READER(4,F) AIX Technical Reference READER(4,F) ------------------------------------------------------------------------------- reader PURPOSE Supports the IBM virtual card reader driver. SYNOPSIS # include # include DESCRIPTION Note: The reader device driver can only accept 80-character records. While punch cards are obsolete in a UNIX environment, some VM software provides extensive file transfer and communication facilities using the concept of "virtual cards". To interface to this mechanism, AIX/370 provides a driver for a virtual card reader device. The special files used to read from the card reader are of the form /dev/rdr#, where # is the device unit number. They are unique to AIX/370. The card reader can only be opened for reading. When read, the virtual deck in the reader is read, one record per read, up to the maximum size of the buffer specified. If the device is closed before all of the cards have been read, the remaining cards are flushed. No IOCTL operations are available besides the standard IOCTYPE and IOCINFO commands. ERROR CONDITIONS In addition to the errors listed in "ioctlx, ioctl, gtty, stty," "open, openx, creat," and "read, readv, readx," system calls to this device can fail in the following circumstances: ENXIO Attempt to write to the reader. ENXIO The reader is not currently closed. EIO The I/O from the reader failed during the operation. RELATED INFORMATION In this book: "ioctlx, ioctl, gtty, stty," "open, openx, creat," and "read, readv, readx." Processed April 9, 1991 READER(4,F) 1