Across

1 Ubiquitous pointer from Mickey (5)
4 Conflagration goes up against bricks to protect computer user (8)
9 See 21 down
10 One piece of winter sports equipment, speaking drunkenly, represents characters (5)
11 Military physics detected in Find My iPhone icon (5)
13 No-strings alternative for digital communications acronym (4)
14 Offline activities can be found in their laptop (1,1,1)
16 Escape drive with Bond car feature (5)
18 Malicious online coder wears dark headgear (8)
21 Files that need interpreting found around barycentres (8)
22 Telephone replacement is in the sky, perhaps? (5)
25 Vital computer circuitry made from bits of carbon and plutonium (1,1,1)
26 Bid website created when bishop leaves rebuilt abbey (4)
29 Chatting with the face seen in supremo jingoism (5)
30 Install video player to accompany army (5)
31 Rock formation has anonymity in store (3)
32 Excited, anxious feeling when streaming online thriller (8)
33 Short software exhibitions, e.g. shareware, freemium services or beta versions (5)

Down

1 Damaging download puts conflict into gender (7)
2 Twisted ruse is beneath the system administrator (4)
3 Digital communication has scrambled Amile (5)
5 First things, making up WWW, HTML and URL (8)
6 Peripheral devices assembled from aural parts (9)
7 Byte, nibble, bit – the first, relatively (7)
8 Muddled coins all over your desktop (5)
12 Learner quits US computer manufacturer to go back on his words (3)
15 Could Web have originated within nicer neighbourhood? (4)
17 A precious shade in the bad magic phrase: 40E0D0 (9)
19 Informal greeting: 01101000, 01101001, 01111001, 01100001 (4)
20 Online community devotees heard to acquire assents with meditative state (8)
21 and 9 across Notable NeXT machine user hears fiery rocket stages on downwind slope (7-3)
23 Increasingly professional online diversions that French art harbours (7)
24 Internet award like mallard toes (5)
25 A big cheese like Cook, Dorsey or Zuckerberg (1,1,1)
27 Did basic maths to get connected in online network (5)
28 Something in your online shopping cart? It’s reorder time! (4)

Download the crossword as a PDF here. Answers will be published in the May issue of Physics World. Please note that this crossword is just for fun; there are no prizes.