Page of GC20-1S07-7 As Updated April 1, 19S1 by TNL GN25-0S29 SU BCODE X' OFFF' Rx virtual address of a 252-byte buffer
Ry spool file ID number
If Ry is nonzero, the spool input chain is searched for a file with a matchinq ID number: nOne is found or if one is found that is owned
by a different virtual machine, cc=2 is set. The chain search is
continued from the file that was found, or from the anchor if Ry is
zero, for the next file owned by the caller, independent of file type,
class, INUSE flag, etc. If none is found, cc=1 is set. Otherwise, the SFBLOK and the first record of the file (generally, the TAG) are copied
to the caller's virtual storage buffer. DIAGNOSE Code X'18' --Standard DASD I/O Input/output operations to a direct access device, of the type used by CMS, can be performed from a virtual machine using DIAGNOSE Code X'lS'. No I/O interrupts are returned by CP to the virtual machine; the DIAGNOSE instruction is completed only when the READ or WRITE commands
associated with the DIAGNOSE are completed. The Rx register contains
the virtual device address of the direct access device. The Ry register
contains the address of a chain of CCWs. The CCW chain must be in a
standard format that CP expects when DIAGNOSE Code X'1S' is used, as
shown below. DIAGNOSE must not be used to read or write
record-overflow-formatted data. Register 15 must be loaded by the user
with the number of READS or WRITEs in the CCW chain.
A typical CCW string to read or write two SOO-byte records is as
follows:
SEEK,A,CC,6 SET SECTOR (not used for 2314/2319)
SRCH,A+2,CC,5 TIC,*-S,O,O RD or WRT,DATA,CC+SILI,SOO SEEK HEAD,B,CC,6 (omitted if HEAD number unchanged) SET SECTOR SRCH,B+2,CC,5 TIC,*-S,O,O RD or WRT,DATA+SOO,SILI,SOO A SEEK and SRCH arguments for first RD/WRT B SEEK and SRCH arguments for second RD/WRT The condition codes and completion codes returned are as follows: cc=O I/O complete with no errors
cc=1 Error condition. Register 15 contains one of the following:
R15=1
R1S=2
R15=3
R15=4
R15=5
Device not attached
Device not 2319, 2314, 3330, 3340, or 3350 Attempt to write on a read-only disk
Cylinder number not in range of user's disk
virtual device is busy or has an interrupt pending 190 IBM VM/370 System programmer's Guide

cc=2 Error condition. Register 15 contains one of the following: ..... r_r .t\IJ-J R15=6
R15=7
R15=8
R15=9 R15=10 R15=11
R15=12 __ L_ __ __ __ __ ... SEEK/SEARCH arguments not within range of user's
storage READ/WRITE CCW is neither Read (06) nor Write (05) READ/WRITE byte count=O READ/WRITE byte count greater than 2048 READ/WRITE buffer not within user's storage
The value in R15, at entry, was not a positive number
from 1 through 15, or was not large enough for the
given CCW string.
Cylinder number on seek head was not the same number as
on the first seek.
cc=3 Uncorrectable I/O error:
R15=13 CSW (8 bytes) returned to user
Sense bytes are available if user issues a SENSE command DIAGNOSE Code X'1 C' -- Clear Error Recording
Cylinders
Execution of DIAGNOSE Code X'1C' allows a user with privilege class F to
clear the error recording data on disk. The DMKIOEFM routine performs
the clear operation. The register specified as Rx contains a one-byte
code value in the low-order byte as follows: Function X'01' Clear-and reformat all error recording, leaving any
frame records intact X'02' Clear and reformat all error recording cylinders. erasing
both frame records and error records DIAGNOSE Code X'20' -- General I/O With DIAGNOSE ccw chain to DIAGNOSE must
data on DISD .achine; the
commands in
specified as
contains the
Code X'20', a virtual machine user can specify any valid
be performed on a tape or disk device. (An exception:
not be used to read or write record-overflow-formatted devices.) No I/O interrupts are reflected to the virtual DIAGNOSE instruction is completed only when all I/O the specified CCW chain are finished. The register
Rx contains the virtual device address. The Ry register
address of the CCW chain.
The celis are processed via DMKCCWTR through DMKGIOEX. providing full
virtual I/O in a synchronous fashion (self-modifying CClis are not permitted, however) to any virtual machine specified. Control returns
to the virtual machine only after completion of the operation or
detection of a fatal error condition. EREP support is provided for tape
and DASD devices only; all other devices will present an error conditien
in the PSi to the virtual user. Condition codes and error codes are
returned to the virtual system.
The condition codes and error codes returned are as follows: cc=O I/O completed with no errors Part 2. Centrol Prograa (CP) 191