SCSI Device Command Operation ------------------- --------- hd_scsicmd issue a scsi-direct command to a scsi unit. Trackdisk Device Commands Supported by the SCSI Device ------------------------------------------------------ td_changestate return the disk present/not-present status of a drive. td_format initialize one or more tracks with a data buffer. td_protstatus return the write-protect status of a disk. td_seek move the head to a specific track. Exec Commands Supported by SCSI Device -------------------------------------- CMD_READ Read one or more sectors from a disk. CMD_START Restart a SCSI unit that was previously stopped with CMD_STOP. CMD_STOP Stop a SCSI unit. CMD_WRITE Write one or more sectors to a disk. Exec Functions as Used in This Chapter -------------------------------------- abortio() abort an i/o request to the scsi device. allocmem() allocate a block of memory. allocsignal() allocate a signal bit. checkio() return the status of an i/o request. closedevice() relinquish use of the scsi device. all requests must be complete before closing. doio() initiate a command and wait for completion (synchronous request). freemem() free a block of previously allocated memory. freesignal() free a previously allocated signal. opendevice() obtain use of the scsi device. you specify the type of unit and its characteristics in the call to OpenDevice(). waitio() wait for completion of an i/o request and remove it from the reply port. Exec Support Functions as Used in This Chapter ---------------------------------------------- createextio() create an extended iorequest structure for use in communicating with the SCSI device. createport() create a message port for reply messages from the SCSI device. Exec will signal a task when a message arrives at the port. deleteextio() delete the extended iorequest structure created by createextio(). deleteport() delete the message port created by createport().