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Date:      Wed, 8 Feb 1995 09:47:18 -0800 (PST)
From:      "Justin T. Gibbs" <gibbs@estienne.CS.Berkeley.EDU>
To: (Javier Martin Rueda)
Subject:   Re: PCI/VESA peripherals for FreeBSD 2.0
Message-ID:  <>
In-Reply-To: <598*/S=jmrueda/OU=diatel/O=upm/PRMD=iris/ADMD=mensatex/C=es/@MHS> from "Javier Martin Rueda" at Feb 7, 95 06:20:42 pm

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> Hi. I'm about to purchase a 486DX2-66 PC to install FreeBSD 2.0 in it and
> use it as a server for NFS, printers, etc.
> Among its requirements, I have to use a fast SCSI-II controller, and a fast
> Ethernet network adapter. I want to use either PCI or VESA cards for those
> two, as I think that will be the fastest. Am I right? Would EISA be faster?
> First of all, I remember someone posted a few months ago the hardware used
> for freefall (24 Gb of disk, 90 MHz Pentium, PCI,...). Can someone e-mail me
> that again, please?
> Regarding VLB SCSI controllers, I've used and tested the Adaptec 2842 VLB
> with a Conner CFP-1060S drive in a 486DX-50, and IOZone reports about 1.5-2
> Mb/sec for writing and 2.5-3.3 Mb/sec for reading (I've excluded figures
> that are too high for reading speed because of the Unix cache).

The 2842 is maxing out your drive.  I hit 5MB/s+ (fsynced writes) to my 
Quantumm Empire 2100 all the time.

> Regarding PCI SCSI controllers, I haven't tested any.
> I'd appreciate that someone e-mail me the speed report generated by iozone
> with different SCSI controllers, specially the PCI controllers supported by
> FreeBSD (Buslogic 946c and NCR 53810). Is the Adaptec 2940 supported
> already, or support isn't ready yet? By the way, what does the 2940 have, so
> that it is about 4-5 times more expensive than the NCR, for example?

In raw speed, I would expect them to be the same.  The question about
performance differences between the two might become a factor when you
have multiple busy targets.  Stephan has said that the transactional
overhead for the NCR is low, but I believe the aic7xxx based cards are
lower.  The NCR driver does, however, have tagged queuing support now,
whereas in the aic7xxx driver, this is work in progress.  The major
reason for a difference in price is that the aic7xxx based cards have
SRAM for their downloaded "seqeuncer" program and SCBs (SCSI Command Blocks).
The NCR DMAs all of this from the host system during program execution.
To be perfectly honest.  Until we get two of these controllers together
for some head to head comparisons there is no way of really knowing.

> With respect to Ethernet adapters, I have no experience with VESA or PCI
> ones. The release notes list a lot of network adapters supported by FreeBSD,
> but they don't say if they are ISA, EISA, PCI or VESA. Does that matter?
> For instance, I've seen VESA network adapters that are compatible with
> NE-2000. Does that mean that they can be used with FreeBSD just as if they
> were 16-bit ISA cards, but much faster?
> Again, I would appreciate reports of people who are using PCI or VESA
> network cards with FreeBSD, specifying the brand and model, and benchmark
> results, if available.
> Thanks in advance. If I get any reports (I hope so :-) ), I will post a
> summary here, just in case there are other people in the same situation.

Justin T. Gibbs
TCS Instructional Group - Programmer/Analyst 1
  Cory | Po | Danube | Volga | Parker | Torus

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