R/W OPTICAL(4,F) AIX Technical Reference R/W OPTICAL(4,F) ------------------------------------------------------------------------------- r/w optical PURPOSE Supports the r/w optical device driver. DESCRIPTION The r/w optical device driver provides block and character access to the r/w optical disks. The r/w optical special files are unique to AIX PS/2. The minor number of this system device is determined via the special files /dev/rwoptn and /dev/rrwoptn, where n specifies the minor number. In raw I/O, the buffer must begin on a 512 byte boundary and counts must be a multiple of 512 bytes. lseek system calls also must specify a multiple of 512 bytes. However, for the most efficient raw I/O, the buffer should be on a 4096 byte boundary and counts should be a multiple of 4096 (the page size). IOCTL OPERATIONS The IOCTYPE type ioctl call returns the value DD_RWOPT, defined in . The IOCINFO type ioctl call returns the structure defined in . All of the below mentioned ioctl types are mentioned in the file. The SCSIINFO and the SCSIGDT type ioctl calls are for obtaining the SCSI configuration information. The SCSIINFO type ioctl provides the mapping between the device number and the device triple i.e. the Card number, the Logical Unit Number and the Physical Unit Number. The SCSIGDT type ioctl provides the information about the on-disk configuration table. The HDIORST type ioctl provides a means of resetting the device. The SCSIHDFMT type ioctl provides a means to format the optical disk cartridge. FILES /dev/rwopt0, /dev/rwopt1, ... /dev/rrwopt0, /dev/rrwopt1, ... RELATED INFORMATION In this book: "format" and "ioctlx, ioctl." Processed October 21, 1991 R/W OPTICAL(4,F) 1