t68@nikhefh.hep.nl (Jos Vermaseren) (02/03/88)
The use of interrupts via Ctrl-C is purely limited to calls to Gemdos. When the normal I/O functions of Gemdos are called and there is a need to put a character on the screen there is first a check whether the BIOS (via Bconstat) has a new character and if so whether this is one of the special characters (Ctrl-S, Ctrl-Q, Ctrl-C and a few more). If so the appropriate action is taken. This makes it necessary for Gemdos to have its own input buffers. During the programming there came a small bug in those and if one has a program that uses input characters, but slower than the user types them in it is possible to crash (hard to do intentionally). If there is a need to circumvent the Ctrl-C there are two possibilities: 1: use Crawio for all screen I/O. This is one of the few Gemdos functions that doesn't test for Ctrl-C etc. 2: Get the characters via Bconin and write them via Bconout. This last method is the faster, but in a shell it is now impossible to redirect the screen I/O. Using Bconout with device number 5 allows the user to also put the non ASCII characters on the screen. Concerning the above bug and the recent remark from DRI: I think it is quite impressive that one person put Gemdos together in one month. It leaves however more questions than were answered: Why is it then so difficult to have somebody spend another month making it into a great file system with speed and even fewer bugs? It would result in something that DRI could be proud of rather than that many people complain about the piece of work that they sold. What are the great programs that this kind of people make during all those other months? Jos Vermaseren T68@nikhefh.hep.nl