Octave requires approximately 50MB of disk storage to unpack and install (significantly less if you don't compile with debugging symbols).
Octave has been compiled and tested with g++ and libg++ on a SPARCstation 2 running SunOS 4.1.2, an IBM RS/6000 running AIX 3.2.5, DEC Alpha systems running OSF/1 1.3 and 3.0, a DECstation 5000/240 running Ultrix 4.2a, and i486 systems running Linux. It should work on most other Unix systems that have a working port of g++ and libg++.
In order to build Octave, you will need a current version of g++, libg++, and GNU make. If you don't have these tools, you can get them from many anonymous ftp archives, including ftp.che.utexas.edu, ftp.uu.net, prep.ai.mit.edu, and wuarchive.wustl.edu, or by writing to the FSF at 675 Mass Ave, Cambridge, MA 02139, USA.
Currently, Octave can only be compiled with the GNU C++ compiler. It would be nice to make it possible to compile Octave with other C++ compilers, but the maintainers do not have sufficient time to devote to this. If you are interested in working to make Octave portable to other compilers, please contact email@example.com.