Running Linrad under different Linux distributionsLinrad can run on elderly computers with small memory if the bandwidth of the input signal is small. A 66 MHz Pentium is sufficient to process the output from a conventional SSB receiver. Linrad can probably run even on a fast 486, but installing Linux and getting the sound working is not easy. Distributions with the 2.2.xx kernel are old enough to fit in old Pentium computers but e.g. Red Hat 9 with the 2.4.20 kernel needs at least 64 megabytes of ram and can not be installed in PI class computers that typically have 16 megabytes of memory.
Linrad should compile under all Linux distributions. Some distributions have sound systems that work automatically, others require some knowledge to be set up properly and some (very old ones) require a Linux guru. OSS is very easy to install if one can find the right OSS version that fits old distributions or if the kernel headers are correctly set-up so the oss modules can be compiled locally. ALSA is more difficult, I have never installed it from scratch myself, but it is included in some distributions and then it easy to use. ALSA and legacy sound are configured with sndconfig while soundconf is used for OSS.
Table 1 shows sucess and failure of installing modules for svgalib, OSS and SDR-14. None of these modules is needed for using Linrad under X11 or as root with svgalib provided that the default sound system was installed properly.
Generally older distribytions fit older computers. If you want to use Linrad on an old Pentium computer with 16 megabyte memory it is not possible to install from the distribution CDs of modern distributions. There are exceptions however, Debian ETCH netinstall works fine on a Pentium 100 MHz with 16 megabyte and it actually works better than RedHat 6.1 in case the CPU is heavily loaded by high processing bandwidths. The scheduling between the different threads in the 2.6 kernel is better than in the 2.2 kernel. It is however much easier for a newcomer to install RedHat 6.1 so that is what I recommend for old computers. For a Pentium MMX with 64 megabytes I think Mandrake 8.0 is the most convenient distribution.
If you are a newcomer it may be a good idea to look for a Linux distribution with OK in the columns SDR-14, svgalib and X11. This will allow you to use an SDR-14 and to choose between svgalib and X11 for the graphics.
Note that modern distributions may require that kernel-headers are downloaded from the Internet. Usually it is not possible to find the headers for the kernel on the distribution CD on the Internet, there are more modern kernels and header-files belonging to them only. Upgrading the kernel may work smoothly but there is a risk that problems are encountered. Sometimes an upgrade might change the gcc version causing problems with modules that are compiled with the wrong gcc version.
Table 1 In the svgalib column NoHelper means that the NoHelper option must be enabled in libvga.config. ALT means that Makefile.alt must be used to compile svgalib_helper (or alternatively NoHelper can be used.) The devices listed in the mouse columns is the device that has to be specified with mdev in libvga.config. Sometimes different for different mice. Default means that no mdev specification is needed in libvga.config. oss395d.tgz ( 2078721 bytes ) can be downloaded from the link in the table, the other oss versions can be downloaded from opensound.com. The svgalib version is svgalib-1.9.25 with a couple of small modifications that makes it compatible with old gcc versions. You may download it here svga1925.tbz (808237 bytes) tar archive packed with bzip2.
Note. Modules compile correctly but the boot process does not execute the scripts in e.g. rc3.d so the modules have to be inserted manually after a reboot.