Of course, his method of preparing to move offices (a common occurrence at IBM) was to
1. Take his (RS-6000) workstation home with him the night of the move.
2. Otherwise, just lock his desk.
He didn't have anything in his office but his chair, desk, and workstation.
Sync is not synchronous. When it is back to the shell there is no guarantee that data in memory is fully copied to disk.
However, it sets a flag that is reset when the copying is done. Sync will hang if the flag is set.
So the first sync arms the copy and sets the flag and is back to the shell.
The second sync starts, blocks at the flag. The flag gets reset and it is back to the shell.
So the 2nd sync going back to the shell is a guarantee that the first sync is fine and data is safe
Of course, his method of preparing to move offices (a common occurrence at IBM) was to
1. Take his (RS-6000) workstation home with him the night of the move.
2. Otherwise, just lock his desk.
He didn't have anything in his office but his chair, desk, and workstation.