I want to set up a tape-back system to backup several PCs on a network.

I have : 
1. external SCSI tape-backup drive (HP SureStore DAT 24x6 autoloader)
2. a SCSI cable and a SCSI terminator. 

I'm planning to buy a  Dell PowerEdge 500SC server, 
and connect the tape-backup to it and operate that as my backup system.
These servers come with either a SCSI motherboard or an IDE motherboard
If I get the SCSI (more expensive) what else would I need to connect the
tape-drive to the server ?

In particular, would I still need a SCSI adapter 
(e.g. HP recommends Adaptec AHA 2940 Ultra Wide) ?
These adapters can cost $300+, so I dont want to buy it 
if its not needed with a server 
that has a SCSI motherboard.

Answer required :
  Is a SCSI adapter required with a Dell PowerEdge 500SC server 
  with a SCSI bus.?   (Yes/No with justification)

Related Links :
http://www.hp.com/cposupport/information_storage/support_doc/lpg51246.html

Hi yesdi,

The short answer is that you do not need to buy a separate SCSI
adapter if you buy the SCSI-enabled version of the Dell Poweredge
SC500 server.

You refer to the Dell PowerEdge 500SC as being available with an IDE
motherboard or a SCSI motherboard. However, according to the
specifications on the Dell website the SCSI option comes on a "Adaptec
39160 dual channel Ultra3 (Ultra160) SCSI card" rather than being on
the motherboard:

Dell - PowerEdge 500SC Product Details
http://www.dell.com/us/en/biz/products/model_pedsc_3_pedge_500sc.htm

To check this, I did a Google search for
dell 500sc "scsi motherboard"
and indeed no webpages were returned.

Hewlett-Packard's specifications for the DAT 24 describe its interface
as "single-ended narrow ultra 2 SCSI":

DAT 24 specifications
http://www.hp.com/products1/storage/products/tapebackup/dds_dat_drives/dds3_dat24/infolibrary/surestore_dat_24_tape_drive.pdf

Ultra-2 is an older SCSI standard and you certainly don't require the
leading-edge performance of the 39160 controller to support your tape
drive. But the Adaptec 39160 controller is specified to be
backward-compatible with ultra 2 SCSI devices and should be able to
handle your tape drive:

Adaptec SCSI Card 39160 Technical Specifications
http://www.adaptec.com/worldwide/support/techspecs.html?sess=no&prodkey=ASC-39160&cat=%2fProduct%2fASC-39160&fromarea=prod

The best option is to connect your tape drive to the 50-pin internal
connector on the 39160. You can do this neatly by purchasing a socket
mounted on a metal plate (like the ones attached to peripheral cards)
which has a flying lead that plugs into the 39160.

You can also use the external 68-pin connectors by purchasing a
68-to-50-pin adapter which will terminate the unused data lines. You
can get these, and just about any combination of SCSI
plug/socket/cable/adapter from suppliers such as RAM Electronics
Industries Inc, who have an extensive SCSI section on their website:
http://www.ramelectronics.net/html/scsi.html

Your alternative is to purchase the Adaptec AHA-2940 card. This
provides two benefits. Firstly, the external connector is a 50-pin
high-density socket which might match your existing cable. Secondly,
the combination of AHA-2940 and DAT24 is specifically recommended by
HP and it may be easier to get support for this combination.

But you don't need the AHA-2940. The 39160 offered by Dell can do the
job.

(Incidentally, I am running an HP DAT8 off a Dell 410 workstation with
motherboard SCSI, using the external 68-pin connector with an adapter,
and it has never missed a beat.)


Additional links:

The SCSI "Frequently Asked Questions" list
http://www.faqs.org/faqs/scsi-faq/

Adaptec "SCSI for Servers Comparison" page
http://www.adaptec.com/worldwide/product/prodfamilymatrix.html?sess=no&cat=%2fTechnology%2fSCSI%2fSCSI+for+Servers


Google search strategy:

dell poweredge 500sc server
://www.google.com/search?q=dell+poweredge+500sc+server

dell 500sc "scsi motherboard" (this search returned no results)
://www.google.com/search?q=dell+500sc+%22scsi+motherboard%22

dell 500sc "scsi adapter"
://www.google.com/search?q=dell+500sc+%22scsi+adapter%22

"adaptec 39160" specifications
://www.google.com/search?q=%22adaptec+39160%22+specifications


Regards,
eiffel-ga

Great answer eiffel !

Thanks a lot for the great answer !
That'll save me quite a bit of time and money.
Especially interesting to hear that you are 
running a somewhat similar setup.