|(c) 2003 Simtec Electronics (VS)
|$Id: EB7500ATX-debian.html 197 2003-02-03 01:38:11Z vince $
To install Debian 3.0 (revisions prior to 2) on the Simtec EB7500ATX boards the Simtec Debian installer CD is required. This CD contains a specially built Debian install image.
General instructions on ABLE can be found in the ABLE user guide available from the Simtec Website.
Installation is started with an ABLE shell script from the CD "(cd0)install.sh", this script simply sets the command line, loads the Linux kernel, loads the install ram disc and starts the install.
The installation will proceed as normal for a Debian ARM install, the disc should be used to install the system until the base system files are required. The official Debian ARM disc 1 should be used from that point onwards.
Once the install is complete the system will reboot, the system may be configured to boot directly into the OS by setting the nvram parameter boot-cmd e.g. "nvset boot-cmd (hd0)vmlinuz root=/dev/hda1" and a non-zero boot timeout using "nvset boot-time 1". Remember to use nvsave to save the parameters.
The minimum memory requirements to install Debian on this system is 24Mb. Due to constraints on the size of physical memory bank allocations and the Linux zone allocator that 32Mb must be fitted either as a single 32Mb Simm or as two 16Mb Simms for a successful installation.
The Debian install requires an additional 8Mb of RAM for its root ram disc hence the requirement for 24Mb (the absolute minimum is 16Mb for a usable system).
Due to the physical arrangement of memory on a 7500FE system memory is split into four banks, each simm may carry memory which may occupy two of the four banks. The memory allocator in ARM Linux 2.4 is currently limited in its handling of these banks of memory. This results in the distribution of memory across these banks changing the behavior of Linux when dealing with large initial RAM discs (such as the install image).
Once installed the system will run in 16Mb which may be arranged in any order. Simtec have tested numerous permutations from 4Mb in each bank to 16Mb in a single bank, all such combinations work provided a large initial RAM disc is not required.
It has been noted that some discs that have been used for other operating systems prior to installing Debian may confuse the partitioning tool, this may be solved with the following procedure:
ABLE versions prior to 1.30 should be avoided and will probably fail to install.
There are also issues with versions prior 1.40 with certain memory configurations the Linux kernel will fail to start and the user will be returned to the command prompt. This is fixed in versions after 1.40.