Hardware concurrency

The reading takes one line and needs no permission. What makes it useful to a site is that the same number can be asked for in several places at once.

• Reads it in the document

  The plain reading, taken as the page loads and stored next to everything else it collected.

• Asks a background thread

  A worker reports the same property. Two answers that differ say more about the browser than either number does.

• Asks an embedded frame

  A frame is a third place to ask, and a value changed in the document alone does not reach it.

• Sizes its own work by it

  Pages split heavy work by the count they were given, so the number also has to be plausible for the machine doing the work.

These values are read in your browser on this page. They are the three a site reads together when it wants to know what kind of machine you are on.

A core count is believable or not only next to the graphics card. Integrated laptop graphics of one generation top out at eight threads, so sixteen cores beside them describe a machine that was never built.

Apple chips are stricter still. The count is set by the chip rather than chosen: the plain generations report eight, the larger ones ten or twelve, the largest fourteen or sixteen.

• The card decides the range

  Every card the app can claim carries the core counts machines with that card actually report.

• The pair is read first

  Processor next to graphics is among the first things a defence system compares, and an impossible pair is louder than any single value.

• The memory figure joins them

  Cores, memory and the card are one description of one machine, and all three are drawn from the same profile seed.

The count arrives as one seed on the launch line, before the first line of page code runs, and it is drawn from the counts that fit the card the profile was given.

It answers the same in the document, in a frame and in a background thread, because the engine reports it in one place for all three.

1. 1

   The editor offers what the generator gives

   The list is derived from the same pools, so a profile the app made never shows an empty slot in its own card.

2. 2

   A count that does not fit is refused

   Save a hand-picked count that contradicts the card and the field is named as refused rather than quietly applied.

3. 3

   An old edit is left alone

   The check runs when you save, not at launch, so a profile that has walked around with a value for months does not change machine.

Three measurements from the acceptance run of the build shipping today, on a Windows profile whose seed asked for eight.

• The document reported the seed

  Measured on a build host with a different processor to the one the profile claims.

  8

• The frame and the thread agreed

  Both were asked for the count and the platform, and both answered as the document did.

  same in all three

• The population holds several counts

  Across four hundred generated profiles more than two counts appear, so the number alone links no profile to another.

  more than two

The panel above shows what this browser reports. The free check on this site puts the count and the memory figure on one row, which is how a site reads them.

Inside the app the self-test runs in a profile against the engine that profile launched. It compares the count to the seed and then asks a frame and a background thread the same question.