> From: Stephen Leake [mailto:[log in to unmask]] > Sent: Thursday, February 07, 2002 6:33 AM > > Ah, the luxury of having the bandwidth to upload the entire code set > :). > > I never had the experience directly, but apparently in the Bad Old > Days you could not do that, and had to upload the smallest possible > patches. Actually, some of my current missions still plan to operate > in that mode. We still operate that way due to limited contact time with our birds. "Patchability" can become a driving factor in the software design and tool selection. Rational Software has a "patch linker" which supports small code patches. Similar tricks can be performed with GNU tools. Changes to data structures present the biggest problem when patching flight software. Ada provides a lot of options (access functions, reserving space with 'Size rep clause, etc.), but the safest approach seems to be uploading a new flight image (which may require multiple orbits).