (time_4096 = 5164, time_8192 = 5586) > transfer speed is 9.6955e+06 bytes/sec > > Buslogic BT44C on 486DX2/66 VLB (QUANTUM XP34301 (fast disk): > output for disklatency /dev/rsd1: > Command overhead is 3968 usec (time_4096 = 4295, time_8192 = 4622) > transfer speed is 1.25286e+07 bytes/sec > > Cheap IDE on 486DX/33 ISA SAMSUNG SHD-3212A (slow disk): > output for disklatency /dev/rwd0: > Command overhead is 573 usec (time_4096 = 2830, time_8192 = 5087) > transfer speed is 1.81489e+06 bytes/sec > [rest deleted to save mail bw] ----------------------------+----------------------------------------------- Chuck Robey | Interests include any kind of voice or data chuckr@eng.umd.edu | communications topic, C programming, and Unix. 9120 Edmonston Ct #302 | Greenbelt, MD 20770 | I run Journey2 and n3lxx, both FreeBSD (301) 220-2114 | version 2.2 current -- and great FUN! ----------------------------+-----------------------------------------------
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