Based solely on the article, it appears to be Oracle's Systems division which seems to own SPARC and Solaris - not sure what else without googling.
Re:Update on Oracle Layoffs
by lemoncucumber on Monday December 19, 2016 @02:28AM
(#13210011)
Sounds like it's just talking about the OS/hardware group(s) that Oracle acquired back when they bought Sun.
Is this 50% of Oracle, that's being speculated, or just some specific division within Oracle? 50% of Oracle, does seem very high.