From: david@dynamix.com (David L Jarvis)
Newsgroups: comp.unix.xenix.sco
Subject: Re: Adaptec 1740 modes.
Date: 29 Aug 92 12:30:35 GMT
Organization: SOFTWARE / DYNAMIX
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> I have an Adaptec 1740 installed in a Compaq 486/33M running SCO UNIX
> 3.2.4.  When the machine was initially configured, the Adaptec showed
> up in the power-up device list as 'type=ad'.  According to a list of
> adapter possibilities available when configuring SCSI devices, 'ad' is
> an Adaptec running in 154x or 164x mode.  'eiad' is a 174x Adaptec.

the 1740 has two operating modes; standard and enhanced  
the 'eiad' is the enhanced mode driver ... whatever mode driver you use
should correspond to the mode indicated in the eisa configuration for the
system

> So, why did the card show up as type 'ad' in the device list?  According

because it was installed that way!  :-)   you can install the standard
driver (ad) or the enhanced one (eiad) ... they are different ...

> to the Compaq system configuration, the card in that slot is identified
> as 'AHA1740'.  

the card *is* an AHA1740 ... running in standard mode (not enhanced) ...
the system configuration for the machine should have an option to set the
card into enhanced mode (at least thats the way it was for the last one I
did)

>               Is there any benefit to reconfiguring the UNIX setup so
> that the card is identified as type 'eiad' (ie. performance 
> improvement)?  

yes, there is a definite performance enhancement 
(see the doc that comes with the 1740)

>                If there is a benefit, how would one go about
> reconfiguring the system so that the card would be recognized as type
> 'eiad' on power-up?

1: login as root and cd to /etc/conf/cf.d
2: edit the file mscsi, change all occurences of ad to eiad
3: cd to /etc/conf/sdevice.d 
4: edit the file ad, change all occurences ad to eiad
5: link_unix
6: run your eisa configuration utilities to change the mode of the card

> Can I assume it would be foolish to think I could change the mode of the
> card without reinstalling UNIX, reconfiguring the hard drives, etc?

you can assume it ... but you'd be wrong  ;-)
the above should guide you thru the steps, but you can also give SCO
support a call (this is a popular one with them), or pick up a recent SCO
mag where they wrote up these very same instructions ...

> 
> Any and all input would be appreciated.  Thanks.

you're welcome ... good luck

#----------------------------------------------------------------------#
#          David L. Jarvis                 SOFTWARE  /                 #
#          david@dynamix.com                       /  DYNAMIX          #
#----------------------------------------------------------------------#
Newsgroups: comp.unix.xenix.sco