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1<br />
Offset<br />
o<br />
1<br />
8<br />
13<br />
20<br />
25<br />
36<br />
(0) 1<br />
Bytes and<br />
Alignment<br />
(1) • 1<br />
(8) 5<br />
(D) • 1<br />
(14) 5<br />
(19) • 11<br />
(24) 8<br />
44 (2C) 1<br />
45 (20) • 1<br />
46 (2E) •• 1.<br />
41 (29) • 3<br />
50 (32) •• 2<br />
52 (34) 1<br />
53 (35) • 1<br />
I 54 (36) •• 1<br />
55 (7) ••• 1<br />
56 (38) 1<br />
51 (39) • 1<br />
58 (3A) •• 1<br />
59 (3B) ••• 2<br />
61 (3D) • 3<br />
FORMAT 2 -- INDEX DATA SET CONTROL BLOCK<br />
Field Hex.<br />
Name Dig. Field Description, Contents, Meaning<br />
!)S22MINO<br />
DS2L2MEN<br />
DS23MIND<br />
DS2L3MIN<br />
DS2LPDT<br />
DS2FMI'ID<br />
DS2NOLEV<br />
DS20VIND<br />
DS21RCYL<br />
DS2LTCYL<br />
DS2CYLOV<br />
DS2HIRIN<br />
DS2HIRPR<br />
DS2HIROV<br />
DS2RSHTR<br />
DS2HIRTI<br />
DS2HIIOV<br />
OS 2 TAGDT<br />
DS2RORG3<br />
02<br />
Hex code 02 - provides a unique key field.<br />
Address of the first track of the second level master<br />
index in the form MBBCCHH.<br />
CCHHR of the last active index entry in the second<br />
level master index.<br />
Address of the first track of the third level master<br />
index in the form MBBCCHH.<br />
CCHHR of the last active index entry in the third<br />
level master index.<br />
Reserved.<br />
118 OS <strong>System</strong> control <strong>Blocks</strong> (Release 21.7)<br />
Last prime track on the last prime cylinder.<br />
Format identification for format 2 OSCB. (EBCDIC<br />
-2-.)<br />
Number of index levels. A binary number indicating<br />
how many levels of index are present with an indexed<br />
sequential data set.<br />
Number of tracks determining development of the<br />
master index.<br />
HHR of the first data record on each cylinder.<br />
HH of the last data track on each cylinder.<br />
Number of tracks of cylinder overflow area on each<br />
cylinder.<br />
Highest possible R on a track containing high level<br />
index entries.<br />
Highest possible R on prime data tracks for format F<br />
records.<br />
Highest possible R on overflow data tracks for format<br />
F records.<br />
R of the last data record on a shared track.<br />
Highest possible R on an unshared track of the track<br />
index.<br />
Fixed-length record format:<br />
Highest possible R for independent overflow data<br />
tracks. Variatle-length record format: Unused.<br />
User supplied number of records tagged for deletion.<br />
This field is merged to and from the DCB for BISAM,<br />
QISAM scan mode, and resume load.<br />
A count of the number of READ and WRITE accesses,<br />
made during the last use of the data set, to an<br />
overflow record that is not first in a chain of such<br />
records.
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