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essary operating-system-staff resources to develop and distribute an official patch. |
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Months passed. The Motorola guys pestered their Xerox field-support rep, to no avail. Finally they decided to take direct action, to demonstrate to Xerox management just how easily the system could be cracked and just how thoroughly the security safeguards could be subverted. |
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They dug around in the operating-system listings and devised a thoroughly devilish set of patches. These patches were then incorporated into a pair of programs called 'Robin Hood' and 'Friar Tuck'. Robin Hood and Friar Tuck were designed to run as 'ghost jobs' (daemons, in Unix terminology); they would use the existing loophole to subvert system security, install the necessary patches, and then keep an eye on one another's statuses in order to keep the system operator (in effect, the superuser) from aborting them. |
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One fine day, the system operator on the main CP-V software development system in El Segundo was surprised by a number of unusual phenomena. These included the following: |
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Tape drives would rewind and dismount their tapes in the middle of a job. |
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Disk drives would seek back and forth so rapidly that they would attempt to walk across the floor (see walking drives). |
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The card-punch output device would occasionally start up of itself and punch a lace card. These would usually jam in the punch. |
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The console would print snide and insulting messages from Robin Hood to Friar Tuck, or vice versa. |
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The Xerox card reader had two output stackers; it could be instructed to stack into A, stack into B, or stack into A (unless a card was unreadable, in which case the bad card was placed into stacker B). One of the patches installed by the ghosts added some code to the card-reader driver after reading a card, it would flip over to the opposite stacker. As a result, card decks would divide themselves in half when they were read, leaving the operator to recollate them manually. |
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Naturally, the operator called in the operating-system developers. They found the bandit ghost jobs running, and gunned |
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