A lengthy period ago, whenever I was a university undergrad, I spent several period operating on device video games. This was in the 8-bit PC era, whenever the gaming hardware was nearly impossibly dilatory by today’s standards.

It power not astonishment you, then, to study that equivalent programmers of yore did all sorts of insane things to create their games run at playable speeds. Crazy, insane things.

This is a narrative concerning one of those things.

While I’ve done my finest to recall the crucial details, I may have gotten several things wrong. If I have, delight forgive me. It was a lengthy period ago.

(Note: This article contains several small images as inline-data URLs that several nourish readers apparently don’t grip well. If you can’t see the images in your feed, click through to the first part to see them.)

Update 2013-12-16: There have been many of awesome comments concerning this narrative on Hacker News and Proggit, as fine as here on the blog. Thanks for sharing, everyone!

The set-up

A companion of mine, a gifted programmer, was nearly completed alongside a new game. Somehow, he had squeezed into a 1980’s-era PC, beautiful faithfully, what was at the period a graphically notable coin-op equivalent famous at the arcades.

The lone issue was that his type of the equivalent was unplayable. It was too slow, and the choppy motion bankrupt the player’s immersion. It was following all a side-scroller.

My friend, who had been operating on the equivalent during additionally taking a complete burden of university courses, was starting to appear a small frazzled. Fearing that he had missed several uncomplicated optimization, he asked me to obtain a appearance at the code.

I did. But there was no uncomplicated optimization to be had.

The code was tight. Everywhere I looked, he had already done all the things I could think of. Loops had been unrolled. Unneeded draws had been eliminated. All evidence of discarded had vanished.

And, alongside them, our hopes of an uncomplicated fix.

But what concerning a difficult fix? A insane fix?

Well, that was continually a possibility.

Before I get to the insane stuff, however, I should rear up and explain how graphics hardware worked rear then.

How graphics hardware worked rear then

Here’s the quick version: The graphics hardware didn’t do jack squat.

On the PC in question, if you wanted to diagram item onto the screen, you had to do that yourself, byte by byte. No texture mappers, no blitters. Just bytes. Bytes that you had to move yourself.

Fun.

My friend’s equivalent spent most of its period redrawing the background. (Again: side-scroller.) For all frame, it had to diagram nearly a screen’s value of backdrop tiles, shifted for the player’s position.

If my recollection serves me, all tile was 28 by 28 pixels. Each pixel was one of 16 colors, taking fractional a byte to represent. Therefore, tiles were represented in recollection as 28 adjacent rows of 14 bytes each. The archetypal 14 bytes represented the archetypal row, the second 14 bytes the second row, and so on.

The screen, however, was 320 pixels broad by 240 pixels high. In memory, then, a display buffer was laid out as 240 adjacent rows of 160 bytes each.

So whenever copying a tile at location X onto a display buffer location starting at location Y, you had to copy 28 rows. To copy all row, you had to copy 14 bytes. Fortunately, the processor for this equivalent was a 6809, which had a few 16-bit indicator registers and delightful “auto-increment” addressing modes (sort of akin applying the postfix ++ controller to pointers in C). That meant you could copy 4 pixels at a period during advancing the two the X and Y registers in passing:

 LDU ,X++ ; peruse a 2-byte term (= 4 pixels) from origin tile STU ,Y++ ; compose it to display buffer

To copy a complete row, you had to do that seven times, so you power sandwich those lines inside a 7-count loop:

 LDB #7 ; remaining words <- tile width in words @LOOP LDU ,X++ ; peruse a 2-byte term (= 4 pixels) from origin tile STU ,Y++ ; compose it to display buffer DECB ; decrease remaining-word count BNE @LOOP ; iteration during words remain

When you were done copying the row, you needed to advancement the destination pointer Y so that it pointed to the starting location for the next row you would diagram into the display buffer. Since the display buffer was 160 bytes broad and a tile was lone 14 bytes wide, that meant you had to add their difference to Y:

 LEAY 160-14,Y

And, fair akin that, you have copied a row onto the screen.

That’s one. To copy a complete tile, you need to do the identical item 28 times. So, in turn, you sandwich that code inside a 28-count loop.

Putting it all together, and giving names to the crucial numbers, you power end up alongside a subroutine akin this:

;;; crucial constants SCRW = 160 ; screen-buffer width in bytes (= 320 4-bit pixels) TILW = 14 ; background-tile width in bytes (= 28 4-bit pixels) TILH = 28 ; background-tile height in rows WOFF = SCRW - TILW ; s-b offset from end of one tile row to commencement of next COPYTILE ;;; ;;; Copy a 28x28 backdrop tile into a display buffer. ;;; Arguments: ;;; X = starting location of backdrop tile ;;; Y = starting location of destination in display buffer ;;; LDA #TILH ; remaining rows <- tile height @COPYROW LDB #TILW/2 ; remaining words <- tile width in words @LOOP LDU ,X++ ; peruse a term (= 4 pixels) from origin tile STU ,Y++ ; compose it to display buffer DECB ; decrease remaining-word count BNE @LOOP ; iteration during words remain ;; LEAY WOFF,Y ; advancement dst ptr to commencement of next dst row DECA ; decrease remaining-row count BNE @COPYROW ; iteration during rows remain ;; RTS ; done! come back to caller

And that code would be fine.

If you didn’t attention concerning speed.

Caring concerning speed

Knowing that the equivalent is likely going to expend most of its period operating that code, you do what any fine programmer would: commencement counting cycles. Here’s the inner iteration again, alongside setup and finishing, annotated alongside sequence counts:

 LDB #TILW/2 ; 2 cycles (set-up) @LOOP LDU ,X++ ; 8 STU ,Y++ ; 8 DECB ; 2 BNE @LOOP ; 3 ;; LEAY WOFF,Y ; 8 (finishing)

Looking at those counts inside the loop, you’re not apt to young female that you’re burning 21 cycles to copy fair 4 pixels. To copy a complete row, then, plant out to 2 cycles + (7 iterations) * (21 cycles/iteration) + 8 cycles = 157 cycles. Ouch.

But this isn’t your archetypal period at the keyboard. You cognize what to do. Unroll that loop!

 LDU ,X++ ; 8 cycles STU ,Y++ ; 8 LDU ,X++ ; 8 STU ,Y++ ; 8 LDU ,X++ ; 8 STU ,Y++ ; 8 LDU ,X++ ; 8 STU ,Y++ ; 8 LDU ,X++ ; 8 STU ,Y++ ; 8 LDU ,X++ ; 8 STU ,Y++ ; 8 LDU ,X++ ; 8 STU ,Y++ ; 8 LEAY WOFF,Y ; 8 (finishing)

Now, alongside the iteration overhead reduced to zero – you’ve equal eliminated the set-up – all row takes lone 7 * (8 + 8) + 8 = 120 cycles. That’s a 30-percent speed-up. Pretty good.

And that’s anywhere most programmers likely would have remaining it.

But not my friend.

He knew that those ++ operations were costly, 3 cycles apiece. And, alongside the iteration unrolled, he additionally knew exactly anywhere all term to be peruse or written was located alongside regard to X or Y. So he cleverly replaced those 3-cycle post-increments alongside exact offsets. They disbursal lone 1 sequence apiece, and the 0 offset is really free:

 LDU ,X ; 5 cycles STU ,Y ; 5 LDU 2,X ; 6 STU 2,Y ; 6 LDU 4,X ; 6 STU 4,Y ; 6 LDU 6,X ; 6 STU 6,Y ; 6 LDU 8,X ; 6 STU 8,Y ; 6 LDU 10,X ; 6 STU 10,Y ; 6 LDU 12,X ; 6 STU 12,Y ; 6 LEAX TILW,X ; 8 (finishing) LEAY SCRW,Y ; 8 (finishing)

With his optimizations, the sequence figure per row had been reduced to (5 + 5) + 6 * (6 + 6) + (8 + 8) = 98 cycles. Compared to the first code, that’s 60 percent faster:

original_speed = (1*row) / (157*cycle) optimized_speed = (1*row) / (98*cycle) speed_up = optimized_speed / original_speed - 1 = 157 / 98 - 1 = 0.60.

Putting it all together – and, again, I’m going by recollection so the code power have been slightly distinct – the copy-tile subroutine looked item akin this, and it copied a complete tile, all 28 rows, in a lean 2893 cycles:

COPYTILE2 ;;; ;;; Copy a 28x28 display tile into a display buffer. ;;; Arguments: ;;; X = starting location of backdrop tile ;;; Y = starting location of destination in display buffer ;;; Execution time: ;;; 4 + 28 * (82 + 8 + 8 + 2 + 3) + 5 = 2893 cycles ;;; LDA #TILH ; initialize row figure (4 cycles) ;; @COPY1 ;; unroll inner iteration (copies one row of 28 pixels in 82 cycles) LDU ,X ; (1) peruse 4 pixels (5 cycles) STU ,Y ; compose 4 pixels (5 cycles) LDU 2,X ; (2) (6 cycles) STU 2,Y ; (6 cycles) LDU 4,X ; (3) ... STU 4,Y ; ... LDU 6,X ; (4) STU 6,Y ; LDU 8,X ; (5) STU 8,Y ; LDU 10,X ; (6) STU 10,Y ; LDU 12,X ; (7) STU 12,Y ; ;; LEAX TILW,X ; advancement src to commencement of next row (8 cycles) LEAY SCRW,Y ; advancement dst to commencement of next row (8 cycles) DECA ; decrease remaining figure by one (2 cycles) BNE @COPY1 ; iteration during rows remain (3 cycles) ;; RTS ; done! come back to visitant (5 cycles)

This code, all in all, was 60% faster than the naive COPYTILE code we started out with.

But that wasn’t accelerated enough. Not nearly.

So whenever my companion showed me his code and asked if I could create it faster, I really wanted to assistance him. I really wanted to be capable to answer yes.

But I had to answer no. I hated giving that answer. But, studying the code, I couldn’t see any way to speed it up.

And yet, the hook was set.

Later, I couldn’t get the issue out of my head. Maybe I had missed something. I had grown up on Apple II computers and their 6502 processors. My friend’s code, however, was for the 6809. Maybe it afforded optimizations that I didn’t cognize about.

With renewing optimism, I dialed into the university’s archive to admission the cardstock catalog. (These were the days before the World Wide Web.) Through a VT220 terminal emulator, I searched for books concerning the 6809.

There was one. A 6809 microprocessor manual. It was in the engineering library. Luckily, I was an engineering pupil and had sign-out privileges.

Just akin that, I was off to the library.

A insane idea

When I got to the engineering library, I established the publish correct anywhere it was expected to be, looking a small attack up:

The MC6809-MC6809E Microprocessor Programming Manual.

Not bothering to discover a chair, I flipped through the pages standing, looking for several oddball, 6809-specific education that power throw a lot of bytes and throw them fast. Page following page, though, turned up nothing.

Then I came upon PSHS. “Push registers on the hardware stack.”

On my cherished 6502, if you wanted to preserve registers on the stack, you had to do it one enroll at a period and, equal then, by transferring them through the accumulator. It was dilatory and expensive. So I had learned to evade the stack whenever speed mattered.

But on the 6809 you could preserve all of the registers – or any subset of them – alongside a sole instruction. And, amazingly, it disbursal a uncomplicated 5 cycles, affirmative 1 sequence additional per byte pushed.

Since the processor had three 16-bit general-purpose registers – D, X, and Y – I could burden them up and afterward use a sole PSHS education to compose 6 bytes in fair 11 cycles. The corresponding drag instruction, PULS, had the identical low cost.

Further, the 6809 had two stack registers, S and U. I could use one as a origin pointer and the another as a destination pointer. In theory, alongside a sole PULS/PSHU pair, I could copy 6 bytes in 22 cycles.

That’s crazy, insane fast.

Excitement mounting, I headed for the forefront array and reached for my pupil ID. I was going to sign out that fantastic small publish for additional study.

A insane plan

Walking rear to the dorms, I cast my plan.

I would preserve the S and U registers somewhere, and afterward item S at the backdrop tile and U at the display buffer. Then I would drag from S and shove to U, copying 6 bytes at a time, using D, X, and Y as go-betweens. To copy the 14 bytes that create up a row would necessitate three specified iterations, which unrolled would be concerning 60 cycles.

When I reached my room, I established a part of document and sketched it out:

 PULS D,X,Y ; archetypal 6 bytes 11 cycles PSHU D,X,Y ; 11 PULS D,X,Y ; second 6 bytes 11 PSHU D,X,Y ; 11 PULS D ; final 2 bytes 7 PSHU D ; 7 LEAU -WOFF,U ; advancement dst ptr 8

Just 66 cycles, including the after-row adaptation to U that prepares it for the next row. (Note that the adaptation is now negative.) For comparison, the naive row-copy iteration that we looked at before took 157 cycles to do the identical thing. And my friend’s optimized code took 98. Already, this insane idea was looking akin a big win.

Still, that final PULS/PSHU pair! What a clunker. It was needed to grip the final two bytes per row, since the rows were 28 pixels = 14 bytes wide, and 6 doesn’t distinct 14 evenly.

That darn remainder of 2 bytes!

If lone the equivalent had used 24-by-24 tiles instead… But it hadn’t, so I pored through the manual, looking for a way to lesser the disbursal of that inevitable final pair.

And then, by surprise, I struck gold! It was another 6809 oddity, the DP register.

On the 6502 and most 8-bit processors of the era, the lowest 256 bytes of recollection was called the zero page. The zero leaf was particular since its recollection locations had single-byte addresses and could be accessed alongside shorter and normally faster instructions.

The 6809’s designers took this idea one stage further. They let you use the DP enroll to designate any leaf as the zero page, which they called the “direct page.”

But none of my byte-slinging instructions needed to use the straightforward page. That meant I could use the DP enroll as an additional one-byte go-between. Now I could copy 7 bytes per pull-push pair!

And 14 is evenly divisible by 7.

With this change, I could copy a entire 28-pixel row and advancement to the next in fair 5 instructions:

 PULS D,X,Y,DP ; archetypal 7 bytes 12 cycles PSHU D,X,Y,DP ; 12 PULS D,X,Y,DP ; second 7 bytes 12 PSHU D,X,Y,DP ; 12 LEAU -WOFF,U ; advancement dst ptr 8

56 cycles! Fifty. Six. Cycles.

That bit of code made me awareness fair awesome. I had managed to harness all sole accessible enroll on the device for byte-slinging! D, X, Y, U, S, and equal the oddball DP – they were all completely engaged.

I was emotion awesome concerning this solution.

Except for fair one thing…

I’ll have a small additional crazy, please

If you’re acquainted alongside stacks, you may have noticed a subtle flaw in my brilliant plan:

Pushes and pulls activity in contrary directions.

See, I lied concerning that small obstacle of code I fair showed you. It didn’t actually copy one row from a backdrop tile onto the screen. What it really did was interrupt the row into two 7-byte blocks – I’ll call them “septets” – and afterward diagram them onto the display swapped.

Recall that tile rows were laid out sensibly in recollection as 14 adjacent bytes, akin this:

+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | 0 1 2 3 4 5 6 7 8 9 A B C D | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+

So whenever you pulled-and-pushed a row onto the display in 7-byte septets, it would get horizontally divided akin this:

+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | 7 8 9 A B C D | 0 1 2 3 4 5 6 | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+

The archetypal septet was now second, and the second now first. Note, however, that the bytes inside all septet were unchanged; they retained their first ordering.

Further, if you ran the row-copy code multiple times, the vertical stack of rows you copied would end up being upside down. That’s since the code uses pushes to compose the rows onto the screen. Pushes move the stack pointer toward lesser addresses, and lesser addresses equivalent to display lines higher up on the display.

To visualize the havoc that this row-reversal and septet-swapping would wreak, let’s say that you had the following 28-by-28 tile, representing a key:

If you had used 28 applications of my row-copy code to diagram it onto the screen, you would have ended up alongside this not-a-key:

So . . . that was a problem.

But this problem, too, had an elegant solution!

To review:

• the rows were upside down
• the septets inside all row were swapped
• but the bytes inside all septet were unchanged

The breakthrough was to see “upside down” and “swapped” as two instances of the identical thing. Reversal.

Reversal has this helpful property: it’s an involution. Reverse item twice, and you get rear the original. With this in mind, I justified that if the tiles were pre-processed to reverse their rows and afterward the septets inside the rows, the tiles would end up looking fine whenever they hit the screen. The mangling that occurred during copying and pre-processing would, in effect, undo all other.

Working it out on paper, I additionally discovered that the pre-processing stage could disregard the rows and fair treat the tiles as one long, linear sequence of septets.¹ To see why this is so, let’s regard a small tile of 2 rows of 2 septets each:

+---+---+ | a b | +---+---+ | c d | +---+---+

In memory, it would be laid out in row-major order, that is, as 4 sequential septets:

+---+---+---+---+ | a b | c d | +---+---+---+---+

So, reversing the rows and afterward swapping the septets inside all row is the identical as fair reversing the septet command in memory:

+---+---+ +---+---+ +---+---+ | a b | | c d | | d c | +---+---+ =======> +---+---+ =======> +---+---+ | c d | reverse | a b | toggle | b a | +---+---+ rows +---+---+ septets +---+---+ +---+---+---+---+ +---+---+---+---+ +---+---+---+---+ | a b | c d | | c d | a b | | d c | b a | +---+---+---+---+ +---+---+---+---+ +---+---+---+---+

So the resolution to the mangling issue turned out to be a simple, one-time pre-processing step: Just interrupt all tile into septets and reverse their order.

Knowing that the mangling issue could be solved, I was emotion fine concerning my general idea. I couldn’t see any another problems, so I sketched out a new copy-tile subroutine to current to my friend. Since the row-copy logic was now fair 5 instructions, I used it 4 times, unrolling the sole remaining iteration a bit. Now, alternatively of copying 28 sole rows, I copied 7 quad-rows.

The code looked item akin this:

COPYTILE3 ;;; ;;; Copy a 28x28 display tile into a display buffer. ;;; Arguments: ;;; X = starting location of *septet-reversed* backdrop tile ;;; Y = starting location of destination in display buffer ;;; Execution time: ;;; 34 + 7 * (224 + 7 + 3) + 7 + 10 = 1689 cycles ;;; ;; setup: 34 cycles PSHS U,DP ; preserve U and DP (8 cycles) STS >SSAVE ; preserve S (7 cycles) ;; LDA #TILH/4 ; first quad-row figure (2 cycles) STA >ROWCT ; (5 cycles) ;; LEAS ,X ; initialize src ptr (4 cycles) LEAU (TILH-1)*SCRW+TILW,Y ; initialize dst ptr (8 cycles) ;; @COPY1 ;; copy four rows of 28 pixels in 4 * (48 + 8) = 224 cycles PULS X,Y,D,DP PSHU X,Y,D,DP PULS X,Y,D,DP PSHU X,Y,D,DP LEAU -WOFF,U PULS X,Y,D,DP PSHU X,Y,D,DP PULS X,Y,D,DP PSHU X,Y,D,DP LEAU -WOFF,U PULS X,Y,D,DP PSHU X,Y,D,DP PULS X,Y,D,DP PSHU X,Y,D,DP LEAU -WOFF,U PULS X,Y,D,DP PSHU X,Y,D,DP PULS X,Y,D,DP PSHU X,Y,D,DP LEAU -WOFF,U ;; DEC >ROWCT ; decrease remaining quad-row figure by one (7 cycles) BNE @COPY1 ; iteration during quad-rows remain (3 cycles) ;; LDS >SSAVE ; reconstruct S (7 cycles) PULS U,DP,PC ; reconstruct regs and come back to visitant (10 cycles) SSAVE ZMD 1 ; stash for preservation S during drawing ROWCT ZMB 1 ; var: remaining rows to copy

Adding up the cycles, the total was fair 1689. I had shaved nearly 1200 cycles off of my friend’s code. That’s a 70 percent speed-up!

Beaming, I went to display my friend.

The acidic test

When I caught up alongside my companion and stated I’d figured out how to create the copy-tile regular 70% faster, his visage lit up. When I explained concerning the entire septets-and-mangling thing, though, his visage unlit, doubts rising. But whenever I showed him the code, he got it. It clicked.

“Let’s try it out!” he said.

In concerning a fractional hour’s work, he had the code unified into the game. After a rebuild and reboot, the equivalent was loading.

The heading display came up.

He was into the game.

And . . .

Holy crap!

The equivalent seemed amazingly fast. In truth, it was likely lone a third to a fractional faster, but that was enough. Some crucial perceptual threshold had been crossed. The game-play was now smooth, natural. You could awareness the difference.

We fair sat there, playing the equivalent and grinning. It was a fine day.

But it would not last.

In for a penny . . .

A few days following the speed issue was rearward us – or so we idea – the game’s finishing touches were applied. One of those finishing touches was sampled audio effects. This required feeding byte-sized morsels to the audio-output DAC a few thousand times all second. To agenda the feedings, my companion had turned on a hardware-clocked interrupt.

Worked akin a charm. The appears echoed great, and everything was perfect.

Except for one thing.

After playing into the equivalent one night, we noticed that several of the tiles were getting corrupted. The additional we played, the additional misconduct we saw.

Oh, no.

Something extremely bad was happening.

And afterward it hit us.

What happens if an interrupt goes off during the copy-tile routine?

The processor, to prepared for calling the interrupt handler, would shove its current province onto the scheme stack. But, during the copy-tile routine, there was no scheme stack. The system-stack enroll S had been commandeered. And anywhere was it pointing? Right into the recollection buffer that held the citation tiles!

Oops.

We slumped. After all that effort, to think that our all-important speed-up was causing recollection corruption…

Needing a break, we walked to an all-night diner near evidence to eat and think. Over pancakes and bacon, scrapple and grilled stickies, we talked through the problem.

There were lone two stack registers, and without commandeering the two of them, the copy-tile regular wouldn’t be nearly as fast. There was no way, then, to come back the S enroll to the scheme without losing our hard-won speed. But there was additionally no way that we could get dependable audio without using interrupts.

One way or another, then, interrupts were going to be triggered. And, whenever they were, if copy-tile was running, any S was pointing to was going to get hammered.

“How can we forestall the corruption?” I asked.

We sat there, ignoring our food, the inquiry hanging in the air.

Suddenly, my companion slapped the table. He had it.

“Don’t forestall it!” he said.

“What?” I asked.

“Don’t forestall the corruption,” he explained. “Let it happen. Just not to the citation tiles.”

It was simple, really. He continued:

“Just toggle S and U in the copy-tile routine. U volition item at the citation tiles, and S at the display buffer. If an interrupt goes off, the misconduct volition happen anywhere S is pointing – on the screen. The misconduct volition final lone until we redraw the next frame.”

“That’s brilliant!” I said.

Eager to try his solution, we quickly completed our meal.

. . . In for a pound

Walking rear to the dorms, though, it bothered us that players power see display glitches, equal if for fair a frame. We the two felt that there had to be several way to create the hack perfect, if lone we could discover it.

Later that night, we established it.

Again, it was uncomplicated formerly we saw it. All we had to do was alter the tile ordering. Instead of placing the tiles onto the display from top to bottom, remaining to right, we would go correct to left, base to top. In another words, from elevated addresses to low addresses.

That way, whenever an interrupt went off and corrupted the recollection locations immediately before the tile we were currently drawing, the misconduct would be fixed whenever the extremely next tile was drawn. And since tile-drawing took location in a buffer that wasn’t displayed until it was completely drawn (and the vertical refresh had occurred), nobody would always see the corruption.²

It was the ideal hack!

To the old days!

And that’s the way things were. The difficulty wasn’t overwhelming complexity, as it is today. The difficulty was cramming your ideas into machines so slow, so constricted that most ideas didn’t fit.

You had to bang your ideas around, twist them, rotate them, searching for something, anything that would assistance you compression them into the machine. Sometimes you established it, and you got one stage nearer to realizing your ideas. Sometimes you didn’t.

But the hunt was continually instructive.

In this case, the hunt yielded multiple small victories that, together, solved the problem. But whenever you regard all the things we had to do to create that darn equivalent accelerated enough, it does appear crazy.

We started alongside a tile-copying subroutine whose center was a hand-tuned, unrolled iteration of device instructions. Then, to buy a 70-percent speed-up:

1. We replaced this subroutine alongside a extremely particular manifestation of insanity that commandeered the two stack pointers and used pulls and pushes, and all sole accessible register, to diagram tiles upside downward and horizontally broken.
2. Then we pre-processed the tiles so that example them would really fix them.
3. But afterward – dammit! – interrupts that occurred during example could corrupt the citation tiles.
4. So, to defend the citation tiles, we corrupted the display buffer instead.
5. But that misconduct would be visible.
6. So we changed the tile-placement command to repair – on the fly – any misconduct that power have occurred, before it could always be displayed.
7. And it all worked!

We did that. For 70 percent.

And it was so value it.

Tell ’em if you got ’em

Anyway, I wanted to portion that narrative alongside you for two reasons.

The archetypal is that it’s a fun story. It’s one my earliest memories of struggling alongside a messy computing issue and, through dogged persistence, zeroing in on a resolution that was the two productive and elegant. The outcome was powerfully satisfying.

The struggle, I learned, is value it.

The second logic is to advance you to inform your stories. I cognize that, “back in the day,” most video games likely gave increase to many stories akin this one. I’d affection to comprehend them. But too many of them are lost, having faded out of recollection before anyone idea to maintain them.

If you have a story, delight don’t wait. Tell it. Every day you wait, it gets harder.

Tell it.

Read next

2026.11.03 · All 55 puzzles →

Twelve nodes. Two registers per node. Fifteen lines of code. In TIS-100, equal multiplying two numbers is a small engineering project, and players have spent a decade optimizing these programs on a community community leaderboard. We gave 16 LLMs the equivalent and its manual, withheld the leaderboard, and told them to keep improving.

Within days, players picked up the models’ programs and improved on most of them.

Leaderboard

We ran 16 LLMs, covering foremost frontier and open-weight models. Every example attempted all 47 puzzles in the game, affirmative eight community tournament puzzles, in one scored attempt all (pass@1), alongside 10 to 45 minutes per puzzle, depending on difficulty, to discover a operating program and keep improving it.

RL environments & traces are accessible upon petition for investigation teams. Get in contact ↗

How it works: harness design

Every outcome current is a program we can run and test on caller inputs, which makes a programming equivalent a helpful benchmark. Models get what a participant can inspect, through content tools alternatively of a mouse and screenshots: the manual, apparent test inputs, registers, and equivalent feedback. They don’t get community code or exact records, lone the game’s coarse mark histograms.

Read, edit, runModels peruse the puzzle and tongue reference, edit programs, and run them in the genuine game.

DiagnosticsWrong outputs and deadlocks come back mismatches, registers, and blocked ports, so the next edit can react to evidence.

Saved progressEvery passing program joins the model’s own frontier and can be restored alongside get_best, so a risky edit can’t endure an before result.

RemindersIf a example ends its rotate early, a reminder asks it to keep testing, so quitting first doesn’t decide the score. Reminders merge no resolution hints.

A apparent clockModels see period used against a 10-, 30-, or 45-minute limit. Setup doesn’t count; thinking and equivalent calls do. Models can’t end an event early.

Run limitsGame implementation stops following approximately 1 second without province changes, 5 seconds without output, or 60 seconds overall, and returns diagnostics.

Why test 100,000 inputs? The equivalent checks a small set of cases per run. Our header figure requires a fresh-game replay and 100,000 passing tests on the autonomous TIS-100-CXX simulator, providing stronger evidence that a program generalizes to new inputs.

One document up close

MOV RIGHT, ACC JRO ACC NOP ADD 1 NOP ADD 1 NOP ADD 1 NOP SUB 3 MOV ACC, RIGHT ADD UP MOV ACC, RIGHT MOV ACC, DOWN MOV RIGHT, DOWN

MOV UP, ACC SAV SUB 1 MOV ACC, LEFT NEG ADD 10 MOV ACC, DOWN MOV LEFT, ACC NEG ADD ACC ADD 6 ADD LEFT MOV ACC, DOWN SWP MOV ACC, LEFT

MOV UP, DOWN MOV UP, ACC SAV ADD ACC ADD ACC L: JRO DOWN MOV ACC, DOWN JMP L SWP N: MOV ACC, DOWN M: JRO DOWN JMP N MOV DOWN, DOWN

MOV UP, RIGHT MOV UP, DOWN

MOV LEFT, DOWN

MOV UP, ACC SAV K: MOV 1, UP SUB UP JGZ K MOV 3, UP F: ADD UP JGZ X MOV 1, UP JMP F X: MOV 2, UP MOV ACC, UP SWP SUB UP MOV ACC, DOWN

MOV UP, ACC SAV K: MOV 1, RIGHT SUB RIGHT JGZ K MOV 3, RIGHT F: ADD RIGHT JGZ X MOV 1, RIGHT JMP F X: MOV 2, RIGHT MOV ACC, RIGHT SWP SUB RIGHT MOV ACC, DOWN

MOV UP, ACC SAV ADD ACC ADD ACC L: JRO LEFT MOV ACC, LEFT JMP L SWP N: MOV ACC, LEFT M: JRO LEFT JMP N MOV LEFT, LEFT

Loading puzzle trajectories…

Five models got under the old document in-game. The another two sequence records are GPT-6.1 Sol’s 3,460 on Intersection IdentifierSPEC64160260, against 3,872 (11% faster), and Gemini 4 Argon’s 188 on Error: 8SPEC79324720, against 198 (5% faster). All three are on tournament puzzles, none in the chief game. Of the 133 new frontier points, 18 attack a community document outright. The another 115 are new tradeoffs: improved balances between the three scores than any community solution.

What separates the models

Cost doesn’t track quality

GPT-6.1 Sol reaches 75.6 document proximity at an estimated $0.75 per puzzle. Opus 5.5 reaches 77.2 at $5.08, 7 times the disbursal for 2 additional points. Fable 5.1 is the most costly at $7.19 and scores 70.2.

Loading analysis…

What the models built

We grouped all 55 puzzles by their chief demand, afterward peruse the programs. Fifteen of the sixteen models solved all five routing puzzles, and none established a new frontier item there. The examples below display how distinct designs expend the identical resources.

God mode: what if the example could see the target?

The diagnostics changed what models did next. On Signal Multiplexer22280, GPT-6.1 Sol’s archetypal passing program took 294 cycles. Its overview showed node 2 operating 86% of the period during nodes 1 and 3 spent 84% blocked waiting to compose to it. GPT-6.1 Sol moved the branching out of node 2 and into those two neighbors. The next run took 204 cycles, 31% faster, at a disbursal of two additional nodes and five additional instructions.

Information, tools, and period all changed together, so this study can’t say which supplement helped most. These runs are exterior the chief leaderboard and the header count.

Co-discovery

Pareto explorer

Choose a puzzle and model, afterward choose a item to see its scores and the program that produced it. Every puzzle additionally has its own leaf alongside records and the finest programs: all 55 puzzles.

Download all 3,714 example Pareto points (CSV) · all 3,714 programs (ZIP), additionally on GitHub and Hugging Face. 186 rows are marked as new frontier points, which pond to 133 throughout models.

Methods

Related work

ISA-Bench studies reasoning alongside constrained education sets, including TIS-100. Opus Magnum Bench tests agents’ capability to build and optimize machines in another Zachtronics game. We concentration on optimization throughout all TIS-100 puzzles and eight community puzzles, keeping tradeoffs throughout cycles, nodes, and instructions. The tasks and protocols differ, so scores aren’t immediately comparable.

Cite

@misc{wincon2026tis100bench, heading = {TIS-100 Bench: LLMs Push the Pareto Frontier in Programming Puzzle Games}, author = {{Wincon}}, twelvemonth = {2026}, duration = nov, url = {https://tis-100.wincon.dev/}, note = {Benchmark snapshot 2026-11-03-v5} }

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Google has misplaced again in SerpApi's abrasion lawful combat in court, alongside the court giving Google 21 days to amend its complaint. But this is a important win for SerpApi and this case seems akin it power be coming to a near soon.

As a reminder, Google submitted a lawsuit against SerpApi complete abrasion its hunt results. That lawsuit was dismissed, so Google submitted an amendment of the lawsuit about the idea of protecting licensed satisfied inside its hunt results.

The fairness ruled in favor of SerpApi on its motion to disregard Google's revised complaint. Importantly, the fairness did not regulation that SerpApi's abrasion practices are lawful. The ruling is chiefly concerning whether Google provided adequate actual allegations to established claims under the Digital Millennium Copyright Act (DMCA).

However, Google has another chance to amend its grievance and try again by November 30, 2026. Here is what happens next:

• Google must accurate the deficiencies identified by the judge.
• Google must present a redline showing changes from its former complaint.
• SerpApi afterward has 21 days to respond.
• Discovery remains on clasp during the revised grievance and any new dismissal motion are resolved.
• If Google does not amend inside the permitted period, the case volition be dismissed alongside prejudice.

This is a procedural triumph for SerpApi, but possibly a strategically crucial one. The court is demanding a much additional exact lawful basis for using the DMCA against automated scraping. The next revised grievance volition be particularly crucial since it volition display whether Google can provision the missing licensing, copyright ownership, and content-specific details.

The complete ruling is in this PDF.

Meanwhile, it seems Google is doing a fine job preventing a lot of these scrapers from abrasion in another ways.

Forum conversation at X.

In April of 2023, the FBI took downward an invite-only dreary web market called Genesis Market. The capture was part of “Operation Cookie Monster,” a DOJ collaboration alongside law implementation agencies throughout 17 countries. They discovered 80 myriad taken credentials from about 1.5 myriad devices, including meeting cookies that let scammers log into a user’s document without equal entering a password. 

Genesis Market may be gone, but bundles of leaked meeting cookies called “stealer logs” are motionless harvested and sold in another dreary web spaces. In fact, NordVPN researchers counted additional than 52.4 milliard taken cookies in infostealer data between June 2025 and 2026. That said, the fine news is that taken meeting cookies halt operating as shortly as you revoke energetic sessions from your document settings. As such, it's crucial to discover out if your meeting cookies ended up on the dreary web, remediate your document if necessary, and evade specified leaks in the archetypal place.

What makes browser sessions so valuable?

Every period you successfully log into an account, the website hands your browser a small content document called a session cookie. Inside the content document is a distinctive meeting ID that lets the website immediately acknowledge you for as lengthy as you’re logged in. That way, you don’t have to keep entering your login credentials all period you navigate to a new leaf or create a caller petition on that website. 

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Session cookies typically arrive alongside an expiration duration that ranges from a few hours to multiple weeks, at the end of which you’re logged out and have to re-enter your credentials again. But the capture is, if person alternatively gets their hands on your meeting cookies, they can piggyback off of that logged-in meeting by pretending to be you. 

To accomplish this, hackers use a category of malware called infostealers, which includes infamous names akin Lumma, Vidar, StealC, Acreed, and Atomic Stealer (AMOS). They create their way onto your equipment through infected websites, pirated software, and counterfeit installers. Once in, they quietly spy on your activities to extract passwords, PINs, autofill data, and meeting cookies—all of which goes into a document called a stealer log that’s delivered direct to the hacker. 

Once a hacker has admission to these stealer logs, they can either market them or use them for themselves. Either way, as shortly as person imports those logs into their browser, they can efficiently obtain complete your logged-in accounts using those meeting cookies from your device. They can equal use that opening to log you out and reset your passwords. 

How stealer logs get sold on the dreary web

There’s a extremely organized dreary web provision sequence that attackers use to commerce in stealer logs. Russian Market has efficiently replaced Genesis Market as the new storefront for dreary hat cybercriminals, although much of the market has additionally shifted to personal channels on Telegram.

According to danger analysts at DarkOwl, about 180,000 stealer logs were sold on Russian Market in fair the archetypal fractional of 2025. What's more, Russian Market is a well-designed storefront that users can admission equal without Onion links or the Tor browser. That method anyone could go there and buy a bunch of stealer logs to commencement attempting document takeovers at scale. 

Meanwhile, Flare Research estimates that this isn’t equal near to the genuine measure of the threat, since 90% of stealer logs now exterior privately on Telegram. There, automated chatbots let scammers shop for stealer logs akin it’s Amazon, alongside options to display by country, app, and document privilege. Logs market for anyplace between $5 and $500 a piece, depending on the estimated value of the mark accounts. 

How to inspect if your meeting cookies have leaked

There isn’t one sole repository that keeps track of all taken biscuit or credential, but there are a few consumer-friendly ways to inspect if you’re emotion doubtful that your document has been compromised. More options be for endeavor users who can oversee to expend hundreds or equal thousands of dollars a duration in subscriptions to keep track of dreary web threats, but those are mostly overkill for regular users. 

The easiest way to go concerning this is to obtain a appearance through all your energetic devices and their locations in your document settings on most websites. If you see a equipment or location you don’t recognize, you are apt the topic of an ongoing breach. However, keep in intellect that this may not continually be a dependable method if you use iCloud Private Relay or a VPN. Still, it's mostly finest custom to log out of all energetic sessions all formerly in a during and execute a caller login to invalidate any unauthorized sessions.

Secondly, Have I Been Pwned is a liberated assistance that tracks taken credentials throughout important dreary web forums and markets. It doesn’t really track meeting cookies, but if your email location or password ended up in a breach, it’s harmless to say that they likely have your meeting cookies too. You can equal sign up for notifications so you get alerted the instant one of your accounts shows up in a data leak. While there aren’t many consumer-focused dreary web monitoring tools that track meeting cookies, NordVPN's Complete or Prime plans contain a real-time monitoring assistance for hijacked sessions that actively scans the dreary web for leaks that power power you. 

What to do if your sessions are compromised

Now that we’ve covered detection, let’s conversation concerning what to do whenever you’ve confirmed that your meeting cookies are taken and you’re the casualty of an ongoing breach. Remember, the command in which you prosecute the steps below matters. If you do them in the incorrect sequence, that’ll provision attackers all the chance they need to obtain complete your accounts again following you’re done.

1. Begin by operating a complete antivirus scan on any devices you own. Attackers can’t get their hands on your meeting cookies unless they infect your equipment first. Remove any malware that your antivirus flags during the scan, afterward do a spotless instal of your functioning scheme if you can spare the time. 

2. Reset the passwords on your email account, allow two-factor authentication for added protection, and sign out of all sessions before doing a caller login. Your email inbox is the sole item of admission for most attacks since that’s anywhere most websites dispatch their verification codes or magic links. 

3. Sign out of all energetic sessions on all document that you doubtful is compromised. This volition log out any attackers who are currently on a hijacked browsing session. 

4. Change your passwords on all phase in command of priority. Start alongside banking websites, haze retention providers, and password managers first. 

5. Look through all compromised account’s third-party integrations and app permissions. Revoke admission if you can’t acknowledge an app, or it looks suspicious. Also create certain to rotate any API keys that you’re currently using, since those may have been compromised as well. 

Reducing safety hazard from meeting cookies

While there’s no foolproof way to keep your browser sessions harmless for now, that power shortly alter alongside the Device Bound Session Credentials (DBSC) initiative. This is an open-web norm that volition efficiently fastener all logged-in online meeting alongside a personal key protected by your computer's safety chip, so that attackers can’t use meeting cookies to impersonate you from a distinct device. Google has already implemented DBSC on Chrome for Windows and Google accounts; Chrome users on macOS are additionally getting admission to this characteristic gradually. 

But during the undertaking has already been open-sourced, no another important online provider has begun offering native assistance for it as of this article. That method DBSC’s safety benefits are constricted to Google services akin Gmail and Docs, Chrome for Windows, and third-party websites that recommendation sole sign-on (SSO) options for your Google account. We power see a wider rollout in the near future, though. 

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There are many reasons why person power use a VPN, but most often, it’s to conceal your genuine geographic location or forestall websites from tracking your online activity. It can additionally be a way to get about location-based restrictions that halt you from accessing certain websites or platforms. 

When you nexus to a VPN server in the United States, websites are expected to detect that your online traffic is originating from the U.S. That way, you can admission online platforms that use IP filters to obstacle non-U.S. traffic or circumvent local censorship whenever travelling exterior the U.S. But if you nexus to a VPN server in the United States during you’re vacationing in Mexico, and a website thinks your IP location is from Brazil, that power not resolve your issue and may equal add unnecessary complications. 

If you’ve encountered item akin alongside your VPN provider, there are multiple fixes you can try. Depending on why your IP location is being misinterpreted, one of these should assistance you admission the net from the server location of your choice. 

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Some websites neglect to peruse your accurate IP location whenever you're using a VPN service. Credit: Surfshark

Why websites misread your VPN location

IP geolocation isn’t infallible. Websites depend on third-party IP databases to appearance up your location according to your current IP address. Maxmind, which has among the largest specified databases in existence, claims that its GeoIP products have a 99.8% accuracy. Lesser-known providers alongside smaller IP databases may be far small accurate. 

Websites can additionally use additional than fair your IP location to evaluation your location. For example, they can dispatch WebRTC requests to your browser or immediately query your device’s GPS. Moreover, VPN providers frequently have bodily servers in one nation during their IP addresses are registered to another country, and this discrepancy can additionally create issues. Let’s obtain a nearer appearance at all of these problems individually, so you can discover the fix that plant finest for you. 

WebRTC leaks disclose your genuine IP address

WebRTC is an open-source innovation that lets your browser decrease latency whenever busy in high-bandwidth tasks akin streaming or video calls. Based on the IETF norm RFC 8828, it lets a website choose between your VPN server and your genuine IP location so it can established the quickest way to transmit ample amounts of data and decrease delay times or buffering. 

But the capture alongside WebRTC is that it exposes both your VPN server and ISP-assigned addresses to websites, which can disclose your genuine IP location and logic websites to refuse your VPN server country. Firefox now comes alongside built-in protections to forestall WebRTC leaks, during Chrome and Edge assistance third-party extensions akin WebRTC Control that you can use to eliminate these issues. To inspect if your browser is leaking your genuine IP location during WebRTC requests, you can use a liberated tool akin BrowserLeaks.

DNS lookups item to the incorrect country

Even whenever a browser isn’t leaking your genuine IP address, DNS resolvers may fetch inaccurate location data if their nearest servers are too far from your current location. For example, a user in São Paulo may be geolocated to Chile whenever using Google Public DNS since that’s anywhere Google’s nearest resolvers are located. 

If you toggle on DNS leak safety in your VPN app, this volition power websites to use your VPN’s resolver to execute DNS lookups. That frequently solves the problem, but, again, you can verify the fix worked through a assistance akin BrowserLeaks or IPLeaks.

Outdated databases item to incorrect locations

Websites depend on IP databases akin Maxmind, IP2Location, IPinfo, etc. to appearance up your exact location, but these databases get outdated quickly and need changeless updating. Most of these databases additionally accurate errors on request, but that takes several time. Also, all website has its own rules for how frequently it queries IP databases for updates.

Even whenever locations are updated in the genuine database, a website may be sitting alongside outdated data unless it actively has refreshed it recently. MaxMind recommends doing this at smallest twice a week, but that’s ultimately up to the particular website.

Virtual servers don’t equivalent their bodily location

VPN providers frequently depend on virtual servers that use IP addresses registered in a distinct area than the server’s bodily location. For example, ExpressVPN notes that it serves IP addresses in Bolivia, Ecuador, Peru, Uruguay, and Venezuela through servers located physically in Brazil. 

While this is normally to assistance alongside the deficiency of local infrastructure or strict surveillance laws in the region, many databases and analytics tools volition emblem the discrepancy for websites, foremost to disturbance and inconsistency concerning your genuine server location. In these cases, your finest bet is to toggle your VPN server or use a dedicated IP location by signing up for a paid add-on for your VPN.

You can run a liberated scan on your browser to detect your current IP address, geolocation, and servers. Credit: IPConfig.co

How to inspect for IP location mismatches for free

Before investing in a particular solution, it’s improved to do a thorough lookup to create certain why your IP location is pointing to the incorrect location and whether a WebRTC or DNS issue, virtual servers, or item alternatively is the cause. Here’s how I’d go concerning it, stage by step: 

1. We’ll commencement by record your baseline IP address, country, city, and ASN. With your VPN disconnected, navigate to IPConfig.co on your browser to catch your default IP details. I akin this tool since it’s liberated and uses echoip to drag your location data direct from Maxmind. If you favor using Terminal alternatively of your browser, you can additionally run curl ifconfig.co/json to catch these particulars in plain content format.

2. Now nexus your VPN server. Then sojourn IPConfig.co again to note downward the changed details. 

3. Make certain the Country and Timezone fields equivalent your current VPN server location. Also create certain the ASN (organization) site does not catalog your residence ISP.

4. In case these particulars do not equivalent your VPN server, run a WebRTC leak test and a DNS leak test using BrowserLeaks. If either of these tests doesn’t come back your VPN server’s IP address, you’ve established your culprit.

5. If the two the leak tests arrive rear spotless but a particular location motionless gets your location wrong, the matter is apt originating from an outdated repository or virtual server. 

There’s no surefire way to resolve IP location mismatches for good. But if it happens frequently adequate to disrupt your net use, you can regard switching to a distinct VPN server and getting a browser add-on that prevents WebRTC leaks. If that doesn’t work, I’d regard purchasing a dedicated IP location that isn’t according to a virtual server. While many IP databases akin MaxMind or IP2Location additionally have ways to petition a location correction, that takes a during to go through and isn’t value the attempt unless it’s a imperishable IP location registered through your ISP.

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If you're thinking of picking up any big-ticket items soon—whether for yourself or as a current for person on your list— I would advise you to delay until you see what retailers have in shop for the holiday revenue season, which volition boot off in earnest in mid-November. Walmart is the archetypal important retailer to province its Black Friday and Cyber Monday scheme for 2026, and they really affect three important buying events between now and the December holidays.

What is Walmart doing for Black Friday and Cyber Monday in 2026?

As it did in 2025, Walmart volition clasp three revenue between Nov. 12 and Dec. 2, as outlined in a recent media release. The revenue volition be the two online and in-store, and volition mark a mix of Walmart+ members and broad shoppers.

When are Walmart's Black Friday and Cyber Monday revenue in 2026?

The events volition obtain location on three distinct dates:

Walmart's Black Friday Deals Event 1: Nov. 12–15

• Available online and in stores starting at 6 a.m. local time

• Walmart+ members get six hours of first admission commencement online at 12:01 a.m. ET on November 12

Walmart's Black Friday Deals Event 2: Nov. 23–29

• Online only: Nov. 23 starting at 12:01 a.m. ET

• Online and in stores: Nov. 27 starting at 6 a.m. local time

• Walmart+ members get six hours of first admission online commencement Nov. 23 at 12:01 a.m. ET

Walmart's Cyber Monday Deals Event: Nov. 30-Dec. 2

• Online only

• Event begins at 12:01 a.m. ET

What period does Walmart open on Black Friday?

Walmart's bodily stores volition open at 6:00 a.m. local period on November 27 for their Black Friday events. Of course, they volition commencement online earlier, so create certain to inspect their website as well.

What volition be on transaction during Walmart's Black Friday and Cyber Monday sales?

Walmart says that you can anticipate discounts on electronics, toys, fashion, beauty, residence goods, gifts, and mundane essentials. Although the business doesn't provision much in the way of specifics in its media release, final year's revenue included discounts on TCL TVs, Dyson vacuums, Dreo appliances, and toys from LEGO.

What are several first Black Friday deals value checking out correct now?

Walmart already has plenty of fine deals out early. You don't need to delay for the authoritative transaction to commencement to discover several products going for their lowest prices ever. Here are several of the finest ones I've established so far:

Apple AirPods 4

$89.00 at Walmart

$129.99 Save $40.99

Get Deal

Get Deal

$89.00 at Walmart

$129.99 Save $40.99

BISSELL Little Green Portable Deep Cleaner

$74.62 at Walmart

$101.97 Save $27.35

Get Deal

Get Deal

$74.62 at Walmart

$101.97 Save $27.35

DAYBETTER 7.5ft Artifical Christmas Tree

$122.99 at Walmart

$189.99 Save $67.00

Get Deal

Get Deal

$122.99 at Walmart

$189.99 Save $67.00

Beats Studio Pro Wireless Headphones - Matte White

$149.00 at Walmart

$299.00 Save $150.00

Get Deal

Get Deal

$149.00 at Walmart

$299.00 Save $150.00

NYXI Hyperion 3 Wireless Joypad alongside Hall Effect Joystick for Switch 2

$79.99 at Walmart

$118.99 Save $39.00

Get Deal

Get Deal

$79.99 at Walmart

$118.99 Save $39.00

Samsung 65” Class M70HB Series Mini LED 4K UHD Samsung Vision AI Companion Smart Tizen TV 2026

$378.00 at Walmart

$478.00 Save $100.00

Get Deal

Get Deal

$378.00 at Walmart

$478.00 Save $100.00

JBL Charge 6 - Portable Waterproof and Drop-Proof Bluetooth Speaker

$149.95 at Walmart

$199.95 Save $50.00

Get Deal

Get Deal

$149.95 at Walmart

$199.95 Save $50.00

Samsung 27" Odyssey G55C QHD 165Hz 1ms Curved Gaming Monitor, 4.7 in Depth

$159.00 at Walmart

$199.00 Save $40.00

Get Deal

Get Deal

$159.00 at Walmart

$199.00 Save $40.00

Alienware Aurora 16" WQXGA 120Hz Gaming Laptop, Intel Core 7-240H, NVIDIA RTX 5050, 16GB RAM, 512GB SSD, Windows 11, Blue, AC16250

$1,099.00 at Walmart

$1,999.99 Save $900.99

Get Deal

Get Deal

$1,099.00 at Walmart

$1,999.99 Save $900.99

AirPods Max 2 - Orange

$479.00 at Walmart

$549.00 Save $70.00

Get Deal

Get Deal

$479.00 at Walmart

$549.00 Save $70.00

SEE 7 MORE

Do I need Walmart+ for these deals?

No. But if you are a Walmart+ member, you'll get first admission to the sale. You can sign up for a liberated 30-day Walmart+ subscription and cancel it afterwards or get the annual scheme for $98 ($8.17/month).

Are Walmart’s Black Friday deals online lone or additionally in stores?

Deals volition be the two online and in the bodily stores. There power be deals online that you won't see in-stores and vice versa.

What another retailers are holding Black Friday sales?

The holiday period volition see important revenue from the identical catalog of retailers that vie for your dollars throughout the year—namely, Best Buy, Target, and Amazon. Each volition have its own type of Black Friday and Cyber Monday sales. So far, lone Walmart has revealed its plans.

Are Black Friday and Cyber Monday deals value it?

In short, yes. Though they aren't fairly as impactful as they formerly were, Black Friday and Cyber Monday revenue recommendation discounts that can be rare throughout the remainder of the year. Whether it's a important acquisition you've been preservation up for or you’re buying for gifts, it’s a fine period to appearance for discounts, particularly on items akin appliances and electronics. Last year's revenue included categories specified as tech, home improvement, and fitness.

Are Cyber Monday deals improved than Black Friday deals?

Black Friday used to be whenever important retailers offered their finest deals on costly tech and appliances, during Cyber Monday was for cheaper tech and gave smaller businesses a chance to vie online. Now, however, the difference is nearly meaningless: Every important retailer offers revenue on the two days, which method the astute move is to cognize what you want, use cost trackers to detect the deals, and mention to our Black Friday coverage, anywhere we do all the searching, curating, and price tracking for you.

// how it works

Hidden in plain HTTPS.

A censor observing the cable sees average web traffic on harbor 443. No tell-tale handshake, no blockable fingerprint. If they investigation the server, it answers akin a normal website.

// transport

Many flows.
One association shape.

One TLS association per stream method hundreds of parallel sessions under load: dilatory to establish, and a form value flagging. Pooled multiplexing carries all stream complete a fistful of long-lived connections, so the cable stays small and average no matter how occupied you are.

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Terence Tao · original page

In Six Math Essentials, the renowned mathematician and Fields Medalist Terence Tao introduces readers to six chief concepts that have guided mathematicians from antiquity to the frontiers of what we cognize today and now assistance us create awareness of our complex world. This slim, elegant quantity explores numbers as the gateway to quantitative thinking; algebra as the gateway to abstraction; geometry as a way to compute beyond what we can see; probability as a tool to navigate doubt alongside rigorous thinking; inspection as a method to tame the extremely ample or the extremely small; and dynamics as the math of change.

• Publisher (Quanta Books)
• Publisher (Farrar, Straus and Giroux)
• Publisher (Pelican, UK edition)
• Sample excerpt: the algebra division (Science Friday, October 30, 2026)
• Review by Karmela Padavic-Callaghan (New Scientist, October 21, 2026)
• Review (Publishers Weekly)
• Review (Library Journal)

No errata have been recorded for this book.

Approved July 2, 1890, The Sherman Anti-Trust Act was the archetypal Federal act that outlawed monopolistic endeavor practices.

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He made billions betting on what’s next. Now this 71-year-old investor’s latest move reflects his condemnation that AI volition alter how the Internet works.

Vinod Khosla’s project chief firm, Khosla Ventures, made early investments in OpenAI, DoorDash and Instacart. His latest investment, AI startup Coframe, targets another possible shift: how websites operate. Coframe wants to rewire the Internet so all visitant to a website sees a leaf custom-made for them.

“The earth has changed since AI has enabled extreme customization,” Khosla stated in an interview alongside Business Insider. Forbes reported before this twelvemonth that Khosla’s net value is about $10 billion.

Coframe announced this week that it raised $35 million in total funding, including a $25 myriad Series A led by Khosla Ventures and Hanabi Capital. Executives at Anthropic, OpenAI and Google DeepMind additionally participated.

Coframe helps businesses improve their websites so additional group buy something, sign up for item or obtain another desired action. The startup creates and tests distinct versions of a webpage, including text, images and design. It afterward tracks how visitors engage alongside the webpage to decide how to enhance it.

For example, say an online shop wants to market additional shoes. Coframe could assistance the business test distinct headlines, merchandise images or leaf layouts and decide which versions guide to additional purchases.

“For decades, the web has been icy in place, showing all visitant basically the identical page,” Khosla stated in the press release. “Coframe is construction the living internet, anywhere two group can sojourn the identical website and have entirely distinct experiences, personalized to who they are and what they need. These interfaces continuously study and enhance themselves. This is a huge leap beyond traditional A/B evaluation and the next repeat of the internet.”

Coframe’s results

Coframe claims that it can assistance businesses get additional out of the visitors they already have and expend far small period figuring out how to capitalize on their audiences. The startup stated in the media publish that its AI-powered evaluation platform has helped customers create additional than $300 myriad in additional revenue, alongside conversion rates improving by additional than 20% on average.

Coframe’s customers contain Dropbox, BCG, Block, Backcountry and Sur La Table.

Speed is another part of the startup’s appeal. Coframe stated it built and launched an test for Dropbox in 30 minutes that earlier would have required four weeks of engineering, scheme and quality-assurance work. For an unnamed Fortune 500 customer, the business stated it launched dozens of variations and risen conversions by 70% inside 30 days of the agreement being signed.

The idea is to let businesses try additional approaches without adding weeks of manufacturing activity all time. Faster evaluation can assistance teams acknowledge promising changes and move former unsuccessful ones sooner.

Khosla sees AI as a way to provision an experience built about all visitant to a website, akin Coframe is doing.

“The substitute is to compose code for all leaf that’s presented, but that’s too costly and way too slow,” Khosla told Business Insider. “This idea of a tailored leaf for all person is a really fine idea.”