On some m68k-based Texas Instruments graphing calculators, high memory addresses that go beyond the physical memory can be used to access the physical memory (the address space folds itself over the physical memory). This range of addresses is called ghost space, because it mirrors the actual physical space.
For TI-89 programmers, ghost space starts from address 0x40000, and it is widely used to circumvent some of the protections introduced with the HW2 (hardware version 2) release of the calculator. This became a compatibility issue with the release of HW3 (the Ti-89 Titanium), where it is disabled, and patching the ROM (HW3Patch) becomes necessary.
Famous quotes containing the words ghost and/or space:
“‘Dear Captain Smith,’ the ghost replied, ‘you’ve used me ungenteelly.
The crowner’s quest goes hard with me because I’ve acted frailly,
And Parson Biggs won’t bury me, though I am dead Miss Bailey.’”
—George Colman (1762–1836)
“If we remembered everything, we should on most occasions be as ill off as if we remembered nothing. It would take us as long to recall a space of time as it took the original time to elapse, and we should never get ahead with our thinking. All recollected times undergo, accordingly, what M. Ribot calls foreshortening; and this foreshortening is due to the omission of an enormous number of facts which filled them.”
—William James (1842–1910)