3 May
2016
3 May
'16
12:10 p.m.
On May 3, 2016, at 2:18 PM, Erik Baigar <erik at
baigar.de> wrote:
On Tue, 3 May 2016, Paul Koning wrote:
It's quite a nice system. The internals are fairly extensively documented in
Dijkstra's early "EWD" documents (at the U Texas Austin archive), though a
fair fraction are in Dutch. Among other interesting aspects is spooling to virtual memory
for both input (paper tape) and output (printer, paper tape punch, plotter). And of
course the impressive design discipline documented in his famous paper "The
structure of the THE operating system".
For that matter, the machine is interesting. Not only is this the place where semaphores
were invented and first applied, but they aren't just a software concurrency control
mechanism. The I/O system uses semaphores, too -- one that counts pending I/O requests,
and another that counts completions and ties to the interrupt request.
paul
further, at least as far as the THE operating
system in 1964, on the EL-X8. That OS is particularly interesting because it has virtual
memory and demand paging without any hardware help, without address mapping or protection.
Wow - and this machine still used a drum for secondary
storage; quite outstanding, you are right!