[Info-vax] Disable hyper-threading from the DCL prompt

[Stephen Hoffman]

On 2015-03-04 19:34:53 +0000, RGB said:

> We have several x2800 i2's running VMS v8.4 and I seem to recall a 
> command, issued from the DCL prompt, which disables hyper-threading at 
> the CPU's.  I know there is another way to do so from EFI but I thought 
> it was also possible to do so from DCL.  (Knowing that it will not take 
> effect until the next reboot.)
> 
> Can someone please refresh my feeble mind as to the command?

Beyond that htread.exe tool, the SET CPU /NOCOTHREAD command is also 
available per 
<https://view.officeapps.live.com/op/view.aspx?src=http%3A%2F%2Fde.openvms.org%2FTUD2008%2FHyperthread_Support_in_OpenVMS_V8.ppt>, 
though it does not appear that this DCL command was documented in the 
help libraries — more fodder for VSI to ponder.

The command is honored on an OpenVMS V8.4 test server, without errors.  
Whether it works as intended, I did not check — the test server does 
not support hyperthreads.

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