Recording of descriptor fields
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6.10.3 Fixed-length
records
A fixed-length record shall be a record contained in a file that is assigned to contain records that must have the
same length.
A fixed-length record shall be contained in an MDU. The MDU shall consist of the fixed-length record,
immediately followed by a (00) byte if necessary to give the MDU an even length.
The minimum assigned length of a fixed-length record shall be 1.
6.10.4 Variable-length
records
A variable-length record shall be a record contained in a file that is assigned to contain records that may have
different lengths. The value recorded in the Record Format field of an Extended Attribute Record for a file
containing variable-length records shall contain the same value as that recorded in the Record Format field of
any other Extended Attribute Record of that same file.
A variable-length record shall be contained in an MDU. The MDU shall consist of a Record Control Word
(RCW) immediately followed by the variable-length record, immediately followed by a (00) byte if necessary to
give the MDU an even length.
The RCW shall specify as a 16-bit number the length of the record. The RCW shall be recorded according to
- 7.2.1, if the value in the Record Format field of the Extended Attribute Record associated with the File
Section is 2, or
- 7.2.2, if the value in the Record Format field of the Extended Attribute Record associated with the File
Section is 3.
A maximum record length shall be assigned for a file. The length of any record in the file shall not exceed this
value. The assigned maximum record length shall be in the range 1 to 32,767. The minimum length of a
variable-length record shall be 0.
7
Recording of descriptor fields
7.1
8-bit numerical values
A numerical value represented in binary notation by an 8-bit number shall be recorded in a field of a descriptor in
one of the following two formats. The applicable format is specified in the description of the descriptor fields.
7.1.1
8-bit unsigned numerical vaiues
An unsigned numerical value shall be represented in binary notation by an 8-bit number recorded in a one-byte
field.
7.1.2
8-bit signed numerical values
A signed numerical value shall be represented in binary notation by an 8-bit two's complement number recorded
in a one-byte field.
7.2
16-bit numerical value
A numerical value represented in binary notation by a 16-bit number shall be recorded in a field of a descriptor in
one of the following three formats. The applicable format is specified in the description of the descriptor fields.
7.2.1
Least significant byte first
A numerical value represented by the hexadecimal representation (wx yz) shall be recorded in a two-byte field
as (yz wx).
NOTE 9
For example, the decimal number 4660 has (12 34) as its hexadecimal representation and is recorded as (34
12).
7.2.2
Most significant byte first
A numerical value represented by the hexadecimal representation (wx yz) shall be recorded in a two-byte field
as (wx yz).
NOTE 10
