EDIT1:
After I run the reinstaller, I get this output:
iMac:~ dennis$ diskutil list/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *256.1 GB disk0
1: EFI 209.7 MB disk0s1
2: Apple_HFS Crucial M4 SSD 255.2 GB disk0s2
3: Apple_Boot Recovery HD 650.0 MB disk0s3
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *1.0 TB disk1
1: EFI 209.7 MB disk1s1
2: Apple_CoreStorage 999.9 GB disk1s2
3: Apple_Boot Boot OS X 134.2 MB disk1s3
/dev/disk3
#: TYPE NAME SIZE IDENTIFIER
0: Apple_HFS Storage *999.7 GB disk3
What is the EFI and Apple_Boot on /dev/disk1?