Dumb Waiter Read online

  "Just ahead. The big cut-stone house on the right-with part of the roof caved in."

  Mitch twisted a dial in the heart of the pilot-computer, and the car screeched to a stop at the curb. The girl lurched forward.

  "You woke the baby," she complained. "Why stop here? We're still in the city limits."

  "I don't know," he murmured, staring thoughtfully at the dark hulk of the two-story mansion set in a nest of oaks. "Just sort of a hunch."

  There was a long silence while Mitch chewed his lip and frowned at the house.

  "I hear a telephone ringing," she said.

  "Central calling Mayor Sarquist. You can't tell. It might have been ringing for three years."

  She was looking out the rear window. "Mitch-?"

  "Huh?"

  "There's a cop at the intersection."

  He seemed not to hear her. He opened the door. "Let's go inside. I want to look around. Bring the gun."

  They strolled slowly up the walkway toward the damaged and deserted house. The wind was breathing in the oaks, and the porch creaked loudly beneath their feet. The door was still locked. Mitch kicked the glass out of a window, and they slipped into an immense living room. He found the light.

  "The cop'll hear that noise," she muttered, glancing at the broken glass.

  The noisy clatter of the steel-wheeled skater answered her. The cop was coming to investigate. Mitch ignored the sound and began prowling through the house. The phone was still ringing, but he could not answer it without knowing Sarquist's personal identifying code.

  The girl called suddenly from the library. "What's this thing, Mitch?"

  "What thing?" he yelled.

  "Typewriter keyboard, but no type. Just a bunch of wires and a screen."

  His jaw fell agape. He trotted quickly toward the library.

  "A direct channel to the data tanks!" he gasped, staring at the metal wall panel with its encoders and the keyboard. "What's it doing here?"

  He thought about it briefly. "Must be…I remember: just before the exodus, they gave Sarquist emergency powers in the defense setup. He could requisition whatever was needed for civil defense-draft workers for first aid, traffic direction, and so on. He had the power to draft anybody or anything during an air raid."

  Mitch approached the keyboard slowly. He closed the main power switch, and the tubes came alive. He sat down and typed: Central from Sarquist: You will completely clear the ordinance section of your data tanks and await revised ordinances. The entire city code is hereby repealed.

  He waited. Nothing happened. There was no acknowledgment. The typed letters had not even appeared on the screen. "Broken?" asked the girl.

  "Maybe," Mitch grunted. "Maybe not. I think I know."

  The mechanical cop had lowered his retractable sprockets, climbed the porch steps, and was hammering at the door. "Mayor Sarquist, please!" he was calling. "Mayor Sarquist, please!"

  There was a mahogany desk, several easy chairs, a solid wall of books, and a large safe in another wall. The safe-

  "Sarquist should have some rather vital papers in there," he murmured.

  "What do you want with papers?" the girl snapped. "Why don't we get out of the city while we can?"

  He glanced at her coldly. "Like to go the rest of the way alone?"

  She opened her mouth, closed it, and frowned. She was holding the tommy gun, and he saw it twitch slightly in her hand, as if reminding him that she didn't have to go alone.

  He walked to the safe and idly spun the dial. "Locked," he muttered. "It'd take a good charge of T.N.T… or-"

  "Or what?"

  "Central." He chuckled dryly. "Maybe she'll do it for us." "Are you crazy?"

  "Sure. Go unlock the door. Let the policeman in."

  "No!" she barked.

  Mitch snorted impatiently. "All right, then, I'll do it. Pitch me the gun."

  "No!" She pointed it at him and backed away.

  "Give me the gun!"

  "No!"

  She had laid the baby on the sofa, where it was now sleeping peacefully. Mitch sat down beside it.

  "Trust your aim?"

  She caught her breath. Mitch lifted the child gently into his lap.

  "Give me the gun."

  "You wouldn't!"

  "I'll give the kid back to the cops."

  She whitened and handed the weapon to him quickly. Mitch saw that the safety was on, laid the baby aside, and stood up. "Don't look at me like that!" she said nervously.

  He walked slowly toward her.

  "Don't you dare touch me!"

  He picked up a ruler from Sarquist's desk, then dived for her. A moment later she was stretched out across his lap, clawing at his legs and shrieking while he applied the ruler resoundingly. Then he dumped her on the rug, caught up the gun, and went to admit the insistent cop.

  Man and machine stared at each other across the threshold. The cop radioed a visual image of Mitch to Central and got an immediate answer.

  "Request you surrender immediately sir."

  "Am I now charged with breaking and entering?" he asked acidly.

  "Affirmative."

  'You planning to arrest me?"

  Again the cop consulted Central. "If you will leave the city at once, you will be granted safe passage."

  Mitch lifted his brows. Here was a new twist. Central was doing some interpretation, some slight modification of ordinance. He grinned at the cop and shook his head.

  "I locked Mayor Sarquist in the safe," he stated evenly. The robot consulted Central. There was a long twittering of computer code. Then it said, "This is false information."

  "Suit yourself, tin boy. I don't care whether you believe it or not."

  Again there was a twittering of code. Then: "Stand aside, please."

  Mitch stepped out of the doorway. The subunit bounced over the threshold with the aid of the four-footed sprockets and clattered hurriedly toward the library. Mitch followed, grinning to himself. Despite Central's limitless "intelligence," she was as naive as a child.

  He lounged in the doorway to watch the subunit fiddling with the dials of the safe. He motioned the girl down, and she crouched low in a corner. The tumblers clicked. There was a dull snap. The door started to swing.

  "Just a minute!" Mitch barked.

  The subunit paused and turned. The machine gun exploded, and the brief hail of bullets tore off the robot's antenna. Mitch lowered the gun and grinned. The cop just stood there, unable to contact Central, unable to decide. Mitch crossed the room through the drifting plaster dust and rolled the robot aside. The girl whimpered her relief and came up out of the corner.

  The cop was twittering continually as it tried without success to contact the Coordinator. Mitch stared at it for a moment, then barked at the girl, "Go find some tools. Search the garage, attic, basement. I want a screwdriver, pliers, soldering iron, solder, whatever you can find."

  She departed silently.

  Mitch cleaned out the safe and dumped the heaps of papers, money, and securities on the desk. He began sorting them out. Among the various stacks of irrelevant records he found a copy of the original specifications for the Central Coordinator vaults, dating from the time of installation. He found blueprints of the city's network of computer circuits, linking the subunits into one. His hands became excited as he shuffled through the stacks. Here were data. Here was substance for reasonable planning.

  Heretofore he had gone off half-cocked and quite naturally had met with immediate failure. No one ever won a battle by being good, pure, or ethically right, despite Galahad's claims to the contrary. Victories were won by intelligent planning, and Mitch felt ashamed of his previous impulsiveness. To work out a scheme for redirecting Central's efforts would require time. The girl brought a boxful of assorted small tools. She set them on the floor and sat down to glower at him.

  "More cops outside now," she said. "Standing and waiting. The place is surrounded."

  He ignored her. Sarquist's identifying code-it had to be h
ere somewhere.

  "I tell you, we should get out of here!" she whined. "Shut up."

  Mitch occasionally plucked a paper from the stack and laid it aside while the girl watched.

  "What are those?" she asked.

  "Messages he typed into the unit at various times." "What good are they?"

  He showed her one of the slips of yellowed paper. It said: Unit 67-BJ is retired for repairs. A number was scrawled in one corner: 5.00326.

  "So?"

  "That number. It was his identifying code at the time." "You mean it's different every day?"

  "More likely, it's different every minute. The code is probably based on an equation whose independent variable is time and whose dependent variable is the code number."

  "How silly!"

  "Not at all. It's just sort of a combination lock whose combination is continuously changing. All I've got to do is find the equation that describes the change. Then I can get to Central Coordinator."

  She paced restlessly while he continued the search. Half an hour later he put his head in his hands and gazed despondently at the desk top. The key to the code was not there.

  "What's the matter?" she asked.

  "Sarquist. I figured he'd have to write it down somewhere. Evidently he memorized it. Or else his secretary did. I didn't figure a politician even had sense enough to substitute numbers in a simple equation."

  The girl walked to the bookshelf and picked out a volume. She brought it to him silently. The title was Higher Mathematics for Engineers and Physicists.

  "So I was wrong," he grunted. "Now what?"

  He shuffled the slips of paper idly while he thought about it. "I've got eleven code numbers here, and the corresponding times when they were good. I might be able to find it empirically."

  "I don't understand."

  "Find an equation that gives the same eleven answers for the same eleven times, and use it to predict the code number for now."

  "Will it work?"

  He grinned. "There are an infinite number of equations that would give the same eleven answers for the same eleven substitutions. But it might work, if I assume that the code equation was of a simple form."

  She paced restlessly while he worked at making a graph with time as the abscissa and the code numbers for ordinates. But the points were scattered across the page, and there was no connecting them with any simple sort of curve. "It almost has to be some kind of repeating function," he muttered, "something that Central could check by means of an irregular cam. The normal way for setting a code into a machine is to turn a cam by clock motor, and the height of the cam's rider is the code number for that instant."

  He tried it on polar coordinates, hoping to get the shape of such a cam, but the resulting shape was too irregular to be possible, and he had no way of knowing the period of the repeating function.

  "That's the craziest clock I ever saw," the girl murmured. "What?" He looked up quickly.

  "That electric wall clock. Five minutes ahead of the electric clock in the living room. But when we first came it was twenty minutes ahead."

  "It's stopped, maybe."

  "Look at the second hand."

  The red sweep was running. Mitch stared at it for a moment, then rose slowly to his feet and walked to her side. He took the small clock down from its hook and turned it over in his hands. Then he traced the cord to the wall outlet. The plug was held in place by a bracket so that it could not be removed.

  The sweep hand moved slowly, it seemed. Silently he removed the screws from the case and stared inside at the works.

  Then he grunted surprise. "First clock I ever saw with elliptical gears!"

  "What?"

  "Look at these two gears in the train. Ellipses, mounted at the foci. That's the story. For a while the clock will run faster than the other one. Then it'll run slower." He handled it with growing excitement. "That's it, Marta-the key. Central must have another clock just like this one. The amount of lead or lag-in minutes-is probably the code!"

  He moved quickly to the direct-contact unit. "Tell me the time on the other clock!"

  She hurried into the living room and called back, "Ten-seventeen and forty seconds…forty-five…fifty-"

  The other clock was leading by five and one-quarter minutes. He typed 5.250 on the keyboard. Nothing happened. "You sure that's right?" he called.

  "It's now ten-eighteen-ten… fifteen…twenty."

  The clock was still slowing down. He tried 5.230, but again nothing happened. The unit refused to respond. He arose with an angry grunt and began prowling around the library. "There's something else," he muttered. "There must be a modifying factor. That clock's too obvious anyway. But what else could they be measuring together except time?"

  "Is that another clock on his desk?"

  "No, it's a barometer. It doesn't-"

  He paused to grin. "Could be! The barometric pressure difference from the mean could easily be mechanically added or subtracted from the reading of that wacky clock. Visualize this, inside of Central: The two clock motors mounted on the same shaft, with the distance between their indicator needles as the code number. Except that the distance is modified by having a barometer rigged up to shift one of the clocks one way or the other on its axis when the pressure varies. It's simple enough."

  She shook her head. Mitch took the barometer with him to the unit. The dial was calibrated in atmospheres, and the pressure was now 1.03. Surely, he thought, for simplicity's sake, there would be no other factor involved in the code. This way, Sarquist could have glanced at his watch and the wall clock and the barometer and could have known the code number with only a little mental arithmetic. The wall time minus the wrist time plus the barometer's reading.

  He called to the girl again, and the lag was now a little over four minutes. He typed again. There was a sharp click as the relays worked. The screen came alive, fluttered with momentary phosphorescence, then revealed the numbers in glowing type.

  "We've got it!" he yelled to Marta.

  She came to sit down on the rug. "I still don't see what we've got."

  "Watch!" He began typing hurriedly, and the message flashed neatly upon the screen.

  CENTRAL FROM SARQUIST. CLEAR YOUR TANKS OF ALL ORDINANCE DATA, EXCEPT ORDINANCES PERTAINING TO RECORDING OF INFORMATION IN YOUR TANKS. PREPARE TO RECORD NEW DATA.

  He pressed the answer button and the screen went blank, but the reply was slow to come.

  "It won't work!" Marta snorted. "It knows you aren't Sarquist. The subunits in the street have seen us."

  "What do you mean by 'know,' and what do you mean by 'see'? Central isn't human."

  "It knows and it sees."

  He nodded. "Provided you mean those words in a mechanical sense. Provided you don't imply that she cares what she knows and sees, except where she's required to 'care' by enforced behavior patterns-ordinances."

  Then the reply began crawling across the screen. SARQUIST FROM CENTRAL. INCONSISTENT INSTRUCTIONS. ORDINANCE 36-J, PERTAINING TO THE RECORDING OF INFORMATION, STATES THAT ORDINANCE DATA MAY NOT BE TOTALLY VOIDED BY YOU EXCEPT DURING RED ALERT AIR WARNING.

  "See?" the girl hissed.

  DEFINE THE LIMITS OF MY AUTHORITY IN PRESENT CONDITIONS, he typed. MAY I TEMPORARILY SUSPEND SPECIFIC ORDINANCES?

  YOU MAY SUSPEND SPECIFIC ORDINANCES FOR CAUSE, BUT THE CAUSE MUST BE RECORDED WITH THE ORDER OF SUSPENSION.

  Mitch put on a gloating grin. READ ME THE SERIES NUMBERS OF ALL LAWS IN CRIMINAL AND TRAFFIC CODES.

  The reaction was immediate. Numbers began flashing on the screen in rapid sequence. "Write these down!" he called to the girl.

  A few moments later, the flashing numbers paused. WAIT, EMERGENCY INTERRUPTION, said the screen.

  Mitch frowned. The girl glanced up from her notes. "What's-"

  Then it came. A dull booming roar that rattled the windows and shook the house.

  "Not another raid!" she whimpered.

  "It doesn't sound like-"

  Letters be
gan splashing across the screen. EMERGENCY ADVICE TO SARQUIST. MY CIVILIAN DEFENSE CO-ORDINATOR HAS BEEN DESTROYED. MY ANTIAIRCRAFT COORDINATOR HAS BEEN DESTROYED. ADVISE, PLEASE.

  "What happened?"

  "Frank Ferris!" he barked suddenly. "The Sugarton crowd-with their dynamite! They got into the city."

  CENTRAL FROM SARQUIST, he typed. WHERE ARE THE DAMAGED COORDINATORS LOCATED?

  UNDERGROUND VAULT AT MAP COORDINATES K-81.

  "Outside the city," he breathed. "They haven't got to the main tanks yet. We've got a little time."

  PROCEED WITH ORDINANCE LISTING, he commanded.

  Half an hour later they were finished. Then he began the long task of relisting each ordinance number and typing after it: REPEALED; CITY EVACUATED.

  "I hear gunshots," Marta interrupted. She went to the window to peer up and down the dimly lighted streets.

  Mitch worked grimly. It would take them a couple of hours to get into the heart of the city, unless they knew how to capture a robot vehicle and make it serve them. But with enough men and enough guns, they would wreck subunits until Central withdrew. Then they could walk freely into the heart of the city and wreck the main coordinators, with a consequent cessation of all city services. Then they would be free to pillage, to make a mechanical graveyard of the city that awaited the return of man.

  "They're coming down this street, I think," she called.

  "Then turn out all the lights!" he snapped, "and keep quiet." "They'll see all the cops out in the street. They'll wonder why."

  He worked frantically to get all the codes out of the machine before the Sugarton crowd came past. He was destroying its duties, its habit patterns, its normal functions. When he was finished it would stand by helplessly and let Ferris's gang wreak their havoc, unless he could replace the voided ordinances with new, more practical ones.

  "Aren't you finished yet?" she called. "They're a couple of blocks away. The cops have quit fighting, but the men are still shooting them."

  "I'm finished now!" He began rattling the keyboard frantically.

  SUPPLEMENTAL ORDINANCES: #1: THERE IS NO LIMIT OF SUBUNIT EXPENDITURE.

  YOU WILL NOT PHYSICALLY INJURE ANY HUMAN BEING, EXCEPT IN DEFENSE OF CENTRAL COORDINATOR UNITS.