Brendan Horan Avatar

I've got some odd hardware.. One of the weirdest boxes would be the IBM power4+ 275 workstation. It's over build in typical IBM fashion and it takes about 15mins to turn on.  It checks every part of the system in every detail. nice work

Specs on mire are :

  • Single dual Power4+ @1.4ghz (single chip dual core)
  • 4gb of ram
  • 2x 36gb SCSI HDD
  • floppy and tape video ect..

See here for more info, Wiki and IBM You can find all the manuals and service guides hear

I wanted to add SCSI tape drive (DDS4) into the system. Should be easy right? .. ah no this is IBM there's a special cable for everything! IBM's doco make no mention of it apart from a part number.

That's not to helpful for me. I need to know the power pin out of the odd power connector (everything on this box is ODD!) The SCSI plug is easy, it's just a normal 68pin  plug we can just chop up a bit of old internal UW SCSI cable.

Funny enough the power plug on the back of the Media bay looks just like the 4pin P4 power plug we see on pretty much every ATX power supply now. It also fits perfectly. Now its just a matter of  finding the voltage for each pin and wire that into a molex plug to connect to the tape drive.

Maybe a picture would make this easier :- Hear you can see the power plug on the back of the media board, the P4 power plug clips right into the socket! plug voltages

So now we have the voltages of the plug its quite simple to wire this into a molex plug like the below image :- i done power The above cable is plugged into the media board then into my tape drive, just a normal 4 pin molex power plug and a standard p4 power plug. Clips into the socket perfect no pin changes hacks ect..

Now will it work? I set up my tape drive and used the following command under AIX  :

# lsdev -Cctape

This should return something like the following :

"rmt0 Available 06-12-09-3,0 Other SCSI Tape Drive"

From the above we can see its found the tape at SCSI ID 3 and LUN 0.

Test it with the following command :

# dd if=/dev/zero of=/dev/rmt0 bs=256k count=4096

The above writes 1gb of data in 256k blocks to the tape drive. This should show no errors or any real status message.

You can view all the images of the mod on my flicker