Subject: Re: 2940 controllers integrated on the motherboard
To: Andrew Reilly <firstname.lastname@example.org>
From: Justin T. Gibbs <email@example.com>
Date: 04/14/1996 07:59:43
>I can't comment on the PCI-bridge issue, but there was certainly a problem
>with the AIC7850 (2940-ish) controller and the NetBSD aic7xxx driver.
>Fortunately, Justin Gibbs (author of the aic7xxx driver) has just made
>it work for the 7850, so I have high hopes that my IWILL-P54TS motherboard
>based system will soon be running a version of BSD. That will probably be
>FreeBSD at first, because that's where the new driver will probably show up
>first. I'll let you know how I get on. (The 2940 controller cards actually
>have an AIC7870 controller, which has 16 SCBs. The 7850 only has 4, aparently
The IWILL-P54TS is known to work now with the FreeBSD driver. The 7850
only has 3 SCBs. The aic7770 has 4, the aic7870/7880 has 16. Some
3rd party designs may use the memory port on the aic7870/7880 to offer
255 SCBs. I also have work in progress that will allow 255 concurrent
commands on all parts except the aic7770 <= Rev C that uses SCB paging.
>As soon as I'm running, I'll post some benchmarks, to see how that affects
>performance. Since this is a personal workstation, I don't really need
>killer NNTP server level performance. I can say, though, that even under
>windows the disk performance feels better than I remember the Sun boxes at Uni
>having...(without numbers though, this impression is completely
The 7850 is just as fast as the aic7870/7880 part except when you have
multiple drives in your system or are using a high number of tags per
device since the low number of SCBs kills performance.
>The IWILL mob (Taiwanese motherboard manufacturers) also do versions called
>P54TSW and P54TSW2 that have the relevant AIC- SCSI-Wide and Ultra controllers
>on them. Can't comment on how well they work, though.
These are known to work also.
Justin T. Gibbs
FreeBSD: Turning PCs into workstations