Advertisement
INPUT/OUTPUT
FUNCTIONS
25.3 -- Device Independent I/O Functions
IOCB FLAG DESCRIPTION SUMMARY
Field
Name Bit
IOCDTT
10
6-7
IOCLUN
S
5
a
4
T
3
F
2
M
0-1
7
R
6
LUN 0-5
IOCFDF
W
F
D
E
S
o
c
C
N
B
Content
I/O transfer flag
Bit 6:
1
=)
Output transfer
Bi t
7:
1
=>
Input transfer
Sector/record flag
o
=)
Record I/O
1
=)
Sector
IiO
Open/closed flag
o
=)0
File open
1 =::> File closed
Truncate flag
o
=>
Ignore truncate action
1
=)
Truncate file upon closing
Non-file format flag
o
=)0
File format mode
1
=)
Non-file format mode
Mode flag
00
=:>
Update mode,
existing file
01
=::>
Input mode,
existing file
10
=)
Output mode,
new
file
11
=)
Update mode,
any file
Not used
<=0)
Reserved flag
o
=)
lOeB
released
1
=::> lOeB
reserved
Logical unit number ($30-$39)
Write protection bit
o
=)
No write protection
1
=)
Write protected
Delete protection bit
o
=::>
No delete protection
1
=)
Delete protected
System file bit
o
=)
Non-system file
1
=)
System file
Contiguous allocation bit
o
=)
Segmented allocation
1
=)
Contiguous allocation
Non-compressed space bit
o
=)
Spaces compressed
1
=)
Spaces non-compressed
Page
25-17
Advertisement
