A new programming language and operating system for HP processors is currently being developed for release as freeware. I expect it will be released this summer. Many HP systems ran as embedded control systems rather than as general data crunching machines. As a result, there is not the same level of software support as there is for machines like the PDP-8 or PDP-11. For operating systems, your pretty much limited to the various flavors of RTE or multi-user basic. Much older systems ran an OS called DOS, but this will fall well short of any modern concept of what a DOS should be. Most of the software consisted of software development tools to build instrumentation and control systems, as HP computers were initially developed to automate the first HP digital volt meters, etc. Sergio Pedraja Cabo wrote: