grid deduction - Double feature: Computer problems

_{This puzzle is part 11 of the Double feature series (first part here). The series will continue in "Double feature: Bibliophile edition".}

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Rules of Statue Park¹

• Insert eleven of the depicted L-tromino pieces into the grid.


• Pieces can be rotated or reflected.


• Pieces cannot be adjacent to another piece, but they may touch at a corner.


• Empty cells are all connected.


• Cells marked with a black circle must be part of a piece.


• Cells marked with a white circle must be empty.

Across
1. Sauce for diplomatic leaders (3)

3. Sun god with head of Merino sheep (3)
6. See scales turning nonstop (9)
7. Return of divine being Anubis, depicted with one's head (3)
9. Go change the direction of Fourth Street (4)
12. I think I am nothing (3)
13. President is out after prisoners (4)
15. The one and only part of the human body (4)
16. Honorific held by Osiris (3)

Down
1. Pass judgment for Seth's crime: No "eye for eye" (6)

2. Ptah at odds with Asarte's last seed (3)
3. Hungry elephant sampling cereal (3)
4. Israeli intelligence contracted to plant in 14 down (4)
5. Half of judgment is getting reversed? No comments (8)
8. Graphical user interface design: Starters handbook (5)
10. Helicopter part going up and down (5)
11. The twisted letter with stroke (3)
14. Mostly fictitious wetland (3)

_{¹ Paraphrased from the original rules on Melon's Puzzles.}

Solve both puzzles to answer the question: What do computers need?

Answer

Computers need

PROCESSING UNITS

as we can see:

Explanations of clues:

1a. DIP(-lomatic). 3a. RA+M(-erino). 6a. SEESCALES*. 7a. GOD<. 9a. Triple def (third is a poker reference). 12a. IM+O; abbr. 13a. substring. 15a. double def. 16. substring.
1d. DE(-i)CIDE. (I confess I don't know what Seth is meant here.) 2d. P(-t)A(-h) containing (-astart)E. 3d. substring. 4d. MOSS(-ad). 5d. (-judg)MENT + IS containing NO<. 8d. GUI+DE(-sign). 10d. ROTOR is a palindrome. 11d. THE*. 14d. BOG(-us).

(Of course I didn't look at NudgeNudge's answers, posted while I was completing this.)

Credit where due: Thanks to Alconja for figuring out the third part of the triple definition in 9a.