IBM 5280 Maintenance Information Manual page 84

Exchange Type Indicator (byte 43): Indicates that the
data set has specified attributes. This field is used as a
summary indicator for certain other fields in this label
as follows:
space Basic exchange data set for 31 SD
H Basic exchange data set for 51 TD
E No summation of the attributes exists
The space and H indicate the following attributes:
• Physical record size is 128 bytes for 31 SD, 256 bytes
for 51TD
• Unblocked, unspanned records
• Record length maximum is 128 bytes for 31 SD, 256
bytes for 51 TD
• Sequentially organized
• Data set identifier is a single name of up to eight
characters
• Data in the data set must be recorded in EBCD IC,
ASCII, or user code and must be in the same code as
the data set label describing it.
• The data set label must reside on cylinder O.
Multivolume Indicator (byte 44): Indicates if the data
set is complete on this diskette or is continued on another
diskette. This field will contain one of the following:
C Data set continued on another diskette
L
space
This is the last volume of a multivolume
data set
The complete data set is contained on this
diskette
Volume Sequence Number (bytes 45 through 46):
Indicates the volume number of this diskette in a
multivolume data set.
Cr,eation Date (bytes 47 through 52): Indicates the date
this data set was created. This field is coded YYMMDD
or all space characters.
72 Theory
Record Length (bytes 53 through 56): Indicates the
length of a stored logical record to be transferred to an
application program. This field will contain the numeric
value of the length of the logical record or will contain
spaces. A space in this field means that the record length
equals the block length.
Offset to Next Record Space (bytes 57 through 61):
Indicates the starting position of the next sequential record
relative to the end of the last block preceding the EOD
(end of data) address. This field will contain either spaces
or a decimal value to be used as a negative displacement
value.
Reserved (bytes 62 through 65):
Expiration Date (bytes 66 through 71): Indicates the date
on which this data set can be destroyed. This field is
coded YYMMDD for data sets that can be destroyed or
999999 for data sets which cannot be destroyed.
Verify/Copy Indicator (byte
72): Indicates if the data
set has been verified. In verify mode, this field will contain
a V when the last nondeleted record in the data set has
been processed.
Data Set Organization (byte 73): Indicates how the data
set is organized. If SEQ (sequential) is specified, the field
is set to D. If SEQ is not specified, the field is set to space.
End of Data Address (bytes 74 through 78): Indicates the
address of the next available unused block in the extent.
The first two bytes are the cylinder number, the next byte
is the head number, and the last two bytes are the sector
number.