Mike's PCjr Page

While rooting around in some boxes of old gear today, I ran across a couple of hard drives pulled from PCs many moons ago. One is a Maxtor 7546AT, a 540MB IDE drive, with a manufacture date of 12/1994. The other is a Western Digital WD300, a 30GB Enhanced IDE, manufacture date of 11/2000.

It'd be interesting to hook them up to something to see if there's anything on them worth copying off. In the same box was a 40-conductor ribbon cable that in theory would allow both drives to be plugged into the jrIDE's IDE pinout simultaneously. The only other thing is that I'd need to find a way to power the drives (I do have some loose power plugs with red-black-yellow wires). So:

-- Do either or both of these seem to be of the right type that the jrIDE BIOS would probably recognize them?

-- If I attach them at the same time with the same ribbon cable, would the jrIDE BIOS probably recognize them as drives 0 and 1 and make them usable simultaneously?

-- Anything else I should think about before trying this out?

But wait, there's more -- two more drives with 40-pin connectors unearthed:

-- Western Digital Caviar 31600, 1624.6 MB IDE, manufacture date 2/1996

-- Seagate ST34311A, 4311 MB, manufacture date not clear

The last of these looks like it might have been exposed to the elements somewhat, so I would not be surprised if it doesn't start up at all.

The BIOS does support two drives. I've tested this with two DOMs, but never used spinning disks.
viewtopic.php?f=1&t=180&p=1934&hilit=both#p1934

Attach both on the same cable. The drives need to be jumpered correctly- one for master, one for slave. It doesn't matter which one is master or which one is at the end of the cable. The 540MB drive is the least likely to work- it may only support CHS addressing. Good luck!

Hargle wrote:The drives need to be jumpered correctly- one for master, one for slave. It doesn't matter which one is master or which one is at the end of the cable. The 540MB drive is the least likely to work- it may only support CHS addressing. Good luck!

Thanks. I'll need to hunt down the instructions for each one to see about getting master-slave set right. As a starting point I'll probably just connect each disk drive by itself to the jrIDE and boot with a floppy to see if the drive appears to work.

The BIOS does support two drives. I've tested this with two DOMs

With two DOM's, am I guessing correctly that there's no need to set them differently (master/slave, etc)? If some setting is required, how do you do it?

DOMs are no different than normal HDDs with regard to master/slave. That's an ATA specification requirement, so all devices that attach to a 40/44 pin cable must have that capability.

If you look in this pic
https://www.waste.org/~winkles/idejr_dom.jpg
Just above the "6" on the dipswitch, in the lower right corner of the DOM itself is a small jumper- that's the master/slave setting which you can see on the PCB silkscreen.

Now that you mention it, I do see a tiny switch on my KingSpec DOM, and a jumper on my CF-to-IDE adapter. Thanks!

Yeah, it makes sense that the ATA<->CF adapter is where the master slave setting should be and not on the CF itself.
The switch might be a write protect.

Well, this is interesting. I found a little 12v/5v power supply, power cable and 40-pin ribbon cable, and set things up to try each of the four hard drives mentioned above with the jrIDE.

Not too surprisingly, three of the four drives were unrecognized by the jrIDE (and, in fact, generally made alarming-sounding noises when powered).

However, the other drive, the 1624MB Western Digital Caviar 31600 from 1996, showed up as drive 1. I'm not sure why it was that rather than drive 0, I guess maybe it had its slave jumper set?

I was hoping this would mean it would magically appear as, say, drive D: (C: being assigned to the 3.5" backpack), but none of the drive letters I tried allowed me to access the drive. Sorry to be in remedial mode here, but is there a command I need to execute to assign the drive a letter? I wouldn't think I'd want to use fdisk -- doesn't that wipe it? I actually want to see what's on it, if it's still readable.

You can simply view the detected drive geometry and partition table by running fdisk without options and selecting menu item '4' - Display partition table information.