PROGRAM STATUS WORD System Mask" 33 Interruption Code
23 24 I nstruction Address
47 48 SS S6
13 Machine check mask (M)
14 Wait state (W)
15 Problem state (P)
31
63
o Channel 0 mask
1 Channell mask
2 Channel 2 mask
3 Channel 3 mask
4 Channel 4 mask
5 Channel 5 mask
32-33 Instruction length code OLC) 34-35 Condition code (CC)
6 Mask for channel 6 and up
7 External mask
12 ASCII-S mode (A)
36 F ixed-point overflow mask
37 Decimal overflow mask
38 Exponent underflow mask
39 Significance mask
*A one-bit equals on, and permits an interrupt.
CHANNEL ADDRESS WORD I Key I 0000 I Command Address
o 3 4 7 8
CHANNEL COMMAND WORD Data Address I Command Code I o 7 8 IS116 23 1 24
Byte Count SSIS6 CD-bit 32 (SO) causes use of address portion of next CCW.
CC-bit 33 (40) causes use of command code and data address of next CCW.
SLI-bit 34 (20) causes suppression of possible incorrect length indication.
Skip-bit 35 (10) suppresses transfer of information to main storage. PCI-bit 36 (OS) causes a channel Program Controlled Interruption. CHANNEL STATUS WORD I Key I 0000 I Command Address
0 3 4 7 8 IS116 23
1
24 I Status 4)48 Byte Count
32 39
1
40 SS IS6 31
31
63
31
63 I I 32 (8000) Attention 40 (OOSO) Program-controlled interruption
33 (4000) Status modifier 41 (0040) Incorrect length
34 (2000) Control unit end 42 (0020) Program check
35 (1000) Busy 43 (0010) Protection check
36 (0800) Channel end 44 (OOOS) Channel data check
37 (0400) Device end 45 (0004) Channel control check
38 (0200) Unit check 46 (0002) Interface control check
39 (0100) Unit exception 47 (0001) Chaining check
Byte Count: bits 48-63 form the residual count for the I·ast CCW used.
Comments about this card may be sent to the Technical Pub­
lications Department at the White Plains address below. All comments and suggestions become the property of IBM. International Business Machines Corporation
Data Processing Division
1133 Westchester Ave., White Plains, N.Y. 10604 (U.S.A. only) I BM World Trade Corporation
821 United Nations Plaza, New York, New York 10017 (International) Printed in U.S.A. GX2()'1703-9

PERMANENT STORAGE ASSIGNMENTS Dec Hex Length Purpose 0 0 double word I nitial program loading PSW 8 8 double word Initial program loading CCW1
16 10 double word Initial program loading CCW2
24 18 double word External old PSW 32 20 double word Supervisor Call old PSW 40 28 double word Program old PSW 48 30 double word Machine-check old PSW 56 38 double word Input/output old PSW
64 40 double word Channel status word
72 48 word Channel address word
76 4C word Unused 80 50 word Timer (uses bytes 50, 51 & 52)
84 54 word Unused
88 58 double word External new PSW
96 60 double word Supervisor Call new PSW 104 68 double word Program new PSW
112 70 double word Machine-check new PSW 120 78 double word Input/output new PSW 128 80 ( 1) Diagnostic scan-out area
(1) The size of the diagnostic scan-out area depends on the particular model and I/O channels, for models 30 through 75, maximum size is 256 bytes.
CHANNE L COMMANDS 2314,2311/2321DASD Source: GA26-3599, GA26·5988 Command for CCW:j: Count MT Off MTOnt Control Seek 6 07 Seek Cylinder 6 OS Seek Head 6 18
Set File Mask 1 1F Space Count 3 OF Recalibrate (Note 1) Not zero 13
Restore (2321 only) Not zero 17 Sense Sense I/O 6 04 Release Devi.ce }(Note 2) 6 94
Reserve DeVice 6 84 Search Home Address EO 4 (usually) 39 89 Identifier EO 5 (usually) 31 81 Identifier HI 5 (usually) 51 01 Identifier EO or HI 5 (usually) 71 F1
Key EO 1 to 255 29 A9
Key HI 1 to 255 49 C9
Key EO or HI 1 to 255 69 E9
Key & Data EO 2D AD
Key & Data HI Number 4D CD
Key & Data EO or HI of bytes 6D ED
Continue Search EO in search
25 A5 Scan Search HI argument,
45 C5 Search HI or EO including
65 E5 Set Status Modifier*
mask bytes.
35 85
Set Status Modifier* (Special 75 F5
No Status Modifier
feature.)
55 05 Read Home Address 5 1A 9A
Count 8 12 92
Record 0 16 96
Data
}
Number 06 86
Key & Data of bytes OE 8E
Count, Key & Data transferred 1E 9E IPL 02 Writ., Home Address 5 (usually) 19
Record 0 8+KL+DL of RO 15
Count, Key & Data 8+KL+DL 10 Special Count, Key & Data 8+KL+DL 01 Data DL 05 Key & Data KL+DL OD
Erase 8+KL+DL 11
1. For 2311 or 2314 only. *Sense byte determines command used.
2. Two-c:hannel switch requ ired except tCode same as MT Off except as listed. for a 2314/2844 combination. :j:See also standard commands, panel 10.