Common I/O feedback area

 

This table shows the common I/O feedback area of the i5/OS^® operating system.

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Table 1. Common I/O feedback area

Offset	Data type	Length	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. Updated only when a read operation completes successfully. For blocked record I/O operations, this count is the number of blocks, not the number of records.
10	Binary	4	Write-read operation count. Updated only when a write-read operation completes successfully.
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 update, delete, force-end-of-data, force-end-of-volume, change-end-of-data, release record lock, and acquire/release device operations.
18	Character	1	Reserved.
19	Character	1	Current operation. hex 01 Read or read block or read from invited devices hex 02 Read direct hex 03 Read by key hex 05 Write or write block hex 06 Write-read hex 07 Update hex 08 Delete hex 09 Force-end-of-data hex 0A Force-end-of-volume hex 0D Release record lock hex 0E Change end-of-data hex 0F Put deleted record hex 11 Release device hex 12 Acquire device
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 For display files, the default name is either the name of the only record format in the file or the previous record format name for the record written to the display that contains input-capable fields. Because a display file might have multiple formats on the display at the same time, this format might not represent the format where the last cursor position was typed. For ICF files, the format name is determined by the system, based on the format selection option used. Refer to the ICF Programming book for more information.
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 contains hex 00): hex 00 Nonkeyed file hex 01 Keyed file Byte 2 (if byte 1 does not contain hex 00): hex 02 5256 Printer hex 07 5251 Display Station hex 08 Spooled hex 0A BSCEL hex 0B 5291 Display Station hex 0C 5224/5225 printers hex 0D 5292 Display Station hex 0E APPC hex 0F 5219 Printer hex 10 5583 Printer (DBCS) hex 11 5553 Printer hex 12 5555-B01 Display Station hex 13 3270 Display Station hex 14 3270 Printer hex 15 Graphic-capable device hex 16 Financial Display Station hex 17 3180 Display Station hex 18 Save file hex 19 3277 DHCF device
			hex 1A 9347 Tape Unit hex 1B 9348 Tape Unit hex 1C 9331-1 Diskette Unit hex 1D 9331-2 Diskette Unit hex 1E Intrasystem communications support hex 1F Asynchronous communications support hex 20 SNUF hex 21 4234 (SCS) Printer hex 22 3812 (SCS) Printer hex 23 4214 Printer hex 24 4224 (IPDS™) Printer hex 25 4245 Printer hex 26 3179-2 Display Station hex 27 3196-A Display Station hex 28 3196-B Display Station hex 29 5262 Printer hex 2A 6346 Tape Unit hex 2B 2440 Tape Unit hex 2C 9346 Tape Unit hex 2D 6331 Diskette Unit hex 2E 6332 Diskette Unit
			hex 30 3812 (IPDS) Printer hex 31 4234 (IPDS) Printer hex 32 IPDS printer, model unknown hex 33 3197-C1 Display Station hex 34 3197-C2 Display Station hex 35 3197-D1 Display Station hex 36 3197-D2 Display Station hex 37 3197-W1 Display Station hex 38 3197-W2 Display Station hex 39 5555-E01 Display Station hex 3A 3430 Tape Unit hex 3B 3422 Tape Unit hex 3C 3480 Tape Unit hex 3D 3490 Tape Unit hex 3E 3476-EA Display Station hex 3F 3477-FG Display Station hex 40 3278 DHCF device hex 41 3279 DHCF device hex 42 ICF finance device hex 43 Retail communications device hex 44 3477-FA Display Station
			hex 45 3477-FC Display Station hex 46 3477-FD Display Station hex 47 3477-FW Display Station hex 48 3477-FE Display Station hex 49 6367 Tape Unit hex 4A 6347 Tape Unit hex 4D Network Virtual Terminal Display Station hex 4E 6341 Tape Unit hex 4F 6342 Tape Unit hex 50 6133 Diskette Unit hex 51 5555-C01 Display Station hex 52 5555-F01 Display Station hex 53 6366 Tape Unit hex 54 7208 Tape Unit hex 55 6252 (SCS) Printer hex 56 3476-EC Display Station hex 57 4230 (IPDS) Printer hex 58 5555-G01 Display Station hex 59 5555-G02 Display Station hex 5A 6343 Tape Unit hex 5B 6348 Tape Unit hex 5C 6368 Tape Unit hex 5D 3486-BA Display Station hex 5F 3487-HA Display Station
			hex 60 3487-HG Display Station hex 61 3487-HW Display Station hex 62 3487-HC Display Station hex 63 3935 (IPDS) Printer hex 64 6344 Tape Unit hex 65 6349 Tape Unit hex 66 6369 Tape Unit hex 67 6380 Tape Unit hex 68 6378 Tape Unit hex 69 6390 Tape Unit hex 70 6379 Tape Unit hex 71 9331-11 Diskette Unit hex 72 9331-12 Diskette Unit hex 73 3570 Tape Unit hex 74 3590 Tape Unit hex 75 6335 Tape Unit
32	Character	10	Device name. The name of the device for which the operation just completed. Supplied only for display, printer, tape, diskette, and ICF files. For printer or diskette files being spooled, the value is *N. For ICF files, the value is the program device name. For other files, the value is the device description name.
42	Binary	4	Length of the record processed by the last I/O operation (supplied only for an ICF, display, tape, or database file). On ICF write operations, this is the record length of the data. On ICF read operations, it is the record length of the record associated with the last read operation.
46	Character	80	Reserved.
126	Binary	2	Number of records retrieved on a read request for blocked records or sent on a write or force-end-of-data or force-end-of-volume request for blocked records. Supplied only for database, diskette, and tape files.
128	Binary	2	For output, 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. For input, the field value is the record format length, including response indicators and source sequence numbers. If the value is zero, use the field at offset 42.
130	Character	2	Reserved.
132	Binary	4	Current block count. The number of blocks of the tape data file already written or read. For tape files only.
136	Character	8	Reserved.

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Parent topic:

I/O feedback area