Checkpoint on Readonly db

1) Are there checkpoints issued on Readonly database as there's no modification done?

2) Internal Sql 2008 book

....." most writing to disk doesn’t actually happen during checkpoint operations. Checkpoints are just a way to guarantee that all dirty pagesnot written by othermechanisms are still written to the disk in a timely manner."

Here i think LAZY Writer she's referring in memory pressure case to, but is there any other process also which writes to Disk other than CHECKPOINT, LZYwrtr process?

Manish