Chess-oriented crossword: intermediate

Answers so far:

Across: 5.Perpetual,6.Oll,9.Chaturanga,12.Shredder

Down: 1.Bishop,2.Topalov,3.Epaulette,4.HAL, 7.Cambridge,8.Breakthrough,9.Carlsen,10.Hydra,11.Phalanx

1 down Bishop

7 d Cambridege

11 d phallanx

5 a discovery?

 All correct except for 5!

2d Topalov

3d epaulette

9a chaturanga

 Correct!

5 across is perpetual.

4 down Tao?

9 down is Carlsen.

6a Oll

12a Shredder

6 across is Oll. 

Good going guys, 4 down is not Tao though.

10 down is Hydra.

Only 4 down and 8 down are unsolved.  Tao is a chess engine and fits, do I get
half credit?

Hints:

4 Down: think of a famous sci-fi movie

8 Down: you breach your opponents defences...

10 Down: evaluates 200,000,000 chess positions per second

4 down Sam?

Elf is a three-letter chess engine but it doesn't fit.

No....

4 down is Hal.

Second letter is "A."