-struct iob iob[NFILES];
-
-extern int errno; /* just like unix */
-
-/* error codes */
-#define EBADF 1 /* bad file descriptor */
-#define EOFFSET 2 /* relative seek not supported */
-#define EDEV 3 /* improper device specification on open */
-#define ENXIO 4 /* unknown device specified */
-#define EUNIT 5 /* improper unit specification */
-#define ESRCH 6 /* directory search for file failed */
-#define EIO 7 /* generic error */
-#define ECMD 10 /* undefined driver command */
-#define EBSE 11 /* bad sector error */
-#define EWCK 12 /* write check error */
-#define EECC 13 /* uncorrectable ecc error */
-#define EHER 14 /* hard error */
-
-/* ioctl's -- for disks just now */
-#define SAIOHDR (('d'<<8)|1) /* next i/o includes header */
-#define SAIOCHECK (('d'<<8)|2) /* next i/o checks data */
-#define SAIOHCHECK (('d'<<8)|3) /* next i/o checks header & data */
-#define SAIONOBAD (('d'<<8)|4) /* inhibit bad sector forwarding */
-#define SAIODOBAD (('d'<<8)|5) /* enable bad sector forwarding */
-#define SAIOECCLIM (('d'<<8)|6) /* limit ecc correction to 5 bits */
-#define SAIOECCUNL (('d'<<8)|7) /* use standard ecc procedures */
-#define SAIODEVDATA (('d'<<8)|8) /* get device data */
-#define SAIOSSI (('d'<<8)|9) /* set skip sector inhibit */
-#define SAIONOSSI (('d'<<8)|10) /* inhibit skip sector handling */
-#define SAIOSSDEV (('d'<<8)|11) /* is device skip sector type? */
-#define SAIODEBUG (('d'<<8)|12) /* enable/disable debugging */
-#define SAIOSEVRE (('d'<<8)|13) /* severe burnin, no ECC, no retries */
-#define SAIONSEVRE (('d'<<8)|14) /* clear severe burnin */
-
-/* codes for sector header word 1 */
-#define HDR1_FMT22 0x1000 /* standard 16 bit format */
-#define HDR1_OKSCT 0xc000 /* sector ok */
-#define HDR1_SSF 0x2000 /* skip sector flag */