You then issue the FILEDEF command to assign a CMS file identification
to the OS data set or DOS file so that CMS can read it. The format of
the FILEDEF command used for this purpose is: r r .,., r ., FIledef IDISK fn ft Ifmll IDSN ? I I l!lll IDSN q1 [q2 ••• ]1
L L ... .J L .J r r DISK Ifn ft Ifm'l IA11 I L L .J.J DUMMY r ., me.bernamel !CONCAT L .J
If you are issuing a FILEDEF for a DOS file, note that the OS prograa
that viII use the DOS file must have a DCB for it. For "ddna.e" in the
FILEDEF com.and line, use the ddname in that DCB. With the DSN operand,
enter the file-id of the DOS file. Soaetiaes, CMS issues the FILEDEF command for you. Although the CMS KOYEFILE co.aand, the supported CMS program product interfaces, and the CMS OPEN routine each issue a default FILEDEF, you should issue the
FILBDEF co •• and yourself to ensure the appropriate file is defined.
After you have issued the ACCESS and FILEDEF commands for an OS sequential or partitioned data set or DOS sequential file, commands (such as ASSEMBLE and STATE) can refer to the OS data set or DOS file
just as if it vere a CMS file. Several other CMS commands can be used vith as data sets and DOS files that do not reside on CMS disks. See the for a complete description of the CMS ACCESS, FILEDEF, LISTDS, MOYEFILE, QUERY, RELEASE, and STATE co.mands. For restrictions on reading OS data sets and DOS files under CMS, see
the The CMS FILEDEF comaand allows you to specify the I/O device and the
file characteristics to be used by a program at execution time. In
conjunction with the as simulation scheme, FILEDEF simulates the
functions of the data definition JCL statement.
FILEDEF aay be used only with programs using OS macros and functions.
For example:
filedef file1 disk proga data a1
After issuing this com.and, your program referring to FILE1 would access PROGA DATA on your A-disk.
2-46 IBM VM/370 System Logic and Program Determination--Volume 2
If you wished to supply data from your terminal for FILE1, you could
issue the command:
filedef file1 terminal
and enter the data for your program without recompiling.
fi tapein tap2 (recfm fb lrecl 50 block iOO 9track den 800) After issuing this co •• and, programs referring to TAPEIN will access a
tape at virtual address 182. (Each tape unit in the CMS environment has
a symbolic name associated with it.) The tape must have been previously
attached to the virtual machine by the Vft/370 operator.
The AUIPROC option can only be used by a program call to FILEDEF and not
from the terminal. The CMS language interface programs use this feature
for special I/O handling of certain (utility) data sets.
The AUIPRoe option, followed by a fullword address of an auxiliary
processing routine, allows that routine to receive control from DMSSEB before any device I/O is performed. At the completion of its processing,
the auxiliary routine returns control to DMSSEB signaling whether or not I/O has been perfor.ed. If it has not been done, DMSSEB performs the
appropriate device I/O. When control is received from DMSSEB, the general-purpose registers
contain the following information: GPR2 = Data Control Block (DCB) address
GPR3 = Base register for DMSSEB GPR8 = CftS OPSECT address
GPR11 = File Control Block (FCB) address GPR14 Return address in DMSSEB GPR15 = Auxiliary processing routine address
all other registers = Work registers
The auxiliary processing routine must provide a save area in Wh1Ch to
save the general registers; this routine must also perfor. the save
operation. DMSSEB does not provide the address of a save area in
general register 13, as is usually the case. When control returns to the general registers must be restored to their original values.
Control is returned to by branching to the address contained in
general register 14.
GPR15 is used by the auxiliary processing routine to inform to DMSSEB of the action that has been or should be taken with the data block as
follows: Action GPR15=O No I/O performed by !UIPROC routine; DMSSEB will perform I/O. GPR15<O GPR15>O I/O performed by !DIPROC routine and error was encountered. DMSSEB will take error action. I/O performed by AUXPROC routine with residual count in GPR15; DMSSEB returns nor.ally.
GPR15=64K I/O perfor.ed by lUIPROC routine with zero residual count. CMS Introduction 2-47
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