One of the issues that I have run up against running OPENVMS on simh is that the tuning parameters for the OS are not optimal for todays high speed disks.
If you run a IO intensive application (like synching mirrored disks under VMS) the IO operations can easily chew up all of the emulated cycles available. I had given some thought to changing the disk drivers so that there were built-in delays to more accurately represent that dasd that was availble for the 3900 - but decided that it wasn't worth the effort... Villy ----- Original Message ----- From: Gary Lee Phillips <[email protected]> Date: Monday, May 17, 2010 10:09 Subject: Re: [Simh] Batch vs interactive To: [email protected] > The answer depends on what machine you are emulating and with what > operating system. Something like a VAX with OpenVMS has a lot of > tuning parameters within the operating system for balancing > batch and > foreground priorities. Most systems that had simultaneous batch and > interactive operation were set up in this way. But the controls are > internal to the operating system software, not to the hardware itself > and therefore not in the purview of SIMH settings. > > Or did you mean that you are letting something run on a SIMH emulation > and it gets in the way of doing other things on your host machine? > There is a setting to control the percentage of the host CPU > that is > used by most SIMH emulators I've tried, though I don't know > whether it > is active in all of them: > > SET THROTTLE xx% > > This command given at the SIMH command prompt limits the amount > of CPU > that can be taken up by the SIMH emulation at any time to xx% of the > whole. > > It will not, however, balance between batch and interactive processes > running within the emulation. Those will both be slowed down by an > equal amount. Tuning that balance requires internal settings in the > emulated environment. > > --Gary > _______________________________________________ > Simh mailing list > [email protected] > http://mailman.trailing-edge.com/mailman/listinfo/simh >
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