| Index | NAME | Function |
|---|---|---|
| D.4.1 | INCORE | File location (disk or memory) |
| D.4.2 | IEXIST | Use existing file |
| D.4.3 | IFKEEP | Keep files |
| D.4.4 | IREST | Write restart information |
| D.4.5 | IOLAST | Write to end of file on open |
| D.4.6 | IOKIDS | Open for access by children |
| D.4.7 | NUMIOQ | Number of I/O queues |
| D.4.8 | NUMSTP | Number of stripes per queue |
| D.4.9 | NUMVOL | Number of volumes per stripe |
| D.4.10 | MBYTES | Number of megabytes per volume |
| D.4.11 | IOTYPE | Perform raw or direct I/O |
| D.4.12 | IOMASK | Bind FMSDISK thread to CPU cores |
| D.4.13 | IOWARN | Special I/O warning options |
| D.4.14 | IOSYNC | Perform synchronous I/O |
| D.4.15 | LSECTR | Disk sector length (8-byte words) |
| D.4.16 | NOOPEN | Do not physically open files |
| D.4.17 | LBUFSI | Buffer size for submatrix integer records |
| D.4.18 | LBUFSR | Buffer size for submatrix real records |
| D.4.19 | LBUFSV | Buffer size for submatrix vector records |
| D.4.20 | FREEDU | Free disk space |