Questions on SCSI device interfacing...

[Rusty Hodge]

In article <433 at icus.UUCP>, lenny at icus.UUCP (Lenny Tropiano) writes:
> With the recent announcement by IDT Systems to support SCSI devices on
> the AT&T 3B1, some questions have come up in my mind.
> The questions that I have are:
> 
>    1.   Do I have to buy a special interface when I purchase SCSI devices,
> 	or if the device says it is SCSI compatible will it include
> 	the necessary hardware to just hook up the 50-pin Centronics SCSI
> 	cable directly?

A raw SCSI drive usually has a 50-pin header connection.  The standard SCSI
connection is a 50-pin Centronics.  The Macintosh folks use a DB-25.  Don't
ask me to explain, but it works.  I think that IDT is going to use a DB-25
a la Macintosh.  You could just buy any Mac hard drive system and plug it in.
Or make a cable and use a raw drive.

>    2.   How do you hook a multiple of devices (up to 7) to the SCSI host
> 	adapter?  Do you just need to daisy-chain them along and give
> 	each a particular identification in the device driver?

You just daisy-chain them.  The drive has a Device ID jumper on it.  There are
8 ids, the host interface is one of them.

>    3.   Do SCSI devices cost MORE or LESS than other devices?  In 
> 	particular, tape drives and hard drives.

Embedded-SCSI drives cost about 10% more than ther drives sometimes.  Some
drives (Seagate ST-277N, 60mb 40ms) are very competitive: $450 or less.

A SCSI CDC Wren 300mb 16.5ms drive should be able to be found for just over
$2000.  A 150mb version for under $1300.


You can buy a complete CMS Mac External 140mb system for under $1500.
This includes a case, power supply and 1-year warranty.  There are plenty
of other suppliers to choose from (Like Micah, right Larry? :->).

Well, this is exciting.  I've finally answered a question from Lenny.
It feels good to answer rather than ask for a change! :->

-- 

Rusty Hodge, HCR Inc, 1588 N. Batavia St. Orange, CA 92667      (714) 974-6300
rusty at hodge.cts.com [uunet vdelta crash]!hodge!rusty        FAX (714) 921-8038