>Is there ever a "need" to write an SVC?

There are few reasons that come to mind, and none that
are likely truly needed outside of the operating system.

>Or to put it another way, is there sometimes a need to get
>OS services from a problem state program like in an SVC?

Yes

>And if so, are PC routines the new way?

If by "new" you mean "for 30+ years", yes
(25 years or so if you want a stacking PC).

>Were once SVC's ok, and now they are not preferred?

PC did not used to exist initially. SVC was the only choice at that time.

Peter Relson
z/OS Core Technology Design

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