Subject: Re: DMA
To: Mauricio Tavares <>
From: Curt Sampson <>
List: port-sun3
Date: 01/14/1996 11:07:44
On Sat, 13 Jan 1996, Mauricio Tavares wrote:

> 	Where was I?  Oh, yes.  So I now have a 1GB SCSI2 drive attached
> to the 3/50 replacing the CDC 96141-155.  Currently, it takes quite a lot
> of time to access the drive; for some reason it reminds me of a C64. 
> Would enabling the DMA "mode" speed up this drive so that I will be able
> to load X in my lifetime? 

Can you compile iozone and see what sort of stats you're getting?

I finally did get 1.1 installed on my 3/50 shoebox (it turns out
that it really doesn't like having sd0b before sd0a on the disk,
for some reason--I'd hoped to have my swap space at the beginning
of the disk to minimise head movement) but disk I/O crawled along
at about 20-30 K/sec, which is not unreasonable--for a floppy! I
thought, `Ah ha! I just have to make that change to the SCSI driver,'
which I did. My machine went down in flames.

I should have a newer, faster SCSI drive freed up this coming week
when I replace a drive in my 386 system; I'll try installing on
that and let everyone know how it goes.

> 	In an unrelated topic, how do you rebuild the kernel in NetBSD?  
> In ultrix we had this /usr/sys directory where the kernel config file 
> would be hidden.  Would NetBSD have something similar?

In a sentence? Cd /sys/arch/sun3/conf, make a new MACHINE (probably
by copying another config file) and edit it, config MACHINE, cd
../compile/MACHINE, make depend, make. :-)


Curt Sampson		Info at
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Vancouver, BC   (604) 257-9400		De gustibus, aut bene aut nihil.