Currently there are six parameters, initially all unfrozen.
| XSPEC> freeze 2 | | Parameter 2 is frozen. |
| XSPEC> freeze 4-6 | | Parameters 4, 5, and 6 are frozen. |
| XSPEC> thaw 2 3-5 | | Parameters 2, 4, and 5 are thawed, parameter 3 is unaffected. |
| XSPEC> freeze | | Parameters 3,4,5 are frozen (the last range input by a freeze or thaw command). |