<p><pre><code>  Constantly crashing and needing reboot
</code></pre>
Not at all, in my experience.  They were <i>vulnerable</i> to power dips but otherwise low trouble (by the standards of the time; not like, say, SunOS on Sparc).  They would go weeks or months without a reboot (such had to be scheduled through upper management and customers).<p>IBMs even had a cool <i>Quiesce</i> feature where you could stop the processor (and all I&#x2F;O) while leaving the system stable.  This was necessary when doing things like disconneting&#x2F;reconnecting peripherals and drives.  But it didn&#x27;t sing &quot;Daisy, Daisy&quot; in the process.