mdj <mdj.mdj@gmail.com> wrote:
The biggest performance problem with the Pascal system was character
device IO, since such a request went through the p-code based OS to a
pluggable device mapper, and then onto the actual device driver.
Replacing the console driver with a direct-to-80 column card driver in
assembly made massive performance differences.
You just reminded me of how annoying the Orca shell was for me to deal with
when writing HardPressed. GS/OS came with a fancy new console driver,
and Orca used it. Which was great, except that the shell commands wrote
one character at a time.
Since HardPressed intercepts all GS/OS calls, the overhead added to figure
out if something was accessing a HardPressed-managed file was added to
every character output by the Orca shell. I jumped through some hoops
to optimize it, but there's only so much you can do.
The net result was that the APW shell was noticeably faster for things
like getting directory listings, and was even more noticeably faster when
HardPressed was enabled.