I got a bit of spare time to go through some of the documentation I received with my recent HP 2100 systems. I have found an incredible item in there! The notebook is about 3 inches thick. It is a training manual along with hundreds of pages of handwritten notes on the Internals of HP Timeshare BASIC. Not only does it describe all the byte by byte formats of OS tapes, SLEEP and HIB tapes, OS and user disc layouts on a sector by sector basis, but it also has diagrams of every data structure in RAM and on disc related to the internal operation of the OS. In addition, it even has over a hundred pages of detailed flowcharts on how every system module operates. These are not general flowcharts, but flowcharts written from a datastructure standpoint. These flowcharts give blow by blow descriptions of exactly what fields in every data structure are modified when that module runs and why. Not just the system modules, but every BASIC statement, user command, operator command, etc all the way down to the scheduler, mux driver, etc. With this information, one could very easily (albeit time consuming) write TSB from scratch. I'll have to scan all this and put it online for interested parties! Jay West