Genome linear in phage, circular in host. Lysogenic - early genes transcribed and translated. Repressor appears and binds to the two operators which shuts down transcription of all phage genes except for repressor itself. No progeny produced.
Phage integrates into host genome and becomes prophage.
Not disadvantageous for host. Immediate Early cro product is Cro, an antirepressor that turns off cI , the repressor gene. Important in lytic and lysogenic cycles. Head, tail and lysis proteins produced by late genes. P RM used during lysogeny to ensure plenty of repressor.