Subject: Re: 3c509 again
To: Manuel Bouyer <>
From: Theo de Raadt <>
List: current-users
Date: 06/29/1994 16:04:29
> getting this file to a scsi disk, whith a bustek 445 scsi adapter (VLbus),
> i get 800 Ko/sec 
> getting this file to a scsi disk, whith a adaptec 1542b scsi adapter (isa),
> or to an ide disk, i get between 20 and 50 Ko/s. When hash is on, i can see that
> data comes by 'packets' of variable size (between 1 and 200 Ko); the transfer
> stop for 1/10 to 1 sec between each packets.

> On the same hardware, linux always gives 700ko/sec, even whith /dev/null.
> Any ideas ? If someone suggest some changes to the kernel, i can test them.

BTW: I would suggest you not use ftp to measure. The statistics
printed by ftp are not accurate, especially for files under 1M.  If
you wish to measure performance, use "ttcp", available on numberous
ftp sites.

I've told a few people that I think the problem is because of
interrupt latency. Your measurements confirm what I suspected: People
with good disk controllers have good performance, everyone else