Changes between Version 8 and Version 9 of Requirements

Timestamp:

Aug 2, 2012, 8:36:03 PM (12 years ago)

Author:

David Azarewicz

Comment:

--

Requirements

@@ -46 +46 @@
  2. Some SCSI drivers cannot handle the interrupt being changed from what the BIOS has set it to, regardless of whether or not it is greater than 15.
 Both of these problems can be handled by using the /VW switch.
+
+== Hyperthreading ==
+Hyperthreading is not recommended.
+
+The PSD does not know or care about hyperthreading. Therefore there is no issue about the PSD supporting or not supporting hyperthreading. It just doesn't care. The only reason people think that the PSD has anything at all to do with hyperthreading is because hyperthreading, by definition, involves multiple CPUs, and you cannot use multiple CPUs without a PSD.
+
+The OS/2 kernel is another matter.  The scheduler in the OS/2 kernel assumes symmetrical CPUs. After all, that is what the S in SMP means. The fake CPUs created by hyperthreading are most definitely not symmetrical.  This will negatively affect performance.
+
+There are also other differences with the fake CPUs that can negatively affect system stability.  If you use hyperthreading you may experience the following symptoms. Your results may vary depending on the specific hardware implementation in your system.
+- Slow performance
+- System stability issues
+- Strange CPU usage
+- Failure to boot
+- Random system hangs, or failures.
+
+For these reasons we cannot provide support for systems that use hyperthreading.
 
 == Power Off ==