The 3ware 9550-SX series of SATA/300 RAID controller cards are supported by a driver included with version 2.6.14 and higher of the Linux kernel. 3ware has an open-soruce driver available for Linux 2.4 and older versions of Linux 2.6, and for those of us addicted to Slackware, they even have a Slackware 10.2 boot disk available. However, I wanted a kernel patch so I could easily compile my own kernel with the driver built in (not loaded as a module), so I decided to make one (download here).

To apply the patch:
cd /usr/src/linux
zcat /path/to/linux-2.4.x-3ware.patch.gz | patch -p1

Once the patch is applied, configure the kernel the way you normally would (probably make menuconfig) and under SCSI support, make sure SCSI support (CONFIG_SCSI) is turned on, then under SCSI low level drivers, you'll see an option for New 3ware Hardware ATA-RAID support (CONFIG_BLK_DEV_3W_9XXX_RAID) which you can enable (the patch does not enable it for you). Be sure to turn off the old option for 3ware Hardware ATA-RAID support (CONFIG_BLK_DEV_3W_XXXX_RAID).

To make a Slackware boot CD/DVD:

1. Make sure you're running the same kernel version as what's on your install CD
2. Copy the kernels/bare.i/config file from the Slackware CD to /usr/src/linux/.config
3. Configure the kernel as described above, and enable the new 3ware driver (I recommend not changing anything else)
4. Compile the kernel with make bzImage
5. Copy the Slackware install CD to your hard drive, and create a kernels/3ware.i directory
6. Copy /usr/src/linux/.config to the 3ware.i directory you just created, renaming it to config
7. Copy /usr/src/linux/arch/i386/boot/bzImage and /usr/src/linux/System.map to the same place
8. Compress the System.map file with gzip System.map
9. Edit isolinux/isolinux.cfg and set it to default to 3ware.i instead of bare.i
10. Follow the instructions in isolinux/README.TXT to make a .iso file and burn it

This patch is released under the GNU General Public License version 2, and comes with no warranty whatsoever. If your computer explodes and takes your new $490 RAID card with it, it's not my problem. However, if it works for you, let me know!