peter%sugar@uunet.UU.NET (Peter da Silva) (11/03/88)
One thing that occurs to me is that threads basically refine the question of what is the basic unit of resource allocation by allowing multiple execution streams to share a block of other resources. Some of these have been available from the beginning. Open files, for example, though the prevalence of the standard I/O library has limited the usefulness of this feature... you may recall that in the version 6 shell this was how control structures were implemented. As an aside, it has occurred to me that this was really a nice idea... and rather than abandoning it adding a new standard file descriptor to the trinity of stdin, stdout, and stderr might have been better. Stdcmd would be retained as the command standard input even if stdin was redirected. Other operating systems have mechanisms like this that work reasonably well... Back to the point... are there not cases where you want to share your address space (and avoid the overhead of MMU register saves and restores when switching execution context) but you don't want to share cheaper resources (open files, and such)? Has there been any work done on this? -- Peter da Silva `-_-' peter@sugar.uu.net Have you hugged U your wolf today? Disclaimer: I accept full responsibility for my own typos.