[comp.sys.atari.st] Daisy chaining SH204's

870646c@aucs.UUCP (barry comer) (11/19/87)

Keywords:SH204


I have a general question for all of the hackers out there, "Can you 
chain together the SH204 drives by installing an extra DMA socket on
the back of the case, providing that you wire it pin to pin with the
present socket?". I know that you can select which DMA device the drive
is by setting the dip switches inside. It just seems like common sense
to be able to this, but since when do common sense and computers mix?
later
Barry

leo@sunybcs.uucp (Leo Wilson) (11/20/87)

In article <570@aucs.UUCP> 870646c@aucs.UUCP (barry comer) writes:
>I have a general question for all of the hackers out there, "Can you 
>chain together the SH204 drives by installing an extra DMA socket on
>the back of the case, providing that you wire it pin to pin with the
>present socket?". I know that you can select which DMA device the drive
>is by setting the dip switches inside. It just seems like common sense

I believe it's the last section of the manual Atari distributes with the
SH204 that tells how to do this. The answer is 'Yes, it can be done!', but
I don't know the specifics. There are some pretty decent docs on how to
do this with the Supra drives, are the specifics the same?
-----
Leo E. Wilson 364 West Delavan Avenue Buffalo, NY 14213
(716)883-7573(leo@gort.cs.Buffalo.EDU)...!sunybcs![leow!]leo

exodus@uop.EDU (Freddy Kreuger) (11/21/87)

I wouldn't recommend buying another SH204...buy a 40 meg ST506 compatible
drive cheap from a mail-order house or so, make or buy the ribbon cables..
and add the drive to the existing adaptec 4000 controller already in the
SH204.....  Save some money and get a lot more storage out of it!!


G. Onufer

exodus@uop.EDU (G. Onufer) (11/21/87)

In article <5990@jade.BERKELEY.EDU>, c60a-2ae@web4e.berkeley.edu.BERKELEY.EDU (John Kawakami -O^O-,510d or 260E,6431816,6667734) writes:
> In article <570@aucs.UUCP> 870646c@aucs.UUCP (barry comer) writes:
> >I have a general question for all of the hackers out there, "Can you 
> >chain together the SH204 drives by installing an extra DMA socket on
> 
> But back to the question.  I think it's limited to two.  I recall
> something about the drive port pins: a drive select pin to address
> drive one and another for drive two.  The drive ports are just that,
> drive ports, not serial ports that "converse" with the devices.
> 
> HEY everybody, correct me if I'm wrong (hope I am.).
					  ^^^^^^^^^
Don't worry, you are.  Barry Comer is talking about daisy-chaining
SH204's, not the Tandon drives that come inside the SH204.  It is possible
to daisy-chain up to 8 of the SH204 by chaning the SCSI address of each.
(A 3-switch dipswitch == 2^3 combinations = 8).  Just make the right
cables and away you go....

But you did have the right idea... you add another physical drive inside
(well, to the internal controller anyways...be kinda hard to shove another
drive into that cabinet.)  the SH204..the Adaptec 4000 _can_ support two
hard drives.  

G. Onufer

dag@chinet.UUCP (11/21/87)

In article <5990@jade.BERKELEY.EDU> c60a-2ae@web4e.berkeley.edu.BERKELEY.EDU (John Kawakami -O^O-) writes:
>In article <570@aucs.UUCP> 870646c@aucs.UUCP (barry comer) writes:
>>I have a general question for all of the hackers out there, "Can you 
>>chain together the SH204 drives by installing an extra DMA socket on
>>the back of the case, providing that you wire it pin to pin with the
>>present socket?".  [some stuff deleted]
>>later
>>Barry
[John KaWaKaMi's initial comments deleted...]
>But back to the question.  I think it's limited to two.  I recall
>something about the drive port pins: a drive select pin to address
>drive one and another for drive two.  The drive ports are just that,
>drive ports, not serial ports that "converse" with the devices.
>
>HEY everybody, correct me if I'm wrong (hope I am.).
>
>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>| JoHn KaWaKaMi alias spectacle -O^O- alias c60a-2ae@widow.berkley.edu      |
>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


Okay, I'm not everybody, but I will take a stab at it.

			**********************
			*** You are wrong. ***
			**********************

The floppy connection is limited to two drives, and though the data comes
in through the DMA chip from the floppy, this is not the DMA port.  The
DMA port allows connection of a fairly large number of devices (8 or 16?)

I've spoken in the past with some people at Atari about connecting
a second DMA device, and they said that the extender would have to
be buffered since the DMA chip cannot handle much more load than the
SH204 puts on it.  I believe that several vendors now sell drives/controllers
which have DMA daisy chain plug.

Include in this number ICD, from Rockford, IL.  Maybe Supra now sells one,
and I believe that even Atari has shown a drive with this feature.

You can, however, add a second drive to the controller inside the SH204.
I don't have details right here.

These						Mild Flame....
     Lines					The line counter was added
          Are					to decrease the wasted
             Added				reposted trash, but when
                  To				a reply does not make sense
                    Defeat			without some quoted stuff,
                          The			it often means more trash
                             Dreaded		is posted to post short
                                    Line	answers...
                                        Counter	....Flame off
                                               !
-- 
					Daniel A. Glasser
----------------------------------------+----------------------------
Cheese is not a discipline!		| ...!ihnp4!chinet!dag
					| ...!ihnp4!mwc!gorgon!dag
					| ...!ihnp4!chinet!gorgon!dag
Disclaimer: I assume full responsibility for my opinions.
            If my employer knew of some of them, I'd be unemployed.

long@sask.UUCP (Warren Long) (11/27/87)

In article <6654@sunybcs.UUCP>, leo@sunybcs.uucp (Leo Wilson) writes:
> In article <570@aucs.UUCP> 870646c@aucs.UUCP (barry comer) writes:
> >I have a general question for all of the hackers out there, "Can you 
> >chain together the SH204 drives by installing an extra DMA socket on
> >the back of the case, providing that you wire it pin to pin with the

I have seen ads from Supra advertising cables to hook two
harddrives to an ST.  Can anyone comment?  Anyone used these??

Warren

-- 
=-=-=-=-=-Warren Long at University of Saskatchewan, Canada-=-=-=-=-
Home: 78 Carleton Dr.,Saskatoon, Sasakatchewan, S7H 3N6
Phone: (306)-955-1237
=-=-=-=-=-U-Email: ...!ihnp4!alberta!sask!long     -=-=-=-=-=-=-=-=-