On the SPARC Netra T1, there is an option to have a CD-ROM installed in the machine. The front of the CD-ROM is visible through the front panel of the machine when it is rack-mounted.
The original model of CD-ROM drive that came in the Sun Netra T1
(model 105) was the Toshiba
XM-1702B. (This was later updated with a Toshiba XM-7002BC drive,
in April 2000. This drive was then replaced by the Teac CD-224E drive
in December 2001.) But these changes are irrelevant to this
discussion.) It's a slimline
ATAPI drive, originally designed
for the tight space constraints of a portable. To connect this ATAPI
drive to the Netra T1, a device known as a paddle-board
is used. The
paddle-board is a combination of cable and circuit board. (circuit board back)(circuit board front) The Sun part
number for just the paddle-board appears to be 540-4229.
Note, however, there is a small bracket that attaches to the back of
the CD-ROM drive to hold the unit into the chassis. I don't know where
you can buy one of those, although you could assemble one with little
difficult from some sheet metal and a pair of pliers.
On some computer motherboards, the mode for an IDE/ATAPI device is
selected between the MASTER and SLAVE
settings, using a mechanism known as cable select
. Simply put,
cable select signaling shorts the cable select
signal in the IDE
cable to ground to indicate a MASTER device and leaves the
cable select pin floating (i.e., not connected to anything) to indicate
that a device is SLAVE.
Experimentation with the paddle-board in a Netra T1 105 shows that
the cable select pin is left floating. A normal
ATAPI device
that supports cable select and is connected to the paddle-board will be
automatically configured as a slave device. Unfortunately, the Sparc's
boot-prom doesn't seem to find any slave ATAPI devices, only master
devices.
The Sun supplied Toshiba 1702B, on the other hand, doesn't appear to
support cable select, but rather uses that pin to select
MASTER or SLAVE on the device directly. Note
that using this pin to select MASTER or SLAVE is subtly different than
supporting cable select! For example, using a completely stock
paddle-board, and a completely stock Toshiba CD-ROM, probing from the
PROM shows this:
Executing last command: probe-ide-all
/pci@1f,0/pci@1/pci@1/ide@e
Device 0 ( Primary Master )
Not Present
Device 1 ( Primary Slave )
Not Present
Device 2 ( Secondary Master )
Removable ATAPI Model: TOSHIBA CD-ROM XM-7002Bc
Device 3 ( Secondary Slave )
Not Present
Conveniently, Sun left solder pads on the paddle-board front, labeled as R0301,
which can be used to force the cable select signal to ground. Soldering
a wire across these pads (picture
1) (picture 2) will pull
the cable select line to ground, thereby making a normal ATAPI drive
operate as MASTER. In the picture, you will notice there is also a
nearby set of solder pads labeled R0302. I have no idea what they are
used for, but on the cables I examined, nothing was connected to the
solder pads.
After the R0301 solder pads on the paddle-board have been joined together a normal ATAPI device, like a Toshiba SD-R6372 DVD +/- RW drive can be attached to the machine and probed successfully.
Executing last command: probe-ide-all
/pci@1f,0/pci@1/pci@1/ide@e
Device 0 ( Primary Master )
Not Present
Device 1 ( Primary Slave )
Not Present
Device 2 ( Secondary Master )
Removable ATAPI Model: TOSHIBA ODD-DVD SD-R6372
Device 3 ( Secondary Slave )
Not Present
After modification to the paddle-board in this manner, the Sun
supplied CD-ROM will no longer probe properly on the machine. It would
appear that Sun's slim-line CD-ROM drives are configured to treat the
cable select line in the reverse of normal cable select rules. Namely,
that a floating line should be MASTER and a grounded line
should be SLAVE. However, cutting or removing the
installed wire will return the paddle-board to its original state, so
that a Sun supplied CD-ROM will work in the machine again.
Once the DVD +/- RW drive has been installed, it can be used in any
of the normal methods to read or write CD-ROM and DVD-ROM drives. E.g.
cdrw or cdrecord under Solaris,
cdrecord under BSD/OS.
Back to the page of Not So Frequently Asked Questions.
Kurt J. Lidl