IBM System/370 145 Manual page 230

Subject to the restrictions stated in Section 10:05 and at the end of
this subsection, alteration of an existing source program is required
only if new processing is added, if existing processing is changed, if
there is a change in the I/O device types used in the program (ASSGN job
control statements may also require changes), or if the program contains
a user-written routine that depends upon a particular release of DOS for
communication with the supervisor. (Conversion of emulated programs and
files is discussed in Section 40.)
Existing printer programs that specify the 1403 Printer in the OTF
(either by default or specifically) can be used without change for a
3211 Printer to support the same functions as before. Additional job
steps that load the FCB and the UCB must be added to the input stream
where appropriate. Source programs must be modified if support of any
of the new ~211 features (retry after error, etc.) is desired or if a
function or feature that was not used previously is to
be
supported on
the 3211.
Conversion from 2311s (or 2321s) to a 2319 or 2314 facility involves
transfer of the data to the new devices, and program and job control
statement modifications. (The same procedures are required for
conversion from 2314s to 3330-series drives.:) The amount of program
alteration required depends on the file organization used and changes
made to take advantage of the larger capacity of the new disk pack
(larger blocking factors, changes in ISAM area allocations, etc). In
all cases, the DTF in the program must be modified to specify the new
direct access device, and if block size is changed, I/O'areas must be
redefined. Device assignments and extents specified in the job control
statements for these programs must be changed also. VOL, DLAB, and
XTENT control statements are not supported for 3330-series files. DLBL
and EXTENT statements must be used.
sequentially organized files on 2311s or 2321s (processed by S~) can
be copied directly from the source direct accesss device to the new
device, using the Disk-to-Disk or Data Cell-to-Disk utility.
Alternatively, files can be dumped to tape and then loaded on the new
disk pack, using disk-to-tape and tape-to~disk utilities if the source
direct access device is not in the Model 145 configuration.
Indexed sequential and directly organized files (processed using ISAM
and DAM, respectively) must be transferred to the new disk pack with a
user-written program. The original creation or reorganization program
with appropriate_ modifications can probably be used. The randomizing
routine used in programs that process directly organized files must be
modified if relative track or actual track address record reference is
used and fewer or more tracks are allocated 'to the file than before.
User-written programs that use the EXCP macro to access files that
have been transferred to new disk packs may have to be modified to
reflect the characteristics of the file on the new pack, a different
number of records per track, a different number of tracks per cylinder,
etc. All 2311 CCW lists will operate on 2314/2319 disk drives except
those that are device or channel time dependent. CCW lists for the 2321
will operate also, except when they contain a device-dependent command
such as RESTORE.. (All 2314 CCW lists will operate on 3330"';series drives
except those that are device or channel time dependent and those that
support the file scan feature, which is not available on the 3330-
series.)
The OS discussion of conversion of existing tape programs and their
existing tape volumes for use with a 3410/3411 or 3803/3420 tape
subsystem applies to DOS also, except that a change in a parameter, such
as blocking factor, involves alteration of the program (tape DTF). In
addition, recording mode changes involve job control (ASSGN) statement
alteration only (not DTF modification).
220 A Guide to the IBM System/370 Model 145