== Retuil DASD Star! of LOGREC Execution of DIAGNOSE code X'2C' allows a user with privilege class C,
E, or F to find the location on the disk of the error recording area,
the number of error recording cylinders, and the location of the first
error record.
The register specified as Rx contains a one-byte code in the
low-order byte, indicating the function to be performed: X'01' - Return the DASD location of the start of the error recording
area, and the number of error recording cylinders. X'02' - Return the HDRSTART value (DASD location of first error
record). X'04' - Return indication of whether there are frame records on the
error recording cylinders. On return to the issuer of DIAGNOSE '2C':
If code '01' is specified: Register Rx will contain the DASD location (in V8/370 control program internal format) of the start of
the error recording area. Ry contains, in the low-order halfword,
the number of error recording cylinders.
If code '02' is specified: Register Rx will contain the DASD location of the first error record (in CCPD format). The value
actually points to the last frame record written, or record 2 if no
frame records present.
If code '04' is specified: Register Ry will contain a X'02' in the
low-order byte if frame records are present on the error recording
cylinders; 1'00' if no frame records present.
Bote: Codes '02' and '04' may both be specified (code '06') on invoking DIAGNOSE. Both an Rx and Ry value must be specified • Code == Read Pag!! of LOGREC Execution of DIAGNOSE code X'30' allows a user with privilege class C,
E, or F to read one page of the system error recording area. The
register specified as Rx contains the DASD location (in V8/370 control program internal format) of the desired record. The Ry register
contains the virtual address of a page-size buffer to receive the data.
The D8KRPAGT routine supplies the page of data. The condition codes
returned are:
Condition
Code
---0----
1
2
3 Successful read, data available
End of cylinder, no data
I/O error
Invalid cylinder, outside recording area Code == SIs!U Duap ..§Rool File
A user with privilege class C or E can read the system spool file by issuing a DIAGBOSE code X'34' instruction. The register specified as Rx contains the virtual address of a page-size buffer to receive the data.
The Ry register, which must not be register 15, contains the virtual
1-62 IBM Y8/370 System Logic and Problem Deteraination--Volume 1

address of the spool input card reader. Ry+1, on return, may contain
error codes as follows:
condition Ry+1
Error_Code Code
o
1
2
3
3
3
3 4 8
12
16 Data transfer successful
End of file
File not found
Device address invalid
Device type invalid
Device busy
Fatal paging I/O error
The D8KDRDMP routine searches the system chain of spool input files
for the duap file belonging to the user issuing the DIAGNOSE instruction. The first (or next) record from the dump file is provided to the virtual :achine via D!KRPIGT and the condition code is set to zero. The dump file is closed via V8/370 console function CLOSE. Execution of DIAGNOSE code X'38' causes the routine D!KDBDSY to read the
system table into storage.. The register specified as Bx contains the
address of the page buffer to contain the syabol table. DIAGNOSl! = VML370 J2irectory Execution of DIAGNOSE code X'3C' allows a user to dynamically update the Y8/370 directory. The register specified as Rx contains the first 4 bytes of the volume identification. The first two bytes of By contain
the last 2 bytes of the voluae identification. The routine D!KUDRDS dynamically updates the directory. :::: Accoun!ing Cards for the Virtual Use! This code can be issued only by a user with the account option (ACCT) in
his directory. Rx contains the virtual address of either a 24-byte paraaeter list
identifying the "charge to" user, or a variable length data area that is
to be punched into the accounting card. The interpretation of the
address is based on a hexadeciaal code supplied in RY. If the virtual
address represents a paraaeter list, it must be doubleword aligned; if
it represents a data area, the area must not cross a page boundary. If Rx is interpreted as pointing to a parameter list and the value in Rx is
zeros, the accounting card is punched with the identification of the
user issuing the DIAGNOSE instruction. Ry contains a hexadeciaal code interpreted by D!KHVC as follows:
Code '0'0'00 0004 0008 OOOC 0010 !.! E2int§ !Q: a paraaeter list containing only a userid.
a paraaeter list containing a userid and account number. a paraaeter list containing a userid and distribution
nu.ber.
a paraaeter list containing a userid, account nu.ber, and
distribution nu.ber.
a data area containing up to 70 bytes of user information to
be transferred to the accounting card starting in colu.n
9.
CP Introduction 1-63