UDC CARD: daisy-chaining 3 drives?

[sebugg@presby.edu (Stephen Buggie)]

sebugg@presby.edu                                       Aug 22, 1993

         DAISY-CHAINING THREE DISK DRIVES FROM THE LASER UDC CARD
                  TO VACATE A SLOT:  CAN IT BE DONE?

I am trying to free up a slot in my fully-loaded IIe in order that my
Apple high-speed SCSI card can find a berth somewhere.  Recently, I asked
readers whether the super serial card now in slot 1 could be moved to
slot 3, the only vacant slot.  Four readers replied via e-mail and they
all stated that the 80 col firmware in the aux slot card will interfere;
therefore my plan will not work.   I tried again to operate the mouse
card from slot 3, but it won't respond if placed there.

What next?  For review, here is the present slot configuration:

                     Platinum IIe: Present Slot Assignments
                     ======================================
SLOT #              INTERFACE CARD                      OTHER ACCESSORIES
------       ------------------------------------------|----------------
  1          super serial card, connected to printer   |  8 MHz ZIP CHIP
  2          Apple mouse card                          |
  3          (vacant slot!)                            |  AE heavy-duty
  4          AE Datalink 2400 modem card               |  power supply
  5          Laser UDC card, with AE 800K disk drive   |
  6          Apple Disk ][ card, with two Disk ]['s    |  No-Slot Clock
  7          AE Ramfactor memory card with 768K RAM    |
aux slot     Sequential Systems 1024K ram/80 col card  |

Note that slot 5 houses the Laser UDC card, which presently runs just one
card: the AE 800K 3.5" drive.  It was always (18 months) worked well there
and I recommend the UDC card highly.

The instructions for the UDC card state that it is capable of running up to
FOUR disk drives from its two on-board db-19 drive ports.   Aha ..........!
Yes, you guessed it ..... why not operate all three of my floppies (one 3.5
AE, plus two Disk ][ drives) from the UDC card?  This would then free up
either slot 5 or slot 6!   I have several Disk ][ drives but also one
platinum Apple 5.25" drive with its daisy-chain port.  The AE 3.5 also has
a daisy-chain port.

POSSIBLE ARRANGEMENTS:

EITHER:

UDC PORT ONE---->AE 3.5 ------> Apple 5.25 -----> Disk ][
UDC PORT TWO   (left vacant)

OR:

UDC PORT ONE----> AE 3.5 -----> Disk ][
UDC PORT TWO----> Disk ][


QUESTION: I dont want to overwork the UDC card: these cards are scarce and
are no longer produced.  Would it shorten the life of the UDC card to
make it power three drives rather than one?

Also, does the Disk ][ drive consume more power than the Apple 5.25 or the
Disk IIc drive?  I have one each of the latter two models and would use them
if that meant less electrical stress on the UDC card.  If it doesnt matter
then I would prefer to use the Disk ][ drives.

COMPLICATION:  The UDC manual states that when three drives are connected
in a daisy-chain arrangement, then one of the drives will be assigned as
"Slot 2, Drive 1."  Well, slot 2 is filled already, either by my modem or
my mouse card!  Does this phantom-slot assignment mean that I most remove
a real card from slot 2?   If so, then I am back to square one (!).

Advice will be appreciated!   If I receive e-mail responses, then I will
summarize them briefly and report the results back to this net.  sebugg

 **=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=**
 ** Stephen Buggie, 410 Chestnut St., Clinton SC 29325    Apple IIe/IIc **
 ** sebugg@presby.edu                 voice: (803) 833-8337 or 833-1632 **
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