🚀 go-pugleaf

I don't use Windows myself, but I was just musing about how it gets the
multiple DOS sessions to work in 386 enhanced mode.

Now, I can understand how to run multiple copies of MSDOS each in
their own virtual 386 machine and even how to keep basic disk IO sane.
However, I can't figure out why the different instances of DOS don't
step on each other's toes as far as the filesystem is concerned.

For example, take 2 processes writing to a file "simultaneously". They
both come along and find out what blocks are free and let's assume
that the information stays withing the DOS buffers so they don't need
to go back to disk again. What stops both processes trying to use the
same "free" blocks?

Of course, you could apply the same question to any disk structure,
for example two processes trying to create files in the same
directory.

Anyone got any ideas on how it works?

Ken
-- 
- Ken Reed, Joint European Torus, Abingdon, Oxfordshire, UK
  kr@jet.uk
- Disclaimer: Please note that the above is a personal view and should not 
  be construed as an official comment from the JET project.