I/O feedback area

The results of I/O operations are communicated to the program using i5/OS messages and I/O feedback information. The I/O feedback area is updated for every I/O operation unless your program is using blocked record I/O. In that case, the feedback area is updated only when a block of records is written. Some of the information reflects the last record in the block. Other information, such as the count of I/O operations, reflects the number of operations on blocks of records and not the number of records. See your high-level language manual to determine if your program uses blocked record I/O.

The I/O feedback area consists of two parts: a common area and a file-dependent area. The file-dependent area varies by the file type. This topic discusses device file type of printers only.

Common I/O feedback area

Offset Data Type Length in Bytes Contents
0 Binary 2 Offset to file-dependent feedback area.
2 Binary 4 Write operation count. Updated only when a write operation completes successfully. For blocked record I/O operations, this count is the number of blocks, not the number of records.
6 Binary 4 Read operation count. Not applicable to printers.
10 Binary 4 Write-read operation count. Not applicable to printers.
14 Binary 4 Other operation count. Number of successful operations other than write, read, or write-read. Updated only when the operation completes successfully. This count includes force-end-of-data.
18 Character 1 Reserved.
19 Character 1 Current operation.
hex 05
Write or write block
hex 09
Force-end-of-data
20 Character 10 Name of the record format just processed, which is either:
  • Specified on the I/O request, or
  • Determined by default or format selection processing
30 Character 2 Device class:

Byte 1:

hex 00
Database
hex 01
Display
hex 02
Printer
hex 04
Diskette
hex 05
Tape
hex 09
Save
hex 0B
ICF

Byte 2 (if byte 1 is 02 for printer):

hex 02
5256 Printer
hex 0C
5224/5225 printers
hex 0F
5219 Printer
hex 10
5583 Printer (DBCS)
hex 11
5553 Printer (DBCS)
hex 14
3270 Printer
hex 21
4234 (SCS) Printer
hex 22
3812 (SCS) Printer
hex 23
4214 Printer
hex 24
4224 (IPDS™) Printer
hex 25
4245 Printer
hex 29
5262 Printer
hex 30
3812 (IPDS) Printer
hex 31
4234 (IPDS) Printer
hex 32
IPDS printer, model unspecified
hex 55
6252 (SCS) Printer
hex 57
4230 (IPDS) Printer
hex 63
3935 (IPDS) Printer
32 Character 10 Device name. The name of the device for which the operation just completed. The device name is supplied only for printer, display, tape, diskette, and ICF files. For printer files being spooled, the value is *N. For printer files not being spooled, the value is the device description name.
42 Binary 4 Not applicable to printer.
46 Character 80 Reserved.
126 Binary 2 Not applicable to printer.
128 Binary 2 For printers, the field value is the record format length, including first-character forms control, option indicators, source sequence numbers, and program-to-system data. If the value is zero, use the field at offset 42.
130 Character 2 Reserved.
132 Binary 4 Not applicable to printer.
136 Character 8 Reserved.

I/O feedback area for printer files

Offset Data Type Length in Bytes Contents
0 Binary 2 Current line number in a page.
2 Binary 4 Current page count.
6 Character 1 Miscellaneous flags
Bit 1:
Spooled file deleted.
Bit 2–8:
Reserved.
.
7 Character 27 Reserved.
34 Character 2 Major return code.
00
Operation completed successfully
80
Permanent system or file error
81
Permanent device error
82
Open operation failed
83
Recoverable device error occurred
36 Character 2 Minor return code.