Currently the &architecture; port supports several types of Sparc systems. The most common identifiers for Sparc systems are sun4, sun4c, sun4m, sun4d and sun4u. Currently we do not support very old sun4 hardware. However, the other systems are supported. Sun4d has been tested the least of these, so expect possible problems with regard to the kernel stability. Sun4c and Sun4m, the most common of the older Sparc hardware, includes such systems as SparcStation 1, 1+, IPC, IPX and the SparcStation LX, 5, 10, and 20, respectively. The UltraSPARC class systems fall under the sun4u identifier, and are supported using the sun4u set of install images. Some systems that fall under these supported identifiers are known to not be supported. Known unsupported systems are the AP1000 multicomputer and the Tadpole Sparcbook 1. See the Linux for SPARCProcessors FAQ for complete information. Some older Sun workstations, notably the Sun IPX and Sun IPC have memory banks located at fixed locations in physical memory. Thus if the banks are not filled gaps will exist in the physical memory space. The Linux installation requires a contiguous memory block into which to load the kernel and the initial RAMdisk. If this is not available a Data Access Exception will result. Thus you must configure the memory so that the lowest memory block is contiguous for at least 8Mb. In the IPX and IPC cited above, memory banks are mapped in at 16Mb boundaries. In effect this means that you must have a sufficiently large SIMM in bank zero to hold the kernel and RAMdisk. In this case 4Mb is not sufficient. Example: In a Sun IPX you have a 16Mb SIMM and a 4Mb SIMM. There are four SIMM banks (0,1,2,3). [Bank zero is that furthest away from the SBUS connectors]. You must therefore install the 16Mb SIMM in bank 0; it is then recommended to install the 4Mb SIMM in bank 2. Especially in the case of older Sun workstations, it is very common for there to be an onboard framebuffer which has been superseded (for example the bwtwo on a sun IPC), and an SBUS card containing a later probably accelerated buffer is then plugged in to an SBUS slot. Under Solaris/SunOS this causes no problems because both cards are initialized. However with Linux this can cause a problem, in that the boot PROM monitor may display its output on this additional card; however the linux kernel boot messages may then be directed to the original on board framebuffer, leaving no error messages on the screen, with the machine apparently stuck loading the RAMdisk. To avoid this problem, connect the monitor (if required) to the video card in the lowest numbered SBUS slot (on motherboard card counts as below external slots). Alternatively it is possible to use a serial console.