Path: utzoo!attcan!uunet!husc6!uwvax!oddjob!ncar!ames!ucsd!ucsdhub!hp-sdd!hplabs!hpda!hp-sde!hpfcdc!hpfclp!diamant From: diamant@hpfclp.SDE.HP.COM (John Diamant) Newsgroups: comp.windows.x Subject: Re: changing menu widget behavior Message-ID: <9740035@hpfclp.SDE.HP.COM> Date: 1 Jul 88 19:26:33 GMT References: <11393@steinmetz.ge.com> Organization: HP SDE, Fort Collins, CO Lines: 30 > Unfortunately, there's a flaw with backing store: you can't insist on > it. > > You can't insist on it because there are servers out there (e.g., the > X terminal that was being shown at Usenix) with a fixed amount of > memory, and they simply can't commit to all backing store requests. Yes, that's true. Unfortunately, that makes it considerably less useful than it would be otherwise. If you have an application that needs backing store or something like it to run effectively (a paint program that allows arbitrary pixels to be turned on and off is an example) then you are forced to maintain your own backing store via pixmaps and/or images, since you can never be assured that the server will honor your backing store. That means even if it has the memory and will honor all uses of it, you still have to manange your own duplicate copy. That's a waste of time and resources (though you still get the benefit of the server's ability to be more efficient in handling it when it can). What might help would be a way to ask the server to reserve backing storage space for a particular window such that it could decide at the beginning whether it had the maximum space required and reserve it right then. If it refuses (whether it had the space or not), then the application could fall back to the local maintenance approach. This would avoid the redundancy for most servers (workstations with large virtual memory). John Diamant Software Development Environments Hewlett-Packard Co. ARPA Internet: diamant@hpfclp.sde.hp.com Fort Collins, CO UUCP: {hplabs,hpfcla}!hpfclp!diamant