Post B0qfkbFSEuosftZS3U by rose@snac.pinkro.se
(DIR) More posts by rose@snac.pinkro.se
(DIR) Post #B0qeWussKyr1Z8vARs by phreakmonkey@infosec.exchange
2025-11-07T22:04:18Z
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I'm "still run sync 3 times before removing an unmounted drive" years old.
(DIR) Post #B0qfkbFSEuosftZS3U by rose@snac.pinkro.se
2025-12-02T20:05:40Z
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My dad taught me to run sync, every time I want to unmount somethingwhy do it three times though? I was always told just once is fine
(DIR) Post #B0qg2WOP2178pNImkS by phreakmonkey@infosec.exchange
2025-12-02T20:07:10Z
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@rose paranoia, mostly. "sync" typically blocks on the cache writes being complete. So the second one is to verify that the first one completed, which is indicated by it returning immediately.The third one is basically saying "AND STAY DOWN" to the OS. 😆
(DIR) Post #B0qg6TrcNL3g8vr4ng by rose@snac.pinkro.se
2025-12-02T20:09:42Z
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Okay yeah that makes sense, i thought there was some historic thing about old storage types lol
(DIR) Post #B0qq8YvlVUOtyjQUU4 by frangdlt@mstdn.social
2025-12-02T21:53:27Z
1 likes, 0 repeats
@rose @phreakmonkey I believe this comes from the PDP11 timeframe. See screenshot:
(DIR) Post #B0tixBUQCfLdt48yNU by cks@mastodon.social
2025-12-04T01:37:39Z
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@phreakmonkey @rose In the very old days (like the late 1970s, with Research Unix V7) I believe that 'sync' didn't wait for things to be written out. So (AFAIK) the idea was that you had to type 'sync' and then wait long enough, but the simple thing was to tell people to type sync three times. On slow serial terminals, by the time you'd typed in the third sync the buffers probably were all written to disk.(Then this mutated to 'sync; sync; sync', which isn't really doing the job, and etc.)