Alternate updated versions of the excellent diagram at https://transactional.blog/how-to-learn/disk-io
m17e.co
mental-model-719c49df_santized.svg
1<?xml version="1.0" encoding="UTF-8"?>
2<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="642px" height="492px" viewBox="-0.5 -0.5 642 492">
3 <style type="text/css">
4 text { font-family: 'Berkeley Mono'; font-size: 12px; }
5 </style>
6 <defs></defs>
7 <g>
8 <g>
9 <g>
10 <g>
11 <g>
12 <rect x="160" y="0" width="120" height="30" fill="none" stroke="none"></rect>
13 </g>
14 <g>
15 <g transform="translate(-0.5 -0.5)">
16 <switch>
17 <text x="220" y="19" fill="rgb(0, 0, 0)" text-anchor="middle">Application Memory</text>
18 </switch>
19 </g>
20 </g>
21 </g>
22 <g>
23 <g>
24 <rect x="280" y="0" width="120" height="30" fill="none" stroke="none"></rect>
25 </g>
26 <g>
27 <g transform="translate(-0.5 -0.5)">
28 <switch>
29 <text x="340" y="19" fill="rgb(0, 0, 0)" text-anchor="middle">Page Cache</text>
30 </switch>
31 </g>
32 </g>
33 </g>
34 <g>
35 <g>
36 <rect x="400" y="0" width="120" height="30" fill="none" stroke="none"></rect>
37 </g>
38 <g>
39 <g transform="translate(-0.5 -0.5)">
40 <switch>
41 <text x="460" y="19" fill="rgb(0, 0, 0)" text-anchor="middle">Disk Cache</text>
42 </switch>
43 </g>
44 </g>
45 </g>
46 <g>
47 <g>
48 <rect x="520" y="0" width="120" height="30" fill="none" stroke="none"></rect>
49 </g>
50 <g>
51 <g transform="translate(-0.5 -0.5)">
52 <switch>
53 <text x="580" y="19" fill="rgb(0, 0, 0)" text-anchor="middle">Disk Storage</text>
54 </switch>
55 </g>
56 </g>
57 </g>
58 <g>
59 <g>
60 <rect x="20" y="60" width="100" height="20" fill="none" stroke="none"></rect>
61 </g>
62 <g>
63 <g transform="translate(-0.5 -0.5)">
64 <switch>
65 <text x="22" y="74" fill="rgb(0, 0, 0)">write()</text>
66 </switch>
67 </g>
68 </g>
69 </g>
70 <g>
71 <g>
72 <rect x="20" y="80" width="100" height="20" fill="none" stroke="none"></rect>
73 </g>
74 <g>
75 <g transform="translate(-0.5 -0.5)">
76 <switch>
77 <text x="22" y="94" fill="rgb(0, 0, 0)">O_DIRECT</text>
78 </switch>
79 </g>
80 </g>
81 </g>
82 <g>
83 <g>
84 <rect x="20" y="100" width="100" height="20" fill="none" stroke="none"></rect>
85 </g>
86 <g>
87 <g transform="translate(-0.5 -0.5)">
88 <switch>
89 <text x="22" y="114" fill="rgb(0, 0, 0)">+ O_SYNC</text>
90 </switch>
91 </g>
92 </g>
93 </g>
94 <g>
95 <g>
96 <rect x="20" y="180" width="140" height="20" fill="none" stroke="none"></rect>
97 </g>
98 <g>
99 <g transform="translate(-0.5 -0.5)">
100 <switch>
101 <text x="22" y="194" fill="rgb(0, 0, 0)">O_DIRECT + O_DSYNC</text>
102 </switch>
103 </g>
104 </g>
105 </g>
106 <g>
107 <g>
108 <rect x="20" y="120" width="100" height="20" fill="none" stroke="none"></rect>
109 </g>
110 <g>
111 <g transform="translate(-0.5 -0.5)">
112 <switch>
113 <text x="22" y="134" fill="rgb(0, 0, 0)">fsync()</text>
114 </switch>
115 </g>
116 </g>
117 </g>
118 <g>
119 <g>
120 <path d="M 333.63 70 L 223 70" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
121 <path d="M 338.88 70 L 331.88 73.5 L 333.63 70 L 331.88 66.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
122 <ellipse cx="220" cy="70" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
123 </g>
124 </g>
125 <g>
126 <g>
127 <path d="M 280 89.5 L 223 89.98" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
128 <ellipse cx="220" cy="90" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
129 </g>
130 </g>
131 <g>
132 <g>
133 <path d="M 280 90 L 400 90" fill="none" stroke="rgb(0, 0, 0)" stroke-width="2" stroke-miterlimit="10" stroke-dasharray="2 6"></path>
134 </g>
135 </g>
136 <g>
137 <g>
138 <path d="M 453.63 89.55 L 400 90" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
139 <path d="M 458.88 89.51 L 451.91 93.07 L 453.63 89.55 L 451.85 86.07 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
140 </g>
141 </g>
142 <g>
143 <g>
144 <path d="M 280 109.5 L 223 109.98" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
145 <ellipse cx="220" cy="110" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
146 </g>
147 </g>
148 <g>
149 <g>
150 <path d="M 280 110 L 400 110" fill="none" stroke="rgb(0, 0, 0)" stroke-width="2" stroke-miterlimit="10" stroke-dasharray="2 6"></path>
151 </g>
152 </g>
153 <g>
154 <g>
155 <path d="M 573.63 110 L 400 110" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
156 <path d="M 578.88 110 L 571.88 113.5 L 573.63 110 L 571.88 106.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
157 </g>
158 </g>
159 <g>
160 <g>
161 <path d="M 573.63 130 L 343 130" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
162 <path d="M 578.88 130 L 571.88 133.5 L 573.63 130 L 571.88 126.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
163 <ellipse cx="340" cy="130" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
164 </g>
165 </g>
166 <g>
167 <g>
168 <rect x="0" y="160" width="120" height="20" fill="none" stroke="none"></rect>
169 </g>
170 <g>
171 <g transform="translate(-0.5 -0.5)">
172 <switch>
173 <text x="2" y="174" fill="rgb(0, 0, 0)">Data Integrity</text>
174 </switch>
175 </g>
176 </g>
177 </g>
178 <g>
179 <g>
180 <rect x="0" y="40" width="120" height="20" fill="none" stroke="none"></rect>
181 </g>
182 <g>
183 <g transform="translate(-0.5 -0.5)">
184 <switch>
185 <text x="2" y="54" fill="rgb(0, 0, 0)">File Integrity</text>
186 </switch>
187 </g>
188 </g>
189 </g>
190 <g>
191 <g>
192 <rect x="20" y="200" width="100" height="20" fill="none" stroke="none"></rect>
193 </g>
194 <g>
195 <g transform="translate(-0.5 -0.5)">
196 <switch>
197 <text x="22" y="214" fill="rgb(0, 0, 0)">fdatasync()</text>
198 </switch>
199 </g>
200 </g>
201 </g>
202 <g>
203 <g>
204 <path d="M 573.63 210 L 343 210" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
205 <path d="M 578.88 210 L 571.88 213.5 L 573.63 210 L 571.88 206.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
206 <ellipse cx="340" cy="210" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
207 </g>
208 </g>
209 <g>
210 <g>
211 <path d="M 280 189.5 L 223 189.98" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
212 <ellipse cx="220" cy="190" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
213 </g>
214 </g>
215 <g>
216 <g>
217 <path d="M 280 190 L 400 190" fill="none" stroke="rgb(0, 0, 0)" stroke-width="2" stroke-miterlimit="10" stroke-dasharray="2 6"></path>
218 </g>
219 </g>
220 <g>
221 <g>
222 <path d="M 573.63 190 L 400 190" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
223 <path d="M 578.88 190 L 571.88 193.5 L 573.63 190 L 571.88 186.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
224 </g>
225 </g>
226 <g>
227 <g>
228 <rect x="20" y="300" width="130" height="20" fill="none" stroke="none"></rect>
229 </g>
230 <g>
231 <g transform="translate(-0.5 -0.5)">
232 <switch>
233 <text x="22" y="314" fill="rgb(0, 0, 0)">fsync()</text>
234 </switch>
235 </g>
236 </g>
237 </g>
238 <g>
239 <g>
240 <rect x="0" y="280" width="120" height="20" fill="none" stroke="none"></rect>
241 </g>
242 <g>
243 <g transform="translate(-0.5 -0.5)">
244 <switch>
245 <text x="2" y="294" fill="rgb(0, 0, 0)">macOS Only</text>
246 </switch>
247 </g>
248 </g>
249 </g>
250 <g>
251 <g>
252 <rect x="20" y="320" width="100" height="20" fill="none" stroke="none"></rect>
253 </g>
254 <g>
255 <g transform="translate(-0.5 -0.5)">
256 <switch>
257 <text x="22" y="334" fill="rgb(0, 0, 0)">fcntl(F_FULLSYNC)</text>
258 </switch>
259 </g>
260 </g>
261 </g>
262 <g>
263 <g>
264 <rect x="20" y="360" width="150" height="20" fill="none" stroke="none"></rect>
265 </g>
266 <g>
267 <g transform="translate(-0.5 -0.5)">
268 <switch>
269 <text x="22" y="374" fill="rgb(0, 0, 0)">F_NOCACHE + O_DSYNC</text>
270 </switch>
271 </g>
272 </g>
273 </g>
274 <g>
275 <g>
276 <path d="M 573.63 330 L 343 330" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
277 <path d="M 578.88 330 L 571.88 333.5 L 573.63 330 L 571.88 326.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
278 <ellipse cx="340" cy="330" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
279 </g>
280 </g>
281 <g>
282 <g>
283 <path d="M 280 369.5 L 223 369.98" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
284 <ellipse cx="220" cy="370" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
285 </g>
286 </g>
287 <g>
288 <g>
289 <path d="M 280 370 L 400 370" fill="none" stroke="rgb(0, 0, 0)" stroke-width="2" stroke-miterlimit="10" stroke-dasharray="2 6"></path>
290 </g>
291 </g>
292 <g>
293 <g>
294 <path d="M 453.63 370 L 400 370" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
295 <path d="M 458.88 370 L 451.88 373.5 L 453.63 370 L 451.88 366.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
296 </g>
297 </g>
298 <g>
299 <g>
300 <path d="M 453.63 309.97 L 343 309.51" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
301 <path d="M 458.88 310 L 451.87 313.47 L 453.63 309.97 L 451.9 306.47 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
302 <ellipse cx="340" cy="309.5" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
303 </g>
304 </g>
305 <g>
306 <g>
307 <rect x="20" y="220" width="140" height="20" fill="none" stroke="none"></rect>
308 </g>
309 <g>
310 <g transform="translate(-0.5 -0.5)">
311 <switch>
312 <text x="22" y="234" fill="rgb(0, 0, 0)">sync_file_range (btrfs,zfs)</text>
313 </switch>
314 </g>
315 </g>
316 </g>
317 <g>
318 <g>
319 <rect x="20" y="240" width="140" height="20" fill="none" stroke="none"></rect>
320 </g>
321 <g>
322 <g transform="translate(-0.5 -0.5)">
323 <switch>
324 <text x="22" y="254" fill="rgb(0, 0, 0)">sync_file_range (ext4,xfs)</text>
325 </switch>
326 </g>
327 </g>
328 </g>
329 <g>
330 <g>
331 <path d="M 453.63 230 L 343 230" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
332 <path d="M 458.88 230 L 451.88 233.5 L 453.63 230 L 451.88 226.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
333 <ellipse cx="340" cy="230" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
334 </g>
335 </g>
336 <g>
337 <g>
338 <path d="M 573.63 250 L 343 250" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
339 <path d="M 578.88 250 L 571.88 253.5 L 573.63 250 L 571.88 246.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
340 <ellipse cx="340" cy="250" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
341 </g>
342 </g>
343 <g>
344 <g>
345 <rect x="0" y="400" width="120" height="20" fill="none" stroke="none"></rect>
346 </g>
347 <g>
348 <g transform="translate(-0.5 -0.5)">
349 <switch>
350 <text x="2" y="414" fill="rgb(0, 0, 0)">Windows Only</text>
351 </switch>
352 </g>
353 </g>
354 </g>
355 <g>
356 <g>
357 <rect x="20" y="420" width="130" height="20" fill="none" stroke="none"></rect>
358 </g>
359 <g>
360 <g transform="translate(-0.5 -0.5)">
361 <switch>
362 <text x="22" y="434" fill="rgb(0, 0, 0)">NO_BUFFERING</text>
363 </switch>
364 </g>
365 </g>
366 </g>
367 <g>
368 <g>
369 <path d="M 280 429.5 L 223 429.98" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
370 <ellipse cx="220" cy="430" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
371 </g>
372 </g>
373 <g>
374 <g>
375 <path d="M 280 430 L 400 430" fill="none" stroke="rgb(0, 0, 0)" stroke-width="2" stroke-miterlimit="10" stroke-dasharray="2 6"></path>
376 </g>
377 </g>
378 <g>
379 <g>
380 <path d="M 453.63 430 L 400 430" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
381 <path d="M 458.88 430 L 451.88 433.5 L 453.63 430 L 451.88 426.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
382 </g>
383 </g>
384 <g>
385 <g>
386 <rect x="20" y="460" width="130" height="20" fill="none" stroke="none"></rect>
387 </g>
388 <g>
389 <g transform="translate(-0.5 -0.5)">
390 <switch>
391 <text x="22" y="474" fill="rgb(0, 0, 0)">FlushFileBuffers</text>
392 </switch>
393 </g>
394 </g>
395 </g>
396 <g>
397 <g>
398 <path d="M 572.63 470 L 342 470" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
399 <path d="M 577.88 470 L 570.88 473.5 L 572.63 470 L 570.88 466.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
400 <ellipse cx="339" cy="470" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
401 </g>
402 </g>
403 <g>
404 <g>
405 <path d="M 640 30 L 0 30" fill="none" stroke="#cccccc" stroke-miterlimit="10"></path>
406 </g>
407 </g>
408 <g>
409 <g>
410 <path d="M 640 150 L 0 150" fill="none" stroke="#cccccc" stroke-miterlimit="10"></path>
411 </g>
412 </g>
413 <g>
414 <g>
415 <path d="M 640 270 L 0 270" fill="none" stroke="#cccccc" stroke-miterlimit="10"></path>
416 </g>
417 </g>
418 <g>
419 <g>
420 <path d="M 640 390 L 0 390" fill="none" stroke="#cccccc" stroke-miterlimit="10"></path>
421 </g>
422 </g>
423 <g>
424 <g>
425 <path d="M 640 490 L 0 490" fill="none" stroke="#cccccc" stroke-miterlimit="10"></path>
426 </g>
427 </g>
428 <g>
429 <g>
430 <rect x="20" y="340" width="140" height="20" fill="none" stroke="none"></rect>
431 </g>
432 <g>
433 <g transform="translate(-0.5 -0.5)">
434 <switch>
435 <text x="22" y="354" fill="rgb(0, 0, 0)">F_NOCACHE + O_SYNC</text>
436 </switch>
437 </g>
438 </g>
439 </g>
440 <g>
441 <g>
442 <path d="M 280 349.5 L 223 349.98" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
443 <ellipse cx="220" cy="350" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
444 </g>
445 </g>
446 <g>
447 <g>
448 <path d="M 280 350 L 400 350" fill="none" stroke="rgb(0, 0, 0)" stroke-width="2" stroke-miterlimit="10" stroke-dasharray="2 6"></path>
449 </g>
450 </g>
451 <g>
452 <g>
453 <path d="M 453.63 350 L 400 350" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
454 <path d="M 458.88 350 L 451.88 353.5 L 453.63 350 L 451.88 346.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
455 </g>
456 </g>
457 <g>
458 <g>
459 <rect x="20" y="440" width="130" height="20" fill="none" stroke="none"></rect>
460 </g>
461 <g>
462 <g transform="translate(-0.5 -0.5)">
463 <switch>
464 <text x="22" y="454" fill="rgb(0, 0, 0)">+ WRITE_THROUGH</text>
465 </switch>
466 </g>
467 </g>
468 </g>
469 <g>
470 <g>
471 <path d="M 280 449.5 L 223 449.98" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
472 <ellipse cx="220" cy="450" rx="3" ry="3" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)"></ellipse>
473 </g>
474 </g>
475 <g>
476 <g>
477 <path d="M 280 450 L 400 450" fill="none" stroke="rgb(0, 0, 0)" stroke-width="2" stroke-miterlimit="10" stroke-dasharray="2 6"></path>
478 </g>
479 </g>
480 <g>
481 <g>
482 <path d="M 573.63 450 L 400 450" fill="none" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
483 <path d="M 578.88 450 L 571.88 453.5 L 573.63 450 L 571.88 446.5 Z" fill="rgb(0, 0, 0)" stroke="rgb(0, 0, 0)" stroke-miterlimit="10"></path>
484 </g>
485 </g>
486 </g>
487 </g>
488 </g>
489 <switch>
490 <g></g>
491 <a transform="translate(0,-5)" xlink:href="https://www.drawio.com/doc/faq/svg-export-text-problems">
492 <text text-anchor="middle" font-size="10px" x="50%" y="100%">Text is not SVG - cannot display</text>
493 </a>
494 </switch>
495</svg>