Powerbook G3 PDQ : Prevent boot from SCSI (HDI30)

4 posts / 0 new
Last post
Last seen: 12 months 3 days ago
Joined: Apr 17 2022 - 12:26
Posts: 71
Powerbook G3 PDQ : Prevent boot from SCSI (HDI30)



I've been asking the same question on 68KMLA and we haven't found a solution.


I'm trying to connect a G3 PDQ to a PB100 thru Target Mode.

On the PB100 end, all is good. I've got the proper connectors etc


On the G3 PDQ end, the problem I have is that the G3 wants to boot from SCSI whatever I do.

Hitting "D" does not help (does nothing)


A lot of documentation about open firmware and keys to hold during boot time is incorrect on the internet.

This is an old world mac, I can enter open firwamre ( ctrl/opt/O/F) but the command "multi-boot" does not exist.

Holding "D" doesn't seem to exist


There seems to be no way to prevent a G3 to boot from SCSI if you ever connect it to a SCSI drive, which makes no sense to me...


Any help/advice appreciated.

Last seen: 3 hours 46 min ago
Joined: Feb 27 2021 - 18:59
Posts: 551
no boot picker

The boot picker and its keyboard commands don't exist on Old World machines. You can hold the mouse key to skip the default boot device.

You can also use a boot Disk Tools floppy to run the Startup Disk utility to select the volume to boot from, which should solve the issue you mentioned.

Does your HDI-30 adapter for the PB100 have all 30 pins ( SCSI Disk Adapter M2539-)? Were you able to set the target SCSI ID on the PB100?

Last seen: 12 months 3 days ago
Joined: Apr 17 2022 - 12:26
Posts: 71
Yes, on the PB100 side I have

Yes, on the PB100 side I have a dock/scsi adapter with a switch, and it has 30 pins (goes to DB25)


However it is not really documented how to connect a powerbook (hdi30) to another powerbook (hdi30).


What I did is to have a HDI30 with 29 pins on the PDQ side ( a "regular" hdi30 to DB254), then a small DB25 cable , then a hdi30 scsi/dock on the PB100 side 


The switch makes the PB100 automatically go into target mode (no need to hit T or anything). I can set the scsi ID on the PB100.


However i'm really stuck with the PDQ trying to boot systematriclaly from the attached scsi drive, that's not what I want, i'd like it to boot on its own internal IDE drive, with the scsi disk auto mounted on the desktop. This is what is supposed to happen...


I was only able to "hot plug" the PB100 but I know this is not recommended ( I booted the pdq, then only booted the pb100 in target mode, then did a rescan of ports on the pdq, the scsi appears, and I can "mount" it manually in the dick utilities) However not only is this probably dangerous but also it's not really working like it should, the peripherals appear in the PDQ with their actual SCSI ID (not the "fake" target ID). There are also oddities wihen using a bluescsi. (Again I know this is not how I'm supposed to use it.)


My PDQ does not have a floppy drive  (damn I really need one !!) but ... your idea is the best I had so far.  So thanks for that !

Maybe I can make me a boot ZIP (I've got a VST Zip100 drive) or a boot CDROM instead (this I've got too)

Tom Owad's picture
Last seen: 7 hours 39 min ago
Joined: Dec 16 2003 - 15:14
Posts: 3378
Can you un-bless the PB100's

Can you un-bless the PB100's system folder before you attach it, then re-bless it when you're done?

There are utilities for that, or:

Boot the PB100. Drag Finder out of System Folder. Shut down. Attach to the G3, boot, do your stuff. Put Finder back in the System Folder. When you do that, the System Folder should show the system icon again instead of a generic folder icon. if it doesn't, boot the PB100 off floppy and put Finder back in the System folder.

IIRC, you might need to open and close the System Folder to detect that Finder has been returned.

Log in or register to post comments