Question about SCSI disk mode

[coius]

If I were to hook one machine up to another. say two powerbooks, one booted from internal drive, and the second booted into SCSI disk mode, would the CD/DVD-ROM from the SCSI Disk mode'd powerbook show up on the other machine? Just wondering, because I know that FWTDM does that. Any drive in the machine with FWTDM on, would show up on the desktop of the machine that it was attached to. Including optical drives.

[wood_e]

I'm pretty sure it would since it would be on the SCSI bus of the powerbook.

[gobabushka]

just try it and see what happens

[coius]

just try it and see what happens

I will tomorrow. I just have to hook the two PowerBooks up to see. it's just that the cable for one of them is short, and the other has to have the adapter on it to turn it into SCSI disk mode. It's a very tight fit if you use them. The one that is the cable is an HDI-30 (or whatever it is) that goes to centronics female adapter. the other adapter, is an HDI-30 -> Centronics Male. I will let you guys know the outcome to it!

[coius]

I'm pretty sure it would since it would be on the SCSI bus of the powerbook.

These are two powerbook G3s, they are IDE. I think it uses a bridge for it. But i don't know if they are two ide channels, or one. and if they are two, are they both connected to the same bridge?

[Mac128]

I'm pretty sure it would since it would be on the SCSI bus of the powerbook.

These are two powerbook G3s, they are IDE. I think it uses a bridge for it. But i don't know if they are two ide channels, or one. and if they are two, are they both connected to the same bridge?

Apple implemented IDE over SCSI via translation by the ATA driver. So, yes, both PowerBooks know how to translate the SCSI DIsk Mode commands to the internal IDE drives. I trust you figured this out given the date?

Also, two PowerBooks would need to be joined with a powered terminator in SCSI disk mode, unless the G3 Series provided termination Power – AND THEY DO: http://docs.info.apple.com/article.html?artnum=6159 The original PowerBooks even needed terminators with the desktops.

Since the 140, 145, 150 & 170 did not provide for SCSI Disk Mode, I was wondering if anyone remembered the procedure for hooking two desktops together in SCSI Disk Mode, which should work on these PowerBooks as well?

I think it had something to do with interrupting the desktop startup process so that power was provide to the SCSI bus and hard drive, but no System tried to grab the resources or conflicted with another System ID. With a PowerBook, the drive conflict could be fixed by changing the PowerBook's drive ID with the Portable Control Panel, but on a desktop, you had to make sure one of the internal drives was physically set to a different SCSI ID.

Even though the 140, 145, 150 & 170 could not enable SCSI Disk Mode, could they use the Portable Control Panel to change their drive's SCSI ID?

I did a Google search but was surprised to find nothing about this process which I used to do back in the day. Anybody know a source?

[Bunsen]

One gotcha is that the firmware for SCSI Disk Mode only recognised hard drives up to 6GB. I know that was true in the 1400, and I have a vague thought that it is true in the G3s as well. If so, attempts to access the HD over SCSI can result in data corruption and/or drive corruption.

[Franklinstein]

One gotcha is that the firmware for SCSI Disk Mode only recognised hard drives up to 6GB.

I thought the limitation was only 4GB...

Anyway, I've circumvented that little flaw by partitioning a larger drive: a <4GB partition at the very front of the drive, with the remaining partitioned however.

SCSI Disk Mode works fine accessing the <4GB partition, but don't try accessing the other ones or any partition beyond the first 4GB of the disk, or it won't work right (data corruption). This was how I installed OS X on my 2400c, and it worked splendidly.

[Mac128]

One gotcha is that the firmware for SCSI Disk Mode only recognised hard drives up to 6GB. I know that was true in the 1400, and I have a vague thought that it is true in the G3s as well. If so, attempts to access the HD over SCSI can result in data corruption and/or drive corruption.

You're talking about this: http://developer.apple.com/technotes/tn/tn1116.html#4GB

Which indicates the problem was fixed in the G3s.