I've heard it mentioned repeatedly that in the climax of A Deepness in the Sky, Sherkaner Underhill's and Pham Nuwen's gambits somehow come close to mutually cancelling and giving Nau victory.

As I understand it, Pham's gambit involved using his localizers to cut off Nau's access to the zipheads. Underhill's gambit involved... using the zipheads to screw with Nau in some way? I get in principle how the two would tend to tread on one another, but can anyone give me a play-by-play of how the interaction between the gambits went wrong?

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Both sides knew that the the biggest advantage of the Emergent was the Focused. They depended so much on it that it was clear to both sets of conspirators that if you could control them or take them out of the equation, things would be much easier.

Pham and Ezr

Pham's plan, at least after his revelation by Reynolt, was indeed to cut off all access to the Focused. This was something of a desperation move... if Reynolt hadn't found him at that moment, he could have disabled the power cutoff and ensure the localizers got powered no matter what. With that, he might have been able to do it more subtly, using his localizers to transmit false data to key focused personnel, which they depended on and trusted, and thus could do anything from accessing weapon stores without security alerting him (and then assassinating key members of the team) to, perhaps, turning off all the lights and using his localizer-knowledge to be the one person who could see.

The closest we get to a detailed description of their plan that I could find was this:

Pham and Ezr's plan was proceeding down its own schedule. Except for a few old systems, a few electromechanical backups, the Qeng Ho localizers could have total control. Pham and Ezr were finally moving toward real sabotage—most important the Hammerfest wireless-power cutoff. That switch was an almost pure mechanical link, immune to all subtlety.

But Pham had one more use for localizers. True grit. These last few Msecs, they had built up layers of grit near that switch, and set up similar sabotage in other old systems, and aboard the Invisible Hand. The last hundred seconds would involve flagrant risk. It was a trick that they could try only once, when Nau and his gang were most distracted with their own takeover. If the sabotage worked—when it worked—the Qeng Ho localizers would rule.

And our time will come.

Which implies but doesn't actually say that some subtle manipulation was planned, however, the localizers are extremely powerful even if you don't directly control the systems of the other side, as long as you can disable them, so we don't completely know.

Regardless, once his cover was blown and he was on the run, his plan was solely to disable Nau's advantage of the Focused and then win any way he could:

Pham shook his head. "I'm here to win, Trud." He raised his little dart gun up where Silipan could see. "And you're going to help. We're going out to the group room, and you're going to cut off all ziphead support—"

Silipan brushed irritably at Nuwen's gun hand. "Impossible. There's a critical need for them, supporting the ground op."

"Supporting Nau's Spider-extermination program? All the better to cut them off right now. It should have an interesting effect on the Podmaster's lake, too."

At this point he believed Nau was in the vicinity of the lake and might well have hoped that it would rise up and kill him, saving him one of his most major adversaries. In fact, generally speaking, Pham's true adversaries were few... there were only two Podmasters, Reynolt (who was loyal to the podmasters, not any specific philosophy) and Kal Omo and his limited security team. Take out all of them, and most of the rest of the Emergents would likely follow any strong personality who took charge of the situation.

At the time of his confrontation with Underhill, he was trying to use the zipheads he had access to for support:

"Now I want you to do a damage assessment. Is there any way you can get work from your people here, with Nau cut off?"

Trud shrugged angrily. "You know that's imposs—" He looked up again at Pham. "Maybe, maybe there are some trivial things. We do offline computing. I might be able to trick the numerical control zipheads... ."

And eventually, an idea to try and get them to control the electric jets, but that was spur of the moment planning.

The Spiders' Counterlurk

Underhill on the other hand, had already won the translators over to their side. Now, so much of what Nau was doing depended on translators, or specialties that worked closely with translators.

Jau's last day before departure was busy, filled with final checks and provisioning. There would be more than a hundred zipheads and staff. Jau didn't learn just which specialties were represented, but it was obvious that the Podmasters wanted to manipulate the Spiders' networks intensively, without the ten-second time delay of L1 operations. That was reasonable. Saving the Spiders from themselves would involve some incredible frauds, perhaps the taking over of entire strategic weapons systems.

Manipulating Spider networks takes a LOT of knowledge of what they're saying, so you can substitute something plausible, and on a military level as well, knowing exactly which targets are priorities. Imagine, even if you had the superhuman focus to make all the corrections to the enemy's datastream that were necessary to fit with your cover story, you could target your weapons exactly where you wanted... but you didn't have the language knowledge to know what needed substituting and what the key targets should be? So the translators were the most important bit, and what's more, they were heavily interfaced with the 'rote-layer' zipheads, to the point that they could give them commands.

We see a hint of this earlier on:

Rita pulled her head out of the doorway to look up and down the corridor. "Yeah. But you know, after you got her back to work? All the others just quietly returned to their rooms. These translator types have more control functionality than military zips. All you have to do is convince the alpha member, and everyone falls into line." She grinned. "But I guess we've seen this before, the way the translators can control the rote-layer zips. They're the keystone components, all right."

So, being able to influence the translators to work for them, the Spiders also had an in to the rote-layer zipheads, the ones who are designed to be reassigned to any task as necessary, and a key component.

We see this when Trud explains how programming works:

"Ah, see? We have them partitioned into three groups. The top third is rote-layer processing, zipheads that can be easily retargeted. They're great for routine tasks, like direct queries.

These zipheads were key to almost every part of the automaton in general, even things that had nothing to do with translation but rather internal security - you might need, say, a body language specialist to interpret what a person is feeling, but to watch the feeds and route that information to the specialist, you need the rote-layer zips. And for other things like understanding the proper context to ambiguous commands. If these rote-layer zips were instructed to give translators commands a high priority, they might well be able to give them any instruction, even ones outside of translations. Focused peoples are not known for independent creative thought or rebellion, so there'd be no reason (particularly in a limited-resources situation like the expedition, rather than on the Emergents homeworld), to monitor them constantly and make sure their instructions are appropriate. It would probably be more important to monitor their HANDLERS, but the handlers have little idea of what is going on, they can't read the Spider text to see what is and isn't important.

It's also probable that the translators had direct or indirect access to various other teams and could potentially interfere intentionally, as we've seen happen (possibly accidentally) on a couple of occasions:

Twenty Ksec into the workday, the ziphead support for two of the research teams fell into deadlock, a temperamental snit that Reynolt could have cleared in a few seconds. Phuong and Silipan whacked at the problem for 6Ksecs, then announced that the zipheads involved would be down for the rest of the day. No, they weren't translators—but Trixia had been working with one of them, some kind of geologist.

And this event which might well have caused the awakening of the translators:

Some parts of the mystery were solved right away. Trud's query right at the beginning of the debate had triggered a search across many specialities. That was the reason so many zipheads had been listening to the debate. Their analysis had proceeded very normally for several hundred seconds, but then as the results were posted, there was a surge in communication between the translators. Normally, that was consultative, tuning the words that they spoke aloud. This time, it was deadly nonsense. First Trixia and then most of the other translators began to drift, their brain chemistry indicating an uncontrolled excursion of the rot. Real damage had been done even before Trixia attacked Xopi Reung, but that had marked the beginning of the massive runaway. Whatever was being communicated within the ziphead net provoked a cascade of similar flareups.

So, the translators get awakened and start taking sides - the Spiders' side. They make contact first with Underhill and his family and essentially their loyalty changes to them. Underhill gets virtually all the information they're able to provide him (which is a lot) and realizes he can get them to give false information to the aliens. He also sets up videomancy as a cover - providing a data stream that only the translators can interpret:

But it got harder and harder to disguise the counterlurk. Videomancy was a great cover, it let us have independent hardware and a covert data stream right under the humans' snouts.

Lots of planning, followed, and allowing the Emergent's plan to go on. Then, when they needed to, they planned to use the translators' access to the rote-layer zipheads to:

  1. Alter targeting parameters/launch codes/etc where needed to prevent an apocalypse from their own weapons.
  2. Stop the corruption of their networks and reveal the Invisible Hand, which, despite its weaponry, was extremely vulnerable and depended on secrecy:

There weren't many missile sites in the Spiders' far north. But what there were would be nuke armed. Even a single hit could cripple the Hand. Jau reached to enable his pilots—

  1. Take control of the hand by using the rote-layer zips to affect the piloting zips and land the Hand where Spiders could take it.

The Deadlock

Unfortunately, Pham took the zipheads at L1 offline, at a critically bad moment for the Spiders... which meant that the ones on the Invisible Hand were still able to enact their plan to launch Spider missiles (from the Kindred) at other Spider targets and start the war... although, for many reasons, not as bad a one as was planned, and until Pham restored access to the translators, the Lighthill team couldn't do the other parts of their plan.

One of the zipheads—Bonsol—interrupted, the typical irrelevance of the Focused: "There are millions of people on the ground. They will start dying in a few seconds."

The comment actually seemed to derail Pham. Even the new Pham Trinli was still an amateur when it came to dealing with zipheads. "Yeah," he said, more to himself than to Silipan or the ziphead. "But at least the Spiders have a chance. Without our zipheads, Ritser can't tighten the screws any more." Of course, Bonsol ignored the reply, just went on tapping at her keys.

Bonsol is of course speaking for Underhill here, with a timelag and translation lag making the conversation a bit weird.

Bonsol interrupted. "Ritser can't tighten the screws, but we can't loosen them either." She was laughing, almost inaudibly. "What an intriguing thing. We have a deadlock."

Trud motioned for Pham to move back toward the ceiling, out of range of this random ziphead commentary. "They'll go on like that forever."

But Pham turned back to the ziphead, abruptly giving her all his attention. "What do you mean ‘we have a deadlock'?" he said quietly.


The silence stretched for ten or fifteen seconds. Then, abruptly, Bonsol's head snapped up and she stared directly into Pham's eyes—the way a ziphead almost never did, except when role-playing. "I mean you're blocking us and we're blocking you," she said. "My victory thought you were all monsters, that we couldn't trust any of you. And now we are all paying for that mistake."


If the deadlock were to end, can you run everything? And afterwards...we would be at your mercy afterwards. How can we trust you?"

Bonsol's gaze had wandered. She didn't answer, and her hands roamed her console. Silent seconds ticked by, but now a cold surmise stole up Trud's spine.No. Sharp on ten seconds, Trixia Bonsol spoke again: "If you restore full access, we can control the most important things. At least that was the plan. As for trust..." Bonsol's face twisted in a strange smile, mocking and wistful all at once. "Well, you know us much better than the reverse. You must choose your own monsters."

When Trixia/Underhill said "you're blocking us and we're blocking you," specifically Underhill was blocking Pham's efforts to get the zipheads to work for him and provide him the information he needed (or, by virtue of their already working for Underhill, they were resisting Pham's efforts to take them off task), and Pham was blocking them by not allowing them to communicate widely.

Nau might not have won if they hadn't stopped blocking each other, but Pham could well have died if Nau was able to get access, and many more Spiders would have died before Nau restored ziphead control and the Lighthill team could resume taking over the entire system... and, if the entire Lighthill team somehow died, as the only ones who knew about the Counterlurk, then yes, they might have lost completely.

One more thing bears noting about the deadlock: It's quite possible that the Spiders taking more active control made Reynolt's suspicions of Trinli more urgent, she thought he was getting more bold, when really it was a combination of that and the Spiders.

  • Ahhh, thank you! I was missing the 'awakening' of the translators, and their subversion by the Spiders. That makes it all make sense. Aug 9, 2019 at 17:05
  • Do you also happen to know how Underhill got two-way communication with Trixia? I've recently re-read the book and still haven't seen where this happens.
    – rptb1
    Jun 6, 2021 at 17:18
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    @rptb1 I don't have it on hang right now but I do recall it specifically said that Trixia reached out to Underhill, after the incident involving his children's kidnapping (and he thought it was an AI at that point). At that point, the Emergents already had hooks into the developing computer networks, and so arranging a two-way communication would not be that hard assuming she had enough zipheads on her side (which it seems she did), and a more secure means through the videomancy and game helms which hid streams of data most humans couldn't visually process. Jun 8, 2021 at 23:08
  • @starpilotsix Yes I assume that's how it works (it must be how, really) but I feel like there's no hint of it before or when it happens, and that it's suddenly mentioned at the denoument without an explanation. A minor flaw in a great book. Thanks for the reply!
    – rptb1
    Jun 10, 2021 at 6:12
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    @rptb1 It was established that they were already purposefully communicating with spiders by pretending to be an anonymous inventor in order to distribute technology to the spiders. This was with Nau's approval. So overt communication was already happening and the framework was in place to directly talk to the spiders via their own networks and in their language. Sep 11, 2022 at 22:31

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