(sketch of an IBM 850)IBM PowerPC "Carolina" systems

This page contains some information and patches for running Linux on IBM PowerPC machines based on the "Carolina" motherboard. This includes Personal Computer Power Series 850/830 machines (model 6070 and 6050 desktops) , and the 7248 series 43P machines (not the later 7043 series). It also includes a little information on the Power Series 850 Thinkpad

The original of this page is at http://www.amberdata.demon.co.uk/carolina/. There is also a mirror at http://www.abcompcons.com/carolina/.


What is it?

The "Carolina" motherboard is the basis for some of the older desktop PowerPC systems made by IBM. It was used in the Personal Computer Power Series 830 and 850 machines, which were probably meant to run Windows NT. These machines have IBM type numbers 6050 and 6070. It also appears in the early RS/6000 43P machines with type number 7248, which would have been sold to run AIX. (Almost all IBM machines have a 4 digit type number - generally those starting with "6" seem to indicate desktop PCs, and those with "7" indicate RS/6000 machines of some sort).

It is a fairly normal PReP-compliant PCI/ISA system board with the slots on a riser card. All the systems I've seen have PowerPC 604 chips running from 100 to 133MHz, although I believe earlier systems may have used the 601 chip instead. It includes the usual 2 IDE channels, floppy, parallel and 2 serial ports. It also has a built-in AMD 79C970A PCnet/PCI II ethernet, an S3 Vision 864 video controller with an S3 SDAC and 2M of video ram (an "E15" in AIX parlance), a Crystal CS4232 audio controller, and the boards built for the 7248 boxes have an NCR 53c810 SCSI host adapter as well. (This components for this were simply left off boards for the 6050/6070 - if you look at a 6070 board, just in front and to the left of the riser card slot you will see space for two missing chips (the larger one is the ncr53c810) and along the right hand edge of the riser slot is a missing 50 pin ribbon connector with "SCSI" printed next to it on the silkscreen).

Common extra cards in the machines include the "S15" graphics adapter (actually a Diamond Viper Pro minus the bios chip, which was based on the Weitek Power 9100/9130 chipset with an IBM RGB525 ramdac), the GXT150P graphics adaptor (all-IBM card, I think with 3D support), a PCI scsi host adapter card with an NCR 53c825 chip, and various random token ring and ethernet cards (usually ISA).

What works under Linux

There are a few issues with these machines under Linux. In particular, vanilla 2.2 kernels will probably fail to boot sucessfully at all. You will probably need a modified kernel, which you can create using the patches below. These are against 2.2.15+ kernels. I do not recommend trying to use anything earlier. 2.4 kernels currently almost work if you apply the patch below but there are probably still a few oddnesses to remove yet.

More details:

What doesn't work under Linux

With standard 2.2 or a recent 2.4 snapshot and the patches below, pretty much all the basic hardware should work fine. Things that don't are the better graphics adapters, and token ring cards. The SCSI host adapter appears to work fine.

PCI adapters other than those which were sold as options by IBM generally won't work at all with 2.2. This is because the firmware only appears to initialize cards it recognizes, leaving the ones it doesn't with all the PCI config space set to 0s. With some cards the machine simply won't even boot. For those where it does (eg Matrox G200 cards and Intel 82557 ethernet cards (eepro100 driver)) this problem should be solved by using 2.4, although the drivers may need fixing because the PReP architecture has an offset of 0xC0000000 when accessing memory on cards which most drivers don't know about.




Last Update: Sun Mar 25 18:36:06 BST 2001
Email: David Monro <davidm@amberdata.demon.co.uk>
Homepage: http://www.amberdata.demon.co.uk/personal