On 7 Dec 2024, at 14:45, Henry Bent <henry.r.bent@gmail.com> wrote:
> Interesting, thank you for the explanation. How was file locking handled for DOS programs? Did it have some sort of internal call to "share" or was there a more elegant method?
Well, as the Unix filesystem was connected to MS-DOS as a “network drive” it had rudimentary opportunistic locking via the SMB protocol which I am not entirely sure actually translated to anything on the Unix side. There was often data corruption when writing from multiple MS-DOS sessions to the same file so the customer, who was particularly keen on the reading from multiple terminals more than the writing, simply decided that only one person could write into the inventory at one time. “Sneaker lock”?
Sadly, that's the answer I was expecting - the locking didn't really work in practice. That might go some way towards explaining why this concept of multiple DOS sessions under UNIX didn't really have widespread adoption.
There were always all sorts of "DOS under UNIX" ideas, from these early concepts through all the way to Sun's physical PC boards, but none of them ever really seemed to gain significant traction. The only connecting concept seems to be that DOS just wasn't meant to be a multi-user OS, and certainly not a networked one.
-Henry