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Hex Dec Type/Val Lng Label (dup) Comments
---- ---- --------- ---- -------------- --------
0000 0 Structure LEDA Locate Record Extended data area
0000 0 Bitstring 16 LEDAREA (0) Locate Record Extended data area
Byte 0 (Operation byte)
Although defined as BITs, the contents of the
operation byte are, architecturally, multiple
codes.
0000 0 Bitstring 1 LEDOP Operation byte
11.. .... LEDOR X'C0' LEDOR Operation byte, bits
0 and 1 ------- Codes for use
with LEDOR
.... .... LEDORCA X'00' LEDORCA Orient on count
area
.1.. .... LEDORHA X'40' LEDORHA Orient on home
address
1... .... LEDORDA X'80' LEDORDA Orient on data area
11.. .... LEDORIX X'C0' LEDORIX Orient on index
-------
..11 1111 LEDOOC X'3F' Operation byte, bits 2
through 7 ------- Codes for use
with LEDOOC
.... ...1 LEDOCWD X'01' Write data
.... ..11 LEDOCFW X'03' Format write
.... .11. LEDOCRD X'06' Read data
.... 1.11 LEDOCWT X'0B' Write track
.... 11.. LEDOCRT X'0C' Read tracks
...1 .11. LEDOCR X'16' Read
..11 1111 LEDOCX X'3F' Extended Op Code -------
Byte 1 (Auxiliary byte)
0001 1 Bitstring 1 LEDAUX Auxiliary byte
1... .... LEDAVTLF X'80' LEDAVTLF Validate transfer
length factor
.... ...1 LEDARCS X'01' LEDARCS Read count suffix
Byte 2 (Zeros)
0002 2 Bitstring 1 LEDZEROS Must be zeros
Byte 3 (Count)
0003 3 Bitstring 1 LEDCOUNT Count
Bytes 4 through 7 (Seek address)
0004 4 Bitstring 4 LEDSEEK (0) Seek address (CCHH)
0004 4 Bitstring 2 LEDSCC CC of CCHH
0006 6 Bitstring 2 LEDSHH HH of CCHH
Bytes 8 through 12 (Search argument)
0008 8 Bitstring 5 LEDSRCH (0) Search argument (CCHHR)
0008 8 Bitstring 2 LEDRCC CC of CCHHR
000A 10 Bitstring 2 LEDRHH HH of CCHHR
000C 12 Bitstring 1 LEDRR R of CCHHR
Byte 13 (Sector number)
000D 13 Bitstring 1 LEDSECT Sector number
1111 1111 LEDNOSCT X'FF' LEDNOSCT Sector orientation
not performed
Bytes 14 and 15 (Transfer length factor)
000E 14 Bitstring 2 LEDTLF Transfer length factor
Byte 16 (Reserved)
0010 16 Bitstring 1 LEDRES Reserved for IBM use
Byte 17 (Extended Operation)
0011 17 Bitstring 1 LEDEOP Extended Operation
.... .... LEDOTHOP X'00' LEDOTHOP Use operation code
in byte 0
.... 1..1 LEDWRANY X'09' LEDWRANY Write Any
.... 1.1. LEDRDANY X'0A' LEDRDANY Read Any
.... 111. LEDRDTKS X'0E' LEDRDTKS Read Trackset
...1 .... LEDPRETS X'10' LEDPRETS Prestage Trackset
...1 ...1 LEDWRTKS X'11' LEDWRTKS Write Trackset
...1 ..11 LEDUWRTK X'13' LEDUWRTK Update Write
Trackset
Bytes 18-19 (Extended Parameter Length)
0012 18 Bitstring 2 LEDEPLEN Extended Parameter Length
Bytes 20-21 (Extended Parameter)
0014 20 Bitstring 1 LEDEPRM1 Extended Parameter byte 1
0015 21 Bitstring 1 LEDEPRM2 Extended Parameter byte 2
Length equates
00000016 LEDBSIZE *-LEDAREA Size of LEDA in bytes
00000003 LEDSIZE ((*-LEDAREA)+7)/8 Size of LEDA in
DWs
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