OK, I've now gathered more information about it, still some holes but I can draw a fairly complete picture about it 
The prehistory of it teaches us that as soon as 1936, Bosch GmbH filed a patent on a "device that prevents wheel lock while braking", and in fact they've been working on such systems ever since this date.
But Dunlop beat them to it for a good reason: this was WWII and they had an immediate need for this kind of device: aircrafts landing on aircraft carriers. They needed such a system to avoid aquaplanning. Thus they created the system called Maxaret, an entirely mechanical ABS system. And this same system was applied in a production car in 1966, the Jensen FF (and as another first, it was also the first production car ever to be 4WD!).
Done with the prehistory, now let's see the history: electronic ABS. This was first created by Bosch and they had it ready for 1970. Ready, but not reliable, it took them no less than 8 years to get it right, and it was then proposed as an option on the Mercedes S Class, and a year later on the BMW 7 Series. Since then it gained more functions, and more importantly maybe a sturdier build and lots of weight, but in the good direction: while ABS 2 (the first production ones) weighed 6.3 kgs and had 140 components in the control unit, the newest one (ABS 8.0), unleashed in 2001, weighs only 1.6 kg with 10 components in the control unit, and all this by achieving much, much more, quicker, better.
A modern ABS as we know it is made of:
* the control unit - all the electronic stuff;
* the hydraulic unit - to operate brakes;
* wheel sensors;
* a yaw/lateral acceleration sensor;
* a steering wheel angle sensor;
* a brake pedal sensor;
* an acceleration pedal sensor.
Its functions are:
* ABS (of course);
* EBD (Electronic Brakeforce Distribution);
* CBC (Cornering Brake Control);
* BAS (Brake Assist System);
* TCS (Traction Control System);
* ESP (Electronic Stability Program)
So let's see how this all works.
The ABS itself
The control unit (I'll call it CU) is nothing but a program on EEPROM, therefore it can be modified, and along the data which can be modified, apart from the operating stuff, is a table of wheel spin thresholds according to its speed. Thresholds are defined for speed intervals, not every discrete speed, but of course, the more thresholds there are means the smaller the interval and the higher the number of definitions, therefore the better.
So, first, the ABS knows that you're braking because of the brake pedal sensor and knows your speed, v, by reading the wheel sensors. It then looks for the interval which matches that speed, reads the threshold values, say a and b, and knows that at the next read out of this sensor it SHOULD read a speed between v-a and v+b. It does this for all 4 wheels, of course.
Well, you can see where this is going:
* if the speed is less than v-a, then the ABS supposes that the wheel is about to lock. Therefore it orders the hydraulic unit to release the brake pressure on that particular wheel;
* on the other hand, if speed is more than v+b, then the wheel needs to be braked some more. Hydraulic unit, make your job. The end.
It should be noted that it's therefore possible to program a completely useless ABS if you define absurd thresholds! If they're too high, you will get wheel lock, if they're too low, you may not be braking at all... In theory, the ABS should be reprogrammed every time you change tires or brake components! Fortunately you don't need to
EBD
This is and added logic to the basic ABS functionality: in braking situations, if a rear wheel is about to lock, in addition to ordering a pressure release on the given wheel, it will also order a pressure increase on the corresponding front wheel. Therefore no need for mechanical braking distribution anymore, it works whatever the load you have on your rear axle.
CBC
Some more added logic here: since you're braking while cornering you need more braking on the wheels which are outside the curve. Detecting this situation by reading the steering angle sensor, the CU will therefore order more braking force to the outside wheels and less to the inside wheels.
BAS
ABS, when it operates, makes for pulsations into the brake pedal, everybody has experienced that (well, except when you have brake by wire but that's another story). Unfortunately, the common reaction in this case is the wrong one, that is releasing the brake pedal. So, when the CU detects an emergency braking situation, it counters the human reaction by ordering full braking force. You can feel this by feeling the brake pedal "sink". Only when the brake pedal is fully released the CU considers that this is no more an emergency situation.
There are two different operation modes for this function: either mechanical, in which case it triggers after a certain level of braking, or electronic, in which case it triggers after detecting a swift enough acceleration applied to the brake pedal.
TCS
ABS reversed here! Another set of thresholds for accelerating (which the CU detects by, guess what, the acceleration pedal sensor), except that of course there's only one value in the table here. Out of threshold, brake offending wheel. As an added difference though, if both wheels are out of threshold and braking is not enough, in order to avoid excessive transmission strain, the CU can order the engine to lose power.
ESP
The final function here. Data collected, apart from your speed, is the steering angle, yaw and lateral acceleration. The role of ESP will be to make the car go where *you* want it to go, by braking individual wheels and cutting engine power if this is not enough.
And there's my big hole, I need to clarify to myself what wheels in which situation
The prehistory of it teaches us that as soon as 1936, Bosch GmbH filed a patent on a "device that prevents wheel lock while braking", and in fact they've been working on such systems ever since this date.
But Dunlop beat them to it for a good reason: this was WWII and they had an immediate need for this kind of device: aircrafts landing on aircraft carriers. They needed such a system to avoid aquaplanning. Thus they created the system called Maxaret, an entirely mechanical ABS system. And this same system was applied in a production car in 1966, the Jensen FF (and as another first, it was also the first production car ever to be 4WD!).
Done with the prehistory, now let's see the history: electronic ABS. This was first created by Bosch and they had it ready for 1970. Ready, but not reliable, it took them no less than 8 years to get it right, and it was then proposed as an option on the Mercedes S Class, and a year later on the BMW 7 Series. Since then it gained more functions, and more importantly maybe a sturdier build and lots of weight, but in the good direction: while ABS 2 (the first production ones) weighed 6.3 kgs and had 140 components in the control unit, the newest one (ABS 8.0), unleashed in 2001, weighs only 1.6 kg with 10 components in the control unit, and all this by achieving much, much more, quicker, better.
A modern ABS as we know it is made of:
* the control unit - all the electronic stuff;
* the hydraulic unit - to operate brakes;
* wheel sensors;
* a yaw/lateral acceleration sensor;
* a steering wheel angle sensor;
* a brake pedal sensor;
* an acceleration pedal sensor.
Its functions are:
* ABS (of course);
* EBD (Electronic Brakeforce Distribution);
* CBC (Cornering Brake Control);
* BAS (Brake Assist System);
* TCS (Traction Control System);
* ESP (Electronic Stability Program)
So let's see how this all works.
The ABS itself
The control unit (I'll call it CU) is nothing but a program on EEPROM, therefore it can be modified, and along the data which can be modified, apart from the operating stuff, is a table of wheel spin thresholds according to its speed. Thresholds are defined for speed intervals, not every discrete speed, but of course, the more thresholds there are means the smaller the interval and the higher the number of definitions, therefore the better.
So, first, the ABS knows that you're braking because of the brake pedal sensor and knows your speed, v, by reading the wheel sensors. It then looks for the interval which matches that speed, reads the threshold values, say a and b, and knows that at the next read out of this sensor it SHOULD read a speed between v-a and v+b. It does this for all 4 wheels, of course.
Well, you can see where this is going:
* if the speed is less than v-a, then the ABS supposes that the wheel is about to lock. Therefore it orders the hydraulic unit to release the brake pressure on that particular wheel;
* on the other hand, if speed is more than v+b, then the wheel needs to be braked some more. Hydraulic unit, make your job. The end.
It should be noted that it's therefore possible to program a completely useless ABS if you define absurd thresholds! If they're too high, you will get wheel lock, if they're too low, you may not be braking at all... In theory, the ABS should be reprogrammed every time you change tires or brake components! Fortunately you don't need to
EBD
This is and added logic to the basic ABS functionality: in braking situations, if a rear wheel is about to lock, in addition to ordering a pressure release on the given wheel, it will also order a pressure increase on the corresponding front wheel. Therefore no need for mechanical braking distribution anymore, it works whatever the load you have on your rear axle.
CBC
Some more added logic here: since you're braking while cornering you need more braking on the wheels which are outside the curve. Detecting this situation by reading the steering angle sensor, the CU will therefore order more braking force to the outside wheels and less to the inside wheels.
BAS
ABS, when it operates, makes for pulsations into the brake pedal, everybody has experienced that (well, except when you have brake by wire but that's another story). Unfortunately, the common reaction in this case is the wrong one, that is releasing the brake pedal. So, when the CU detects an emergency braking situation, it counters the human reaction by ordering full braking force. You can feel this by feeling the brake pedal "sink". Only when the brake pedal is fully released the CU considers that this is no more an emergency situation.
There are two different operation modes for this function: either mechanical, in which case it triggers after a certain level of braking, or electronic, in which case it triggers after detecting a swift enough acceleration applied to the brake pedal.
TCS
ABS reversed here! Another set of thresholds for accelerating (which the CU detects by, guess what, the acceleration pedal sensor), except that of course there's only one value in the table here. Out of threshold, brake offending wheel. As an added difference though, if both wheels are out of threshold and braking is not enough, in order to avoid excessive transmission strain, the CU can order the engine to lose power.
ESP
The final function here. Data collected, apart from your speed, is the steering angle, yaw and lateral acceleration. The role of ESP will be to make the car go where *you* want it to go, by braking individual wheels and cutting engine power if this is not enough.
And there's my big hole, I need to clarify to myself what wheels in which situation
